[core] Fail dev HMR cleanup on a stranded step registration - #3682

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Aug 25, 2026
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[core] Fail dev HMR cleanup on a stranded step registration#3682
VaguelySerious merged 3 commits into
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peter/windows-step-registration-cleanup

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@VaguelySeriousVaguelySerious commented Aug 19, 2026

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Problem

Three of the last 120 Tests runs had E2E Windows Tests (node) burn its full ~30-minute
window and get cancelled with every e2e test failing on
[world-local] Queue message failed (HTTP 500), where the handlerError is a Next.js
_error page rather than anything workflow-shaped:

jobflow-route 500sstranded-import errors
9622825337310,13520,346
9621451553010,21810,886
9620285500910,28020,557

The flow route never answered a single request successfully in any of them. The dev server
log says why:

⨯ app/.well-known/workflow/v1/flow/__step_registrations.js:33:1
Module not found: Can't resolve '../../../../../workflows/source-map-warning-fixture.ts'

dev.test.ts > "should not log source map warnings for workflow node_modules imports"
writes workflows/source-map-warning-fixture.ts, which declares a 'use step' function,
and its afterEach deletes it. The generated __step_registrations.js imports every
discovered step file by path, so that deletion only stops breaking the flow route once a
rediscovery regenerates the file. When the watcher drops the unlink — which is what happens
on Windows — the generated file keeps importing a path that no longer exists, the flow route
stops compiling, and every workflow dispatch for the rest of the job gets a 500 pointing at
a fixture from a test that already passed.

The HMR log confirms nothing recovers it: 164 → 165 → 166 → 165 → 165 workflows, then
three skips and no further rediscovery. afterEach's prewarm() only waits for
workflow dev hmr: ready, printed once at startup, so nothing ever waited for the
post-deletion rediscovery in the first place.

The generated workflow bundle inlines workflow sources instead of importing them, so only
step-declaring fixtures can strand it. That is why new-workflow.ts leaks harmlessly in
the same runs while the source-map fixture is fatal.

The existing fail-fast guard cannot see this

The Windows job already probes the dev server before the long e2e run, precisely to avoid
burning the job window on a wedged server. It probes GET /api/chat, which compiles
independently of the flow route, so it reported -> 405 and let the suite run in all three
jobs.

Changes

  1. packages/core/e2e/dev.test.ts — after deleting fixtures, cleanup waits for the
    generated step registrations to stop importing them. If they still do when the budget
    runs out, the fixture contents are written back so the shared dev server keeps serving
    the rest of the suite, and the hook fails naming the stranded file. CI already skips the
    e2e suite when dev.test.ts fails, so this turns a 30-minute burn with ~10k misleading
    500s into an immediate, accurate failure. The convergence wait runs before the
    node_modules fixture-package removal so a restored fixture still resolves its import.

  2. .github/workflows/tests.yml — the pre-e2e probe now POSTs
    /.well-known/workflow/v1/flow?__health, the SDK's own health endpoint on the route
    that actually breaks. It returns 200 on a healthy dev server and would have returned 500
    in all three jobs above.

Validation

Run locally against workbench/nextjs-turbopack on macOS (all 9 dev tests, so including
the flow-route HMR fuzz cases that also delete step-declaring files):

  • Happy path: the convergence wait never trips on any of the tests that delete fixtures. A
    deletion converges in ~2s, so the watcher path itself is sound and the Windows miss is the
    discriminator.
  • should follow Next flow-route HMR rebuild rules for body-only changes fails on macOS
    (expected 2 to be 1 on an exact HMR log count). It fails identically with unmodified
    origin/main's dev.test.ts against the same dev server, so it is pre-existing and
    unrelated. That case is skipped on Windows.
  • Forced-failure path (convergence budget shortened so it always expires): the hook fails
    with the stranded path named, the fixture is restored, and
    POST /.well-known/workflow/v1/flow?__health still answers 200.
  • POST /.well-known/workflow/v1/flow?__health returns 200 on a healthy dev server and 500
    when a path reachable from __step_registrations.js does not resolve, while
    GET /api/chat keeps answering 405 — the asymmetry the second change fixes.

The underlying Windows watcher miss is worth chasing separately; this PR stops it from
costing a whole job and makes it name itself.

Note on a related hole, not changed here

The Linux e2e-local-dev lane runs pnpm vitest run packages/core/e2e/dev.test.ts; sleep 10
and then continues into the full e2e suite, so a dev.test.ts failure there is discarded.
That lane would swallow the new hook failure too. Tightening it would newly red the lane on
pre-existing dev.test.ts flakes (the flow-route HMR fuzz case already fails on macOS
against unmodified main, see below), so it seemed worth raising separately rather than
bundling in.

@VaguelySerious@claude
[core] Fail dev HMR cleanup on a stranded step registration
62fcd0f
`dev.test.ts` fixtures that declare a `'use step'` function are imported by
path from the generated `__step_registrations.js`, so deleting one only stops
breaking the flow route once a rediscovery regenerates that file. When the dev
server's watcher drops the unlink, the generated file keeps importing a path
that no longer exists: the flow route stops compiling and every later workflow
dispatch in the job gets a 500 that names a fixture from a test that already
passed. Three of the last 120 `Tests` runs lost the whole ~30-minute Windows
e2e window this way, each with ~10k flow-route 500s and no successful dispatch.
Cleanup now waits for the generated step registrations to drop every file it
deleted. If they still reference one when the budget expires, the fixture is
written back so the shared dev server keeps serving the rest of the suite, and
the hook fails naming the stranded path. The wait runs before the node_modules
fixture-package removal so a restored fixture still resolves its import.
The pre-e2e probe moves from `GET /api/chat` to
`POST /.well-known/workflow/v1/flow?__health`. /api/chat compiles independently
of the flow route, so it answered 405 in all three jobs while every dispatch
was getting a 500.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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changeset-botBot commented Aug 19, 2026•
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🦋 Changeset detected

Latest commit: d11c0dd

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 16 packages
NameType
@workflow/corePatch
@workflow/buildersPatch
@workflow/cliPatch
@workflow/nextPatch
@workflow/nitroPatch
@workflow/vitestPatch
@workflow/web-sharedPatch
@workflow/webPatch
workflowPatch
@workflow/world-testingPatch
@workflow/astroPatch
@workflow/nestPatch
@workflow/rollupPatch
@workflow/sveltekitPatch
@workflow/vitePatch
@workflow/nuxtPatch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

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🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

▲ Vercel Production (8 failed)

python-node (8 failed):

  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9 | 🔍 observability
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K | 🔍 observability
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1 | 🔍 observability
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C | 🔍 observability
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C | 🔍 observability
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV | 🔍 observability
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG | 🔍 observability
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP | 🔍 observability

🌐 Cross-language Conformance (9 failed)

python (9 failed):

  • deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0TYP4EWXS4MHWKXFZN1JR0F
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP

⚠️ Flaky E2E Tests (passed on retry)

These tests failed at least once and passed on a retry. A recurring entry here is a real race worth investigating.

  • addTenWorkflow (fastify)
  • addTenWorkflow (hono)
  • addTenWorkflow (nuxt)
  • cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
  • cancelRun via CLI - cancelling a running workflow (nuxt)
  • hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (nextjs-webpack)
  • hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (nextjs-webpack)
  • sleepWinsRaceWorkflow (tanstack-start)

🛠 Infra Events (absorbed by the harness)

Platform anomalies the e2e harness detected and worked around (e.g. a run the queue never picked up, replaced by a fresh run). Clustered timestamps indicate a backend blip; a steady drip indicates a platform issue worth escalating.

32 infra events
  • cold-start-warmup · suite warmup (python) · at 22:32:26Z · abandoned wrun_41M0TYAYJT0GNGCGFT9CW8J31C · (+7 more)
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN9
  • run-pickup-stall · nullByteWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKF10GW0JY2HGZZ2K8BR
  • run-pickup-stall · sleepingWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN8
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKTR0GSK8P4JGC50Q9YT
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:32:43Z · abandoned wrun_41M0TYEKEQ0GVKJ0FPW7DV5X07
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:33:15Z · abandoned wrun_41M0TYFKB30GZV9RYEXPSVWC4S
  • run-pickup-stall · sleepingWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYP0GNT5G4RBTCFB13K
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF3N0GT1E7GFW1V9TJ21
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYS0GY7C05YYWCVAN24
  • run-pickup-stall · nullByteWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF250GVD8T6M4BGNC9MZ
  • cold-start-warmup · suite warmup (tanstack-start) · at 22:34:07Z · abandoned wrun_01M0TYGV52206SC5AEK09QTHDV
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:34:33Z · abandoned wrun_41M0TYGK1Q0GP2X8Z95ZQRRF08
  • cold-start-warmup · suite warmup (python) · at 22:35:18Z · abandoned wrun_01M0TYG6112GWK343TTH7VNV7D · (+7 more)
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36E
  • run-pickup-stall · sleepingWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5VB4BEN37GS66N59YK
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5Y18NPGYQK6XKMNBJY
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36D
  • run-pickup-stall · nullByteWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV60YRZTH9DG0JNDANBH
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSJYNGNK851MQP1JB09
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSGB77J7W5E13A3R263
  • run-pickup-stall · sleepingWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSM1WW7VT6JAS9B0VEX
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSQ61EMZQSZ849JNHA7
  • run-pickup-stall · nullByteWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSR4ER537QZBJ79SN2G
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:36:55Z · abandoned wrun_41M0TYK6V80GQ8NYJDE1PPJBXH
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:36:55Z · abandoned wrun_41M0TYKAY70GYG61T79VHX87WA
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGD6NDH7M075CNB00CER
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDAM3PHNF2JA81T8P7Z
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDH2ZVXYM64QF0HSDRM
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRQC396P9TA2NFEF1YW
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRY07WYKZTT81X3CSEA
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:38:33Z · abandoned wrun_01M0TYSB0M52SKJN6P09C9FJ4R

E2E Test Summary

Summary
PassedFailedSkippedTotal
❌ ▲ Vercel Production357087424320
✅ 💻 Local Development392205584480
✅ 📦 Local Production392205584480
✅ 🐘 Local Postgres392205584480
✅ 🪟 Windows32000320
❌ 🌐 Cross-language Conformance09132141
✅ vercel-http-transport8170143960
✅ vercel-multi-region270027
✅ vercel-ws-transport553087640
Total1705317277819848
Details by Category

❌ ▲ Vercel Production

AppPassedFailedSkipped
✅ astro-node132028
✅ astro-quickjs132028
✅ example-node132028
✅ example-quickjs132028
✅ express-node132028
✅ express-quickjs132028
✅ fastify-node132028
✅ fastify-quickjs132028
✅ hono-node132028
✅ hono-quickjs132028
✅ nest-node132028
✅ nest-quickjs132028
✅ nextjs-turbopack-node15703
✅ nextjs-turbopack-quickjs15703
✅ nextjs-webpack-node15703
✅ nextjs-webpack-quickjs15703
✅ nitro-node132028
✅ nitro-quickjs132028
✅ nuxt-node132028
✅ nuxt-quickjs132028
❌ python-node08152
✅ sveltekit-node15109
✅ sveltekit-quickjs15109
✅ tanstack-start-node132028
✅ tanstack-start-quickjs132028
✅ vite-node132028
✅ vite-quickjs132028

✅ 💻 Local Development

AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026

✅ 📦 Local Production

AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026

✅ 🐘 Local Postgres

AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026

✅ 🪟 Windows

AppPassedFailedSkipped
✅ nextjs-turbopack-node16000
✅ nextjs-turbopack-quickjs16000

❌ 🌐 Cross-language Conformance

AppPassedFailedSkipped
❌ python09132

✅ vercel-http-transport

AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ hono132028
✅ nextjs-turbopack15703
✅ nitro132028
✅ vite132028

✅ vercel-multi-region

AppPassedFailedSkipped
✅ nextjs-turbopack2700

✅ vercel-ws-transport

AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ nextjs-turbopack15703
✅ vite132028

📋 View full workflow run

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📊 Workflow Benchmarks

commit d11c0dd · Mon, 24 Aug 2026 22:55:03 GMT · run logs

Backend: vercel · app: nextjs-turbopack

MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep246 (-75%) 💚1346 🔴 (+22%) 🔻1384 🔴 (+20%) 🔻1484 🔴 (+18%) 🔻30
TTFSstream222 (-69%) 💚1328 🔴 (+21%) 🔻1400 🔴 (+26%) 🔻1432 🔴 (+11%)30
TTFShook + stream1264 (-8.0%)1646 🔴 (+12%)1722 🔴 (+14%)2321 🔴 (+45%) 🔻30
Fan-out TTFSPromise.all(100 steps)645 (-0.8%)1882 (+10%)2135 (+19%) 🔻2343 (+20%) 🔻10
Fan-out TTLSPromise.all(100 steps)1841 (-4.7%)3816 (+20%) 🔻5084 (+55%) 🔻5570 (-34%) 💚10
STSO1020 steps (inline)69 (-34%) 💚140 (-5.4%)164 (-2.4%)275 (+26%) 🔻1019
WO1020 steps140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)1
CRTTfirst chunk (pooled)107 (+22%) 🔻171 (+38%) 🔻260 (+35%) 🔻274 (-56%) 💚28

Streams

ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+25%)256 (+97%)513 (+142%)967 (+27%)279 (+95%)10
size sweep (100/s, 160B-12KB)150 (+33%)164 (+15%)275 (+47%)495 (-56%)195 (+42%)10
replay gateway-gpt-5.4-nano-2000t (1x)131 (+7%)532 (-18%)706 (-79%)911 (-81%)203 (-6%)3
replay eve-gpt-5.6-sol-2000t (1x)216 (+83%)168 (+25%)261 (+54%)1122 (+225%)761 (+191%)2
replay eve-gpt-5.6-sol-2000t (2x)150 (+22%)207 (+13%)274 (+4%)691 (+25%)268 (+18%)3
📈 STSO distribution vs main (inline / queue-hop histograms)

1020 steps (inline)

Cumulative STSO time: main 147417ms → this run 140462ms (Δ -6955ms, -5%)

 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████░┃ main 785 this 848 +63
150-200 ms ███┃██ main 216 this 143 -73
200-250 ms ┃ main 14 this 11 -3
250-300 ms ┃ main 4 this 9 +5
300-350 ms ┃ main 0 this 5 +5
350-400 ms ┃ main 0 this 1 +1
400-450 ms ┃ main 0 this 1 +1
📈 CRTT drill-down vs main (RTT distributions & profiles)
variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▃█▃▁··· 175.1 (+46%) 135 (+27%) 513 (+142%) 967 (+27%) 3000
sweep ······▃█▂▁··· 136.8 (+11%) 122 (+11%) 275 (+47%) 495 (-56%) 3000
gw 1x ·····▁▄█▃▂··· 203.3 (-39%) 119 (+18%) 706 (-79%) 911 (-81%) 5295
eve 1x ·····▁▃█▂▁▁·· 171.8 (+55%) 129 (+42%) 261 (+54%) 1122 (+225%) 5186
eve 2x ·····▁▂█▃▁··· 167.7 (+20%) 149 (+16%) 274 (+4%) 691 (+25%) 7779

RTT over stream progress (avg per tenth of stream, bars scaled min→max):

control ▅█▄▆▃▄▁▆▅█ 145–199ms
sweep █▆▂▁▂▅▃▁▃▂ 116–178ms
gw 1x ██▄▄▅▁▂▄▇▅ 122–275ms
eve 1x ▂▂▃▂▁▁▄█▁▁ 121–326ms
eve 2x ▃▁▁▁▁▂▅██▂ 142–224ms

RTT by chunk size (avg per log size bin, ~160B → ~12KB serialized, bars scaled min→max):

sweep ▁▅█▅▅▂▃ 136–138ms

Delivery jitter over stream progress (avg positive CDV per tenth of stream, bars scaled min→max):

control ▄▁▁▆▆▃▆▄█▅ 34–56ms
sweep ▁▃▃▃▆▄▆▄█▂ 44–59ms
gw 1x █▄▂▂▃▁▄▃▆▃ 38–71ms
eve 1x ▅▆▆▅▃▁█▅▃▃ 24–39ms
eve 2x █▇▁▃▆▅█▃▄▆ 22–36ms
📜 Previous results (2)

47501c6

Fri, 21 Aug 2026 23:12:41 GMT · run logs

vercel / nextjs-turbopack

MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1314 (+22%) 🔻1396 🔴 (+21%) 🔻1428 🔴 (+14%)1481 🔴 (+3.6%)30
TTFSstream270 (-75%) 💚1352 🔴 (+12%)1378 🔴 (+7.1%)1389 🔴 (-3.9%)30
TTFShook + stream1534 (+45%) 🔻1659 🔴 (+14%)1766 🔴 (+17%) 🔻2433 🔴 (+57%) 🔻30
Fan-out TTFSPromise.all(100 steps)568 (-4.1%)2033 (+28%) 🔻2052 (+24%) 🔻2111 (+27%) 🔻10
Fan-out TTLSPromise.all(100 steps)1699 (+5.1%)3860 (+28%) 🔻4036 (+12%)4573 (+16%) 🔻10
STSO1020 steps (inline)114 (-24%) 💚168 (-24%) 💚189 (-27%) 💚344 (-36%) 💚1019
WO1020 steps169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚1
CRTTfirst chunk (pooled)99 (+4.2%)152 (+2.7%)189 (+8.6%)376 (+62%) 🔻28

Streams

ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+9%)143 (-23%)186 (-27%)402 (+6%)110 (-35%)10
size sweep (100/s, 160B-12KB)125 (+1%)151 (-18%)195 (-42%)279 (-46%)99.5 (-25%)10
replay gateway-gpt-5.4-nano-2000t (1x)152 (+26%)189 (-74%)414 (-87%)757 (-84%)466 (-86%)3
replay eve-gpt-5.6-sol-2000t (1x)159 (+31%)148 (-8%)186 (-10%)287 (-20%)296 (-2%)2
replay eve-gpt-5.6-sol-2000t (2x)135 (-13%)200 (-38%)268 (-73%)380 (-83%)246 (-38%)3

62fcd0f

Wed, 19 Aug 2026 23:10:40 GMT · run logs

vercel / nextjs-turbopack

MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1287 (+24%) 🔻1401 🔴 (+19%) 🔻1442 🔴 (+17%) 🔻1732 🔴 (+4.1%)30
TTFSstream1260 (+25%) 🔻1388 🔴 (+25%) 🔻1428 🔴 (+25%) 🔻1742 🔴 (+49%) 🔻30
TTFShook + stream538 (-58%) 💚1644 🔴 (+15%)1690 🔴 (+15%)1986 🔴 (+26%) 🔻30
Fan-out TTFSPromise.all(100 steps)527 (-7.9%)829 (-16%) 💚986 (-45%) 💚2498 (+38%) 🔻10
Fan-out TTLSPromise.all(100 steps)4804 (+1.2%)8742 (+6.0%)9471 (-13%)10733 (-19%) 💚10
STSO1020 steps (inline)117 (-5.6%)159 (-35%) 💚185 (-37%) 💚303 (-40%) 💚1019
WO1020 steps158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚1
CRTTfirst chunk (pooled)101 (-4.7%)175 (+3.6%)372 (+84%) 🔻3550 (+770%) 🔻28

Streams

ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)115 (-20%)131 (-27%)168 (-42%)335 (-36%)96.5 (-32%)10
size sweep (100/s, 160B-12KB)127 (-9%)135 (-26%)172 (-32%)310 (-31%)134 (-14%)10
replay gateway-gpt-5.4-nano-2000t (1x)204 (+37%)139 (-4%)230 (+8%)675 (-3%)293 (+18%)3
replay eve-gpt-5.6-sol-2000t (1x)1837 (+1128%)140 (-5%)193 (±0%)3960 (+1082%)2212 (+683%)2
replay eve-gpt-5.6-sol-2000t (2x)372 (+120%)242 (+12%)468 (+23%)1195 (±0%)226 (-43%)3
ℹ️ Metric definitions & methodology

Streams: first-chunk RTT (the stream-open path, before any buffering/backpressure), CRTT percentiles, and worst delivery stall (CDV max). Cells are medians across iterations; per-run values in the artifacts. No 🔴/🟢 marks until targets attach.

The collapsed STSO distribution section above buckets every step gap, split inline (same warm process — pure framework overhead) vs queue-hop (fresh process — dispatch, reinit, replay). █ = main, ┃ = this run, ░ = fill.

The collapsed CRTT drill-down: per-variant RTT histograms (fixed log bins, · = empty) and mean RTT/positive-CDV profile lines over stream progress and chunk size. Histograms, avgs, and profiles merge exactly across runs; p50–p99 are percentile-of-percentiles. Per-index rows live in the artifacts.

Best/P75/P90/P99 deltas compare against the most recent benchmark run on main at the time of this run. 🔻 flags a delta worse than +15%, 💚 one better than −15%.

Metrics — TTFS: time to first step body (in-deployment start() → first step body) · Fan-out TTFS: fan-out time to first step (in-deployment start() → first of the parallel step bodies to complete) · Fan-out TTLS: fan-out time to last step (in-deployment start() → last of the parallel step bodies to complete, i.e. when the Promise.all resolves) · STSO: step-to-step overhead (gap between consecutive step bodies) · WO: workflow overhead (whole-run time outside step bodies, in-deployment anchored) · CRTT: chunk round-trip time (per-chunk write → read latency, one clock domain: deployment → stream backend → same deployment) · CDV: chunk delay variation / delivery jitter (inter-arrival gap minus inter-write gap per seq-adjacent pair; skew-free; the row is each run's MAX positive value, so one stall moves it)

Scenarios — step: one trivial no-op step, no stream; no hooks, so the run stays in turbo mode (in-process fast path) · stream: one streaming step; no hooks, so the run stays in turbo mode (in-process fast path) · hook + stream: registers a hook before one step, which exits turbo mode (dispatch path) · 1020 steps: 1020 trivial sequential steps; STSO is measured between consecutive steps in the given step ranges, and WO is the whole-run overhead outside step bodies · Promise.all(100 steps): 100 trivial no-op steps started together in a single Promise.all; Fan-out TTFS is the first of them to complete and Fan-out TTLS the last, both from the in-deployment clientStart, so their gap is the spread the runtime adds across the fan-out · paced control (100/s, 60B): the control: 300 tiny (~60B) deltas metronome-paced at 100/s — zero workload structure, so it reads the transport floor and flush cadence, and disambiguates transport-wide vs workload-specific when a replay row moves · size sweep (100/s, 160B-12KB): same pacing as the control with deltas padded in rotation across seven log-spaced sizes (~160B–12KB) — rotation decouples size from stream position, so it isolates whether chunk size causes latency · replay gateway-gpt-5.4-nano-2000t (1x): raw provider SSE cadence captured at the AI gateway boundary (gpt-5.4-nano, the most popular gateway model; per-token deltas p50 208B = the modal production chunk size), replayed exactly as measured — the typical customer's workload; its CDV is the typical customer's real delivery jitter · replay eve-gpt-5.6-sol-2000t (1x): a captured eve turn (gpt-5.6-sol, the most-used demanding eve model; ~2000 output tokens = production p50 turn length) replayed exactly as measured — eve's envelope protocol re-ships the cumulative message so sizes ramp 142B→13KB; the demanding outlier tenant's reality · replay eve-gpt-5.6-sol-2000t (2x): the same eve capture at 2x — the headroom/stress row; real fast-tier models emit the same chunk sizes at proportionally higher rate, so time compression is a faithful speed model · first chunk (pooled): every run's seq-0 RTT pooled across all stream scenarios — the first chunk precedes any workload differentiation, so pooling samples one shared stream-open path with exact percentiles

Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000teaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041

🔴 marks a percentile over its target (within target is left unmarked). Targets (p75/p90/p99, ms) — TTFS 200/300/600

All timestamps are deployment-side; runs are triggered in-deployment, so the CI runner and api.vercel.com sit outside every measured window. TTFS = start() → first step body (includes dispatch + any cold start); Fan-out TTFS/TTLS = first/last step completion of one Promise.all from the same anchor (the gap is the runtime’s fan-out spread); STSO/WO between step bodies; CRTT inside the workflow (excludes the api.vercel.com read path).

Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.

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Sim World

Simulated world deterministic testing for races. Traces

🟠 world-sim scenario book — 1 fail of 41 total

fence=per-spec

scenariooutcomeeventsvirtreplayviolations
✅ smoke-no-stepscompleted30msok0
✅ smoke-one-stepcompleted60msok0
✅ hook-at-step-startedcompleted120msok0
✅ hook-at-step-completedcompleted120msok0
✅ hook-at-hook-createdcompleted120msok0
✅ deadline-hook-winscompleted71.0hok0
✅ deadline-expirescompleted71.0hok0
✅ long-sleepcompleted1130.0dok0
✅ hook-never-arrivesstalled30msskipped0
✅ step-retries-twicecompleted102.0sok0
✅ parallel-stepscompleted90msok0
✅ hook-on-execution-statecompleted120msok0
✅ peek-hook-before-branchcompleted120msok0
✅ peek-hook-after-branchcompleted120msok0
✅ peek-hook-at-registrationcompleted120msok0
✅ race-hook-before-probecompleted120msok0
✅ race-hook-after-probecompleted120msok0
✅ race-duplicate-deliverycompleted130msok0
✅ attr-hook-before-stepcompleted110msok0
✅ attr-hook-after-stepcompleted110msok0
✅ attr-from-step-bodycompleted130msok0
✅ fork-hook-after-timeoutcompleted141.0mok0
✅ fork-hook-before-timeoutcompleted141.0mok0
✅ count-hook-after-timeoutcompleted171.0mok0
✅ count-hook-before-timeoutcompleted201.0mok0
✅ stale-read-step-count-forkcompleted201.0mok0
✅ stale-read-equal-step-countscompleted141.0mok0
✅ step-vs-step-forkcompleted120msok0
✅ step-vs-step-fork-fencedcompleted120msok0
✅ fence-catches-benign-directioncompleted125msok0
✅ in-flight-before-decisioncompleted171.0mok0
❌ in-flight-before-decision-countedcompleted171.0mok0
✅ in-flight-after-decisioncompleted192.0mok0
✅ stale-read-step-count-fork-fencedcompleted201.0mok0
✅ fork-hook-winscompleted131.0mok0
✅ fork-timeout-winscompleted131.0mok0
✅ unclaimed-payload-under-forkcompleted171.0mok0
✅ claimed-payload-under-forkcompleted171.0mok0
✅ writers-independent-step-bodiescompleted120msok0
✅ writers-scripted-tempocompleted120msok0
✅ cancel-mid-stepcancelled70msskipped0

Full trace: world-sim.txt

@VaguelySerious
VaguelySerious marked this pull request as ready for review August 21, 2026 22:48
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VaguelySerious requested a review from a team as a code ownerAugust 21, 2026 22:48
@VaguelySerious
VaguelySerious merged commit 5841558 into mainAug 25, 2026
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@VaguelySerious
VaguelySerious deleted the peter/windows-step-registration-cleanup branch August 25, 2026 19:07
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No backport to stable for 5841558 (AI decision).

This is CI/test hardening for a failure mode that does not exist on stable: the generated __step_registrations.js that strands a deleted step fixture is main-only (on stable, step_registration appears only in the SWC plugin's Rust, and packages/next generates no such file), and the dev.test.ts changes build on main-only harness pieces (generatedStepRegistrationPath config, restoreDirectories). The tests.yml hunk likewise rewrites a Get-DevServerStatus pre-e2e probe block that stable does not have at all. Nothing here keeps stable buildable, testable, or releasable.

To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:

584155897f75e712a1c2bc199d6d12027cd18dab

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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
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}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
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try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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[core] Fail dev HMR cleanup on a stranded step registration - #3682
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[core] Fail dev HMR cleanup on a stranded step registration#3682
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Problem
Three of the last 120 Tests runs had E2E Windows Tests (node) burn its full ~30-minute

window and get cancelled with every e2e test failing on
[world-local] Queue message failed (HTTP 500), where the handlerError is a Next.js
_error page rather than anything workflow-shaped:
jobflow-route 500sstranded-import errors
9622825337310,13520,346
9621451553010,21810,886
9620285500910,28020,557
The flow route never answered a single request successfully in any of them. The dev server

log says why:
⨯ app/.well-known/workflow/v1/flow/__step_registrations.js:33:1
Module not found: Can't resolve '../../../../../workflows/source-map-warning-fixture.ts'

dev.test.ts > "should not log source map warnings for workflow node_modules imports"

writes workflows/source-map-warning-fixture.ts, which declares a 'use step' function,

and its afterEach deletes it. The generated __step_registrations.js imports every

discovered step file by path, so that deletion only stops breaking the flow route once a

rediscovery regenerates the file. When the watcher drops the unlink — which is what happens

on Windows — the generated file keeps importing a path that no longer exists, the flow route

stops compiling, and every workflow dispatch for the rest of the job gets a 500 pointing at

a fixture from a test that already passed.
The HMR log confirms nothing recovers it: 164 → 165 → 166 → 165 → 165 workflows, then

three skips and no further rediscovery. afterEach's prewarm() only waits for
workflow dev hmr: ready, printed once at startup, so nothing ever waited for the

post-deletion rediscovery in the first place.
The generated workflow bundle inlines workflow sources instead of importing them, so only
step-declaring fixtures can strand it. That is why new-workflow.ts leaks harmlessly in

the same runs while the source-map fixture is fatal.
The existing fail-fast guard cannot see this
The Windows job already probes the dev server before the long e2e run, precisely to avoid

burning the job window on a wedged server. It probes GET /api/chat, which compiles

independently of the flow route, so it reported -> 405 and let the suite run in all three

jobs.
Changes
  1. packages/core/e2e/dev.test.ts — after deleting fixtures, cleanup waits for the
    
generated step registrations to stop importing them. If they still do when the budget
    
runs out, the fixture contents are written back so the shared dev server keeps serving
    
the rest of the suite, and the hook fails naming the stranded file. CI already skips the
    
e2e suite when dev.test.ts fails, so this turns a 30-minute burn with ~10k misleading
    
500s into an immediate, accurate failure. The convergence wait runs before the
    node_modules fixture-package removal so a restored fixture still resolves its import.
  2. .github/workflows/tests.yml — the pre-e2e probe now POSTs
    /.well-known/workflow/v1/flow?__health, the SDK's own health endpoint on the route
    
that actually breaks. It returns 200 on a healthy dev server and would have returned 500
    
in all three jobs above.
Validation
Run locally against workbench/nextjs-turbopack on macOS (all 9 dev tests, so including

the flow-route HMR fuzz cases that also delete step-declaring files):
  • Happy path: the convergence wait never trips on any of the tests that delete fixtures. A
    
deletion converges in ~2s, so the watcher path itself is sound and the Windows miss is the
    
discriminator.
  • should follow Next flow-route HMR rebuild rules for body-only changes fails on macOS
    
(expected 2 to be 1 on an exact HMR log count). It fails identically with unmodified
    origin/main's dev.test.ts against the same dev server, so it is pre-existing and
    
unrelated. That case is skipped on Windows.
  • Forced-failure path (convergence budget shortened so it always expires): the hook fails
    
with the stranded path named, the fixture is restored, and
    POST /.well-known/workflow/v1/flow?__health still answers 200.
  • POST /.well-known/workflow/v1/flow?__health returns 200 on a healthy dev server and 500
    
when a path reachable from __step_registrations.js does not resolve, while
    GET /api/chat keeps answering 405 — the asymmetry the second change fixes.
The underlying Windows watcher miss is worth chasing separately; this PR stops it from

costing a whole job and makes it name itself.
Note on a related hole, not changed here
The Linux e2e-local-dev lane runs pnpm vitest run packages/core/e2e/dev.test.ts; sleep 10

and then continues into the full e2e suite, so a dev.test.ts failure there is discarded.

That lane would swallow the new hook failure too. Tightening it would newly red the lane on

pre-existing dev.test.ts flakes (the flow-route HMR fuzz case already fails on macOS

against unmodified main, see below), so it seemed worth raising separately rather than

bundling in.
@VaguelySerious@claude
[core] Fail dev HMR cleanup on a stranded step registration
62fcd0f
`dev.test.ts` fixtures that declare a `'use step'` function are imported by
path from the generated `__step_registrations.js`, so deleting one only stops
breaking the flow route once a rediscovery regenerates that file. When the dev
server's watcher drops the unlink, the generated file keeps importing a path
that no longer exists: the flow route stops compiling and every later workflow
dispatch in the job gets a 500 that names a fixture from a test that already
passed. Three of the last 120 `Tests` runs lost the whole ~30-minute Windows
e2e window this way, each with ~10k flow-route 500s and no successful dispatch.
Cleanup now waits for the generated step registrations to drop every file it
deleted. If they still reference one when the budget expires, the fixture is
written back so the shared dev server keeps serving the rest of the suite, and
the hook fails naming the stranded path. The wait runs before the node_modules
fixture-package removal so a restored fixture still resolves its import.
The pre-e2e probe moves from `GET /api/chat` to
`POST /.well-known/workflow/v1/flow?__health`. /api/chat compiles independently
of the flow route, so it answered 405 in all three jobs while every dispatch
was getting a 500.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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🦋 Changeset detected
Latest commit: d11c0dd
The changes in this PR will be included in the next version bump.
This PR includes changesets to release 16 packages
NameType
@workflow/corePatch
@workflow/buildersPatch
@workflow/cliPatch
@workflow/nextPatch
@workflow/nitroPatch
@workflow/vitestPatch
@workflow/web-sharedPatch
@workflow/webPatch
workflowPatch
@workflow/world-testingPatch
@workflow/astroPatch
@workflow/nestPatch
@workflow/rollupPatch
@workflow/sveltekitPatch
@workflow/vitePatch
@workflow/nuxtPatch
Not sure what this means? Click here to learn what changesets are.
Click here if you're a maintainer who wants to add another changeset to this PR
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🧪 E2E Test Results
❌ Some tests failed
❌ Failed E2E Tests
▲ Vercel Production (8 failed)
python-node (8 failed):
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9 | 🔍 observability
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K | 🔍 observability
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1 | 🔍 observability
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C | 🔍 observability
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C | 🔍 observability
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV | 🔍 observability
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG | 🔍 observability
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP | 🔍 observability
🌐 Cross-language Conformance (9 failed)
python (9 failed):
  • deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0TYP4EWXS4MHWKXFZN1JR0F
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP
⚠️ Flaky E2E Tests (passed on retry)
These tests failed at least once and passed on a retry. A recurring entry here is a real race worth investigating.
  • addTenWorkflow (fastify)
  • addTenWorkflow (hono)
  • addTenWorkflow (nuxt)
  • cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
  • cancelRun via CLI - cancelling a running workflow (nuxt)
  • hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (nextjs-webpack)
  • hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (nextjs-webpack)
  • sleepWinsRaceWorkflow (tanstack-start)
🛠 Infra Events (absorbed by the harness)
Platform anomalies the e2e harness detected and worked around (e.g. a run the queue never picked up, replaced by a fresh run). Clustered timestamps indicate a backend blip; a steady drip indicates a platform issue worth escalating.
32 infra events
  • cold-start-warmup · suite warmup (python) · at 22:32:26Z · abandoned wrun_41M0TYAYJT0GNGCGFT9CW8J31C · (+7 more)
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN9
  • run-pickup-stall · nullByteWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKF10GW0JY2HGZZ2K8BR
  • run-pickup-stall · sleepingWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN8
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKTR0GSK8P4JGC50Q9YT
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:32:43Z · abandoned wrun_41M0TYEKEQ0GVKJ0FPW7DV5X07
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:33:15Z · abandoned wrun_41M0TYFKB30GZV9RYEXPSVWC4S
  • run-pickup-stall · sleepingWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYP0GNT5G4RBTCFB13K
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF3N0GT1E7GFW1V9TJ21
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYS0GY7C05YYWCVAN24
  • run-pickup-stall · nullByteWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF250GVD8T6M4BGNC9MZ
  • cold-start-warmup · suite warmup (tanstack-start) · at 22:34:07Z · abandoned wrun_01M0TYGV52206SC5AEK09QTHDV
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:34:33Z · abandoned wrun_41M0TYGK1Q0GP2X8Z95ZQRRF08
  • cold-start-warmup · suite warmup (python) · at 22:35:18Z · abandoned wrun_01M0TYG6112GWK343TTH7VNV7D · (+7 more)
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36E
  • run-pickup-stall · sleepingWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5VB4BEN37GS66N59YK
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5Y18NPGYQK6XKMNBJY
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36D
  • run-pickup-stall · nullByteWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV60YRZTH9DG0JNDANBH
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSJYNGNK851MQP1JB09
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSGB77J7W5E13A3R263
  • run-pickup-stall · sleepingWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSM1WW7VT6JAS9B0VEX
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSQ61EMZQSZ849JNHA7
  • run-pickup-stall · nullByteWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSR4ER537QZBJ79SN2G
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:36:55Z · abandoned wrun_41M0TYK6V80GQ8NYJDE1PPJBXH
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:36:55Z · abandoned wrun_41M0TYKAY70GYG61T79VHX87WA
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGD6NDH7M075CNB00CER
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDAM3PHNF2JA81T8P7Z
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDH2ZVXYM64QF0HSDRM
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRQC396P9TA2NFEF1YW
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRY07WYKZTT81X3CSEA
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:38:33Z · abandoned wrun_01M0TYSB0M52SKJN6P09C9FJ4R
E2E Test Summary
Summary
PassedFailedSkippedTotal
❌ ▲ Vercel Production357087424320
✅ 💻 Local Development392205584480
✅ 📦 Local Production392205584480
✅ 🐘 Local Postgres392205584480
✅ 🪟 Windows32000320
❌ 🌐 Cross-language Conformance09132141
✅ vercel-http-transport8170143960
✅ vercel-multi-region270027
✅ vercel-ws-transport553087640
Total1705317277819848
Details by Category
❌ ▲ Vercel Production
AppPassedFailedSkipped
✅ astro-node132028
✅ astro-quickjs132028
✅ example-node132028
✅ example-quickjs132028
✅ express-node132028
✅ express-quickjs132028
✅ fastify-node132028
✅ fastify-quickjs132028
✅ hono-node132028
✅ hono-quickjs132028
✅ nest-node132028
✅ nest-quickjs132028
✅ nextjs-turbopack-node15703
✅ nextjs-turbopack-quickjs15703
✅ nextjs-webpack-node15703
✅ nextjs-webpack-quickjs15703
✅ nitro-node132028
✅ nitro-quickjs132028
✅ nuxt-node132028
✅ nuxt-quickjs132028
❌ python-node08152
✅ sveltekit-node15109
✅ sveltekit-quickjs15109
✅ tanstack-start-node132028
✅ tanstack-start-quickjs132028
✅ vite-node132028
✅ vite-quickjs132028
✅ 💻 Local Development
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 📦 Local Production
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🐘 Local Postgres
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🪟 Windows
AppPassedFailedSkipped
✅ nextjs-turbopack-node16000
✅ nextjs-turbopack-quickjs16000
❌ 🌐 Cross-language Conformance
AppPassedFailedSkipped
❌ python09132
✅ vercel-http-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ hono132028
✅ nextjs-turbopack15703
✅ nitro132028
✅ vite132028
✅ vercel-multi-region
AppPassedFailedSkipped
✅ nextjs-turbopack2700
✅ vercel-ws-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ nextjs-turbopack15703
✅ vite132028
📋 View full workflow run
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📊 Workflow Benchmarks
commit d11c0dd · Mon, 24 Aug 2026 22:55:03 GMT · run logs
Backend: vercel · app: nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep246 (-75%) 💚1346 🔴 (+22%) 🔻1384 🔴 (+20%) 🔻1484 🔴 (+18%) 🔻30
TTFSstream222 (-69%) 💚1328 🔴 (+21%) 🔻1400 🔴 (+26%) 🔻1432 🔴 (+11%)30
TTFShook + stream1264 (-8.0%)1646 🔴 (+12%)1722 🔴 (+14%)2321 🔴 (+45%) 🔻30
Fan-out TTFSPromise.all(100 steps)645 (-0.8%)1882 (+10%)2135 (+19%) 🔻2343 (+20%) 🔻10
Fan-out TTLSPromise.all(100 steps)1841 (-4.7%)3816 (+20%) 🔻5084 (+55%) 🔻5570 (-34%) 💚10
STSO1020 steps (inline)69 (-34%) 💚140 (-5.4%)164 (-2.4%)275 (+26%) 🔻1019
WO1020 steps140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)1
CRTTfirst chunk (pooled)107 (+22%) 🔻171 (+38%) 🔻260 (+35%) 🔻274 (-56%) 💚28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+25%)256 (+97%)513 (+142%)967 (+27%)279 (+95%)10
size sweep (100/s, 160B-12KB)150 (+33%)164 (+15%)275 (+47%)495 (-56%)195 (+42%)10
replay gateway-gpt-5.4-nano-2000t (1x)131 (+7%)532 (-18%)706 (-79%)911 (-81%)203 (-6%)3
replay eve-gpt-5.6-sol-2000t (1x)216 (+83%)168 (+25%)261 (+54%)1122 (+225%)761 (+191%)2
replay eve-gpt-5.6-sol-2000t (2x)150 (+22%)207 (+13%)274 (+4%)691 (+25%)268 (+18%)3
📈 STSO distribution vs main (inline / queue-hop histograms)
1020 steps (inline)
Cumulative STSO time: main 147417ms → this run 140462ms (Δ -6955ms, -5%)
 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████░┃ main 785 this 848 +63
150-200 ms ███┃██ main 216 this 143 -73
200-250 ms ┃ main 14 this 11 -3
250-300 ms ┃ main 4 this 9 +5
300-350 ms ┃ main 0 this 5 +5
350-400 ms ┃ main 0 this 1 +1
400-450 ms ┃ main 0 this 1 +1

📈 CRTT drill-down vs main (RTT distributions & profiles)
variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▃█▃▁··· 175.1 (+46%) 135 (+27%) 513 (+142%) 967 (+27%) 3000
sweep ······▃█▂▁··· 136.8 (+11%) 122 (+11%) 275 (+47%) 495 (-56%) 3000
gw 1x ·····▁▄█▃▂··· 203.3 (-39%) 119 (+18%) 706 (-79%) 911 (-81%) 5295
eve 1x ·····▁▃█▂▁▁·· 171.8 (+55%) 129 (+42%) 261 (+54%) 1122 (+225%) 5186
eve 2x ·····▁▂█▃▁··· 167.7 (+20%) 149 (+16%) 274 (+4%) 691 (+25%) 7779

RTT over stream progress (avg per tenth of stream, bars scaled min→max):
control ▅█▄▆▃▄▁▆▅█ 145–199ms
sweep █▆▂▁▂▅▃▁▃▂ 116–178ms
gw 1x ██▄▄▅▁▂▄▇▅ 122–275ms
eve 1x ▂▂▃▂▁▁▄█▁▁ 121–326ms
eve 2x ▃▁▁▁▁▂▅██▂ 142–224ms

RTT by chunk size (avg per log size bin, ~160B → ~12KB serialized, bars scaled min→max):
sweep ▁▅█▅▅▂▃ 136–138ms

Delivery jitter over stream progress (avg positive CDV per tenth of stream, bars scaled min→max):
control ▄▁▁▆▆▃▆▄█▅ 34–56ms
sweep ▁▃▃▃▆▄▆▄█▂ 44–59ms
gw 1x █▄▂▂▃▁▄▃▆▃ 38–71ms
eve 1x ▅▆▆▅▃▁█▅▃▃ 24–39ms
eve 2x █▇▁▃▆▅█▃▄▆ 22–36ms

📜 Previous results (2)
47501c6
Fri, 21 Aug 2026 23:12:41 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1314 (+22%) 🔻1396 🔴 (+21%) 🔻1428 🔴 (+14%)1481 🔴 (+3.6%)30
TTFSstream270 (-75%) 💚1352 🔴 (+12%)1378 🔴 (+7.1%)1389 🔴 (-3.9%)30
TTFShook + stream1534 (+45%) 🔻1659 🔴 (+14%)1766 🔴 (+17%) 🔻2433 🔴 (+57%) 🔻30
Fan-out TTFSPromise.all(100 steps)568 (-4.1%)2033 (+28%) 🔻2052 (+24%) 🔻2111 (+27%) 🔻10
Fan-out TTLSPromise.all(100 steps)1699 (+5.1%)3860 (+28%) 🔻4036 (+12%)4573 (+16%) 🔻10
STSO1020 steps (inline)114 (-24%) 💚168 (-24%) 💚189 (-27%) 💚344 (-36%) 💚1019
WO1020 steps169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚1
CRTTfirst chunk (pooled)99 (+4.2%)152 (+2.7%)189 (+8.6%)376 (+62%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+9%)143 (-23%)186 (-27%)402 (+6%)110 (-35%)10
size sweep (100/s, 160B-12KB)125 (+1%)151 (-18%)195 (-42%)279 (-46%)99.5 (-25%)10
replay gateway-gpt-5.4-nano-2000t (1x)152 (+26%)189 (-74%)414 (-87%)757 (-84%)466 (-86%)3
replay eve-gpt-5.6-sol-2000t (1x)159 (+31%)148 (-8%)186 (-10%)287 (-20%)296 (-2%)2
replay eve-gpt-5.6-sol-2000t (2x)135 (-13%)200 (-38%)268 (-73%)380 (-83%)246 (-38%)3
62fcd0f
Wed, 19 Aug 2026 23:10:40 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1287 (+24%) 🔻1401 🔴 (+19%) 🔻1442 🔴 (+17%) 🔻1732 🔴 (+4.1%)30
TTFSstream1260 (+25%) 🔻1388 🔴 (+25%) 🔻1428 🔴 (+25%) 🔻1742 🔴 (+49%) 🔻30
TTFShook + stream538 (-58%) 💚1644 🔴 (+15%)1690 🔴 (+15%)1986 🔴 (+26%) 🔻30
Fan-out TTFSPromise.all(100 steps)527 (-7.9%)829 (-16%) 💚986 (-45%) 💚2498 (+38%) 🔻10
Fan-out TTLSPromise.all(100 steps)4804 (+1.2%)8742 (+6.0%)9471 (-13%)10733 (-19%) 💚10
STSO1020 steps (inline)117 (-5.6%)159 (-35%) 💚185 (-37%) 💚303 (-40%) 💚1019
WO1020 steps158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚1
CRTTfirst chunk (pooled)101 (-4.7%)175 (+3.6%)372 (+84%) 🔻3550 (+770%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)115 (-20%)131 (-27%)168 (-42%)335 (-36%)96.5 (-32%)10
size sweep (100/s, 160B-12KB)127 (-9%)135 (-26%)172 (-32%)310 (-31%)134 (-14%)10
replay gateway-gpt-5.4-nano-2000t (1x)204 (+37%)139 (-4%)230 (+8%)675 (-3%)293 (+18%)3
replay eve-gpt-5.6-sol-2000t (1x)1837 (+1128%)140 (-5%)193 (±0%)3960 (+1082%)2212 (+683%)2
replay eve-gpt-5.6-sol-2000t (2x)372 (+120%)242 (+12%)468 (+23%)1195 (±0%)226 (-43%)3
ℹ️ Metric definitions & methodology
Streams: first-chunk RTT (the stream-open path, before any buffering/backpressure), CRTT percentiles, and worst delivery stall (CDV max). Cells are medians across iterations; per-run values in the artifacts. No 🔴/🟢 marks until targets attach.
The collapsed STSO distribution section above buckets every step gap, split inline (same warm process — pure framework overhead) vs queue-hop (fresh process — dispatch, reinit, replay). █ = main, ┃ = this run, ░ = fill.
The collapsed CRTT drill-down: per-variant RTT histograms (fixed log bins, · = empty) and mean RTT/positive-CDV profile lines over stream progress and chunk size. Histograms, avgs, and profiles merge exactly across runs; p50–p99 are percentile-of-percentiles. Per-index rows live in the artifacts.
Best/P75/P90/P99 deltas compare against the most recent benchmark run on main at the time of this run. 🔻 flags a delta worse than +15%, 💚 one better than −15%.
Metrics — TTFS: time to first step body (in-deployment start() → first step body) · Fan-out TTFS: fan-out time to first step (in-deployment start() → first of the parallel step bodies to complete) · Fan-out TTLS: fan-out time to last step (in-deployment start() → last of the parallel step bodies to complete, i.e. when the Promise.all resolves) · STSO: step-to-step overhead (gap between consecutive step bodies) · WO: workflow overhead (whole-run time outside step bodies, in-deployment anchored) · CRTT: chunk round-trip time (per-chunk write → read latency, one clock domain: deployment → stream backend → same deployment) · CDV: chunk delay variation / delivery jitter (inter-arrival gap minus inter-write gap per seq-adjacent pair; skew-free; the row is each run's MAX positive value, so one stall moves it)
Scenarios — step: one trivial no-op step, no stream; no hooks, so the run stays in turbo mode (in-process fast path) · stream: one streaming step; no hooks, so the run stays in turbo mode (in-process fast path) · hook + stream: registers a hook before one step, which exits turbo mode (dispatch path) · 1020 steps: 1020 trivial sequential steps; STSO is measured between consecutive steps in the given step ranges, and WO is the whole-run overhead outside step bodies · Promise.all(100 steps): 100 trivial no-op steps started together in a single Promise.all; Fan-out TTFS is the first of them to complete and Fan-out TTLS the last, both from the in-deployment clientStart, so their gap is the spread the runtime adds across the fan-out · paced control (100/s, 60B): the control: 300 tiny (~60B) deltas metronome-paced at 100/s — zero workload structure, so it reads the transport floor and flush cadence, and disambiguates transport-wide vs workload-specific when a replay row moves · size sweep (100/s, 160B-12KB): same pacing as the control with deltas padded in rotation across seven log-spaced sizes (~160B–12KB) — rotation decouples size from stream position, so it isolates whether chunk size causes latency · replay gateway-gpt-5.4-nano-2000t (1x): raw provider SSE cadence captured at the AI gateway boundary (gpt-5.4-nano, the most popular gateway model; per-token deltas p50 208B = the modal production chunk size), replayed exactly as measured — the typical customer's workload; its CDV is the typical customer's real delivery jitter · replay eve-gpt-5.6-sol-2000t (1x): a captured eve turn (gpt-5.6-sol, the most-used demanding eve model; ~2000 output tokens = production p50 turn length) replayed exactly as measured — eve's envelope protocol re-ships the cumulative message so sizes ramp 142B→13KB; the demanding outlier tenant's reality · replay eve-gpt-5.6-sol-2000t (2x): the same eve capture at 2x — the headroom/stress row; real fast-tier models emit the same chunk sizes at proportionally higher rate, so time compression is a faithful speed model · first chunk (pooled): every run's seq-0 RTT pooled across all stream scenarios — the first chunk precedes any workload differentiation, so pooling samples one shared stream-open path with exact percentiles
Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000teaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041
🔴 marks a percentile over its target (within target is left unmarked). Targets (p75/p90/p99, ms) — TTFS 200/300/600
All timestamps are deployment-side; runs are triggered in-deployment, so the CI runner and api.vercel.com sit outside every measured window. TTFS = start() → first step body (includes dispatch + any cold start); Fan-out TTFS/TTLS = first/last step completion of one Promise.all from the same anchor (the gap is the runtime’s fan-out spread); STSO/WO between step bodies; CRTT inside the workflow (excludes the api.vercel.com read path).
Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.
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Sim World
Simulated world deterministic testing for races. Traces
🟠 world-sim scenario book — 1 fail of 41 total
fence=per-spec
scenariooutcomeeventsvirtreplayviolations
✅ smoke-no-stepscompleted30msok0
✅ smoke-one-stepcompleted60msok0
✅ hook-at-step-startedcompleted120msok0
✅ hook-at-step-completedcompleted120msok0
✅ hook-at-hook-createdcompleted120msok0
✅ deadline-hook-winscompleted71.0hok0
✅ deadline-expirescompleted71.0hok0
✅ long-sleepcompleted1130.0dok0
✅ hook-never-arrivesstalled30msskipped0
✅ step-retries-twicecompleted102.0sok0
✅ parallel-stepscompleted90msok0
✅ hook-on-execution-statecompleted120msok0
✅ peek-hook-before-branchcompleted120msok0
✅ peek-hook-after-branchcompleted120msok0
✅ peek-hook-at-registrationcompleted120msok0
✅ race-hook-before-probecompleted120msok0
✅ race-hook-after-probecompleted120msok0
✅ race-duplicate-deliverycompleted130msok0
✅ attr-hook-before-stepcompleted110msok0
✅ attr-hook-after-stepcompleted110msok0
✅ attr-from-step-bodycompleted130msok0
✅ fork-hook-after-timeoutcompleted141.0mok0
✅ fork-hook-before-timeoutcompleted141.0mok0
✅ count-hook-after-timeoutcompleted171.0mok0
✅ count-hook-before-timeoutcompleted201.0mok0
✅ stale-read-step-count-forkcompleted201.0mok0
✅ stale-read-equal-step-countscompleted141.0mok0
✅ step-vs-step-forkcompleted120msok0
✅ step-vs-step-fork-fencedcompleted120msok0
✅ fence-catches-benign-directioncompleted125msok0
✅ in-flight-before-decisioncompleted171.0mok0
❌ in-flight-before-decision-countedcompleted171.0mok0
✅ in-flight-after-decisioncompleted192.0mok0
✅ stale-read-step-count-fork-fencedcompleted201.0mok0
✅ fork-hook-winscompleted131.0mok0
✅ fork-timeout-winscompleted131.0mok0
✅ unclaimed-payload-under-forkcompleted171.0mok0
✅ claimed-payload-under-forkcompleted171.0mok0
✅ writers-independent-step-bodiescompleted120msok0
✅ writers-scripted-tempocompleted120msok0
✅ cancel-mid-stepcancelled70msskipped0
Full trace: world-sim.txt
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peter/windows-step-registration-cleanup

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August 25, 2026 19:07
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No backport to stable for 5841558 (AI decision).
This is CI/test hardening for a failure mode that does not exist on stable: the generated __step_registrations.js that strands a deleted step fixture is main-only (on stable, step_registration appears only in the SWC plugin's Rust, and packages/next generates no such file), and the dev.test.ts changes build on main-only harness pieces (generatedStepRegistrationPath config, restoreDirectories). The tests.yml hunk likewise rewrites a Get-DevServerStatus pre-e2e probe block that stable does not have at all. Nothing here keeps stable buildable, testable, or releasable.
To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:
584155897f75e712a1c2bc199d6d12027cd18dab

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injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
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try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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[core] Fail dev HMR cleanup on a stranded step registration - #3682
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[core] Fail dev HMR cleanup on a stranded step registration#3682
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Problem
Three of the last 120 Tests runs had E2E Windows Tests (node) burn its full ~30-minute

window and get cancelled with every e2e test failing on
[world-local] Queue message failed (HTTP 500), where the handlerError is a Next.js
_error page rather than anything workflow-shaped:
jobflow-route 500sstranded-import errors
9622825337310,13520,346
9621451553010,21810,886
9620285500910,28020,557
The flow route never answered a single request successfully in any of them. The dev server

log says why:
⨯ app/.well-known/workflow/v1/flow/__step_registrations.js:33:1
Module not found: Can't resolve '../../../../../workflows/source-map-warning-fixture.ts'

dev.test.ts > "should not log source map warnings for workflow node_modules imports"

writes workflows/source-map-warning-fixture.ts, which declares a 'use step' function,

and its afterEach deletes it. The generated __step_registrations.js imports every

discovered step file by path, so that deletion only stops breaking the flow route once a

rediscovery regenerates the file. When the watcher drops the unlink — which is what happens

on Windows — the generated file keeps importing a path that no longer exists, the flow route

stops compiling, and every workflow dispatch for the rest of the job gets a 500 pointing at

a fixture from a test that already passed.
The HMR log confirms nothing recovers it: 164 → 165 → 166 → 165 → 165 workflows, then

three skips and no further rediscovery. afterEach's prewarm() only waits for
workflow dev hmr: ready, printed once at startup, so nothing ever waited for the

post-deletion rediscovery in the first place.
The generated workflow bundle inlines workflow sources instead of importing them, so only
step-declaring fixtures can strand it. That is why new-workflow.ts leaks harmlessly in

the same runs while the source-map fixture is fatal.
The existing fail-fast guard cannot see this
The Windows job already probes the dev server before the long e2e run, precisely to avoid

burning the job window on a wedged server. It probes GET /api/chat, which compiles

independently of the flow route, so it reported -> 405 and let the suite run in all three

jobs.
Changes
  1. packages/core/e2e/dev.test.ts — after deleting fixtures, cleanup waits for the
    
generated step registrations to stop importing them. If they still do when the budget
    
runs out, the fixture contents are written back so the shared dev server keeps serving
    
the rest of the suite, and the hook fails naming the stranded file. CI already skips the
    
e2e suite when dev.test.ts fails, so this turns a 30-minute burn with ~10k misleading
    
500s into an immediate, accurate failure. The convergence wait runs before the
    node_modules fixture-package removal so a restored fixture still resolves its import.
  2. .github/workflows/tests.yml — the pre-e2e probe now POSTs
    /.well-known/workflow/v1/flow?__health, the SDK's own health endpoint on the route
    
that actually breaks. It returns 200 on a healthy dev server and would have returned 500
    
in all three jobs above.
Validation
Run locally against workbench/nextjs-turbopack on macOS (all 9 dev tests, so including

the flow-route HMR fuzz cases that also delete step-declaring files):
  • Happy path: the convergence wait never trips on any of the tests that delete fixtures. A
    
deletion converges in ~2s, so the watcher path itself is sound and the Windows miss is the
    
discriminator.
  • should follow Next flow-route HMR rebuild rules for body-only changes fails on macOS
    
(expected 2 to be 1 on an exact HMR log count). It fails identically with unmodified
    origin/main's dev.test.ts against the same dev server, so it is pre-existing and
    
unrelated. That case is skipped on Windows.
  • Forced-failure path (convergence budget shortened so it always expires): the hook fails
    
with the stranded path named, the fixture is restored, and
    POST /.well-known/workflow/v1/flow?__health still answers 200.
  • POST /.well-known/workflow/v1/flow?__health returns 200 on a healthy dev server and 500
    
when a path reachable from __step_registrations.js does not resolve, while
    GET /api/chat keeps answering 405 — the asymmetry the second change fixes.
The underlying Windows watcher miss is worth chasing separately; this PR stops it from

costing a whole job and makes it name itself.
Note on a related hole, not changed here
The Linux e2e-local-dev lane runs pnpm vitest run packages/core/e2e/dev.test.ts; sleep 10

and then continues into the full e2e suite, so a dev.test.ts failure there is discarded.

That lane would swallow the new hook failure too. Tightening it would newly red the lane on

pre-existing dev.test.ts flakes (the flow-route HMR fuzz case already fails on macOS

against unmodified main, see below), so it seemed worth raising separately rather than

bundling in.
@VaguelySerious@claude
[core] Fail dev HMR cleanup on a stranded step registration
62fcd0f
`dev.test.ts` fixtures that declare a `'use step'` function are imported by
path from the generated `__step_registrations.js`, so deleting one only stops
breaking the flow route once a rediscovery regenerates that file. When the dev
server's watcher drops the unlink, the generated file keeps importing a path
that no longer exists: the flow route stops compiling and every later workflow
dispatch in the job gets a 500 that names a fixture from a test that already
passed. Three of the last 120 `Tests` runs lost the whole ~30-minute Windows
e2e window this way, each with ~10k flow-route 500s and no successful dispatch.
Cleanup now waits for the generated step registrations to drop every file it
deleted. If they still reference one when the budget expires, the fixture is
written back so the shared dev server keeps serving the rest of the suite, and
the hook fails naming the stranded path. The wait runs before the node_modules
fixture-package removal so a restored fixture still resolves its import.
The pre-e2e probe moves from `GET /api/chat` to
`POST /.well-known/workflow/v1/flow?__health`. /api/chat compiles independently
of the flow route, so it answered 405 in all three jobs while every dispatch
was getting a 500.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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🦋 Changeset detected
Latest commit: d11c0dd
The changes in this PR will be included in the next version bump.
This PR includes changesets to release 16 packages
NameType
@workflow/corePatch
@workflow/buildersPatch
@workflow/cliPatch
@workflow/nextPatch
@workflow/nitroPatch
@workflow/vitestPatch
@workflow/web-sharedPatch
@workflow/webPatch
workflowPatch
@workflow/world-testingPatch
@workflow/astroPatch
@workflow/nestPatch
@workflow/rollupPatch
@workflow/sveltekitPatch
@workflow/vitePatch
@workflow/nuxtPatch
Not sure what this means? Click here to learn what changesets are.
Click here if you're a maintainer who wants to add another changeset to this PR
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The latest updates on your projects. Learn more about Vercel for GitHub.
ProjectDeploymentActionsUpdated (UTC)
example-nextjs-workflow-turbopackReadyReadyPreview, v0Aug 24, 2026 10:33pm
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workbench-express-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-fastify-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
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🧪 E2E Test Results
❌ Some tests failed
❌ Failed E2E Tests
▲ Vercel Production (8 failed)
python-node (8 failed):
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9 | 🔍 observability
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K | 🔍 observability
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1 | 🔍 observability
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C | 🔍 observability
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C | 🔍 observability
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV | 🔍 observability
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG | 🔍 observability
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP | 🔍 observability
🌐 Cross-language Conformance (9 failed)
python (9 failed):
  • deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0TYP4EWXS4MHWKXFZN1JR0F
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP
⚠️ Flaky E2E Tests (passed on retry)
These tests failed at least once and passed on a retry. A recurring entry here is a real race worth investigating.
  • addTenWorkflow (fastify)
  • addTenWorkflow (hono)
  • addTenWorkflow (nuxt)
  • cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
  • cancelRun via CLI - cancelling a running workflow (nuxt)
  • hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (nextjs-webpack)
  • hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (nextjs-webpack)
  • sleepWinsRaceWorkflow (tanstack-start)
🛠 Infra Events (absorbed by the harness)
Platform anomalies the e2e harness detected and worked around (e.g. a run the queue never picked up, replaced by a fresh run). Clustered timestamps indicate a backend blip; a steady drip indicates a platform issue worth escalating.
32 infra events
  • cold-start-warmup · suite warmup (python) · at 22:32:26Z · abandoned wrun_41M0TYAYJT0GNGCGFT9CW8J31C · (+7 more)
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN9
  • run-pickup-stall · nullByteWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKF10GW0JY2HGZZ2K8BR
  • run-pickup-stall · sleepingWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN8
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKTR0GSK8P4JGC50Q9YT
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:32:43Z · abandoned wrun_41M0TYEKEQ0GVKJ0FPW7DV5X07
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:33:15Z · abandoned wrun_41M0TYFKB30GZV9RYEXPSVWC4S
  • run-pickup-stall · sleepingWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYP0GNT5G4RBTCFB13K
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF3N0GT1E7GFW1V9TJ21
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYS0GY7C05YYWCVAN24
  • run-pickup-stall · nullByteWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF250GVD8T6M4BGNC9MZ
  • cold-start-warmup · suite warmup (tanstack-start) · at 22:34:07Z · abandoned wrun_01M0TYGV52206SC5AEK09QTHDV
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:34:33Z · abandoned wrun_41M0TYGK1Q0GP2X8Z95ZQRRF08
  • cold-start-warmup · suite warmup (python) · at 22:35:18Z · abandoned wrun_01M0TYG6112GWK343TTH7VNV7D · (+7 more)
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36E
  • run-pickup-stall · sleepingWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5VB4BEN37GS66N59YK
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5Y18NPGYQK6XKMNBJY
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36D
  • run-pickup-stall · nullByteWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV60YRZTH9DG0JNDANBH
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSJYNGNK851MQP1JB09
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSGB77J7W5E13A3R263
  • run-pickup-stall · sleepingWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSM1WW7VT6JAS9B0VEX
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSQ61EMZQSZ849JNHA7
  • run-pickup-stall · nullByteWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSR4ER537QZBJ79SN2G
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:36:55Z · abandoned wrun_41M0TYK6V80GQ8NYJDE1PPJBXH
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:36:55Z · abandoned wrun_41M0TYKAY70GYG61T79VHX87WA
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGD6NDH7M075CNB00CER
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDAM3PHNF2JA81T8P7Z
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDH2ZVXYM64QF0HSDRM
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRQC396P9TA2NFEF1YW
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRY07WYKZTT81X3CSEA
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:38:33Z · abandoned wrun_01M0TYSB0M52SKJN6P09C9FJ4R
E2E Test Summary
Summary
PassedFailedSkippedTotal
❌ ▲ Vercel Production357087424320
✅ 💻 Local Development392205584480
✅ 📦 Local Production392205584480
✅ 🐘 Local Postgres392205584480
✅ 🪟 Windows32000320
❌ 🌐 Cross-language Conformance09132141
✅ vercel-http-transport8170143960
✅ vercel-multi-region270027
✅ vercel-ws-transport553087640
Total1705317277819848
Details by Category
❌ ▲ Vercel Production
AppPassedFailedSkipped
✅ astro-node132028
✅ astro-quickjs132028
✅ example-node132028
✅ example-quickjs132028
✅ express-node132028
✅ express-quickjs132028
✅ fastify-node132028
✅ fastify-quickjs132028
✅ hono-node132028
✅ hono-quickjs132028
✅ nest-node132028
✅ nest-quickjs132028
✅ nextjs-turbopack-node15703
✅ nextjs-turbopack-quickjs15703
✅ nextjs-webpack-node15703
✅ nextjs-webpack-quickjs15703
✅ nitro-node132028
✅ nitro-quickjs132028
✅ nuxt-node132028
✅ nuxt-quickjs132028
❌ python-node08152
✅ sveltekit-node15109
✅ sveltekit-quickjs15109
✅ tanstack-start-node132028
✅ tanstack-start-quickjs132028
✅ vite-node132028
✅ vite-quickjs132028
✅ 💻 Local Development
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 📦 Local Production
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🐘 Local Postgres
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🪟 Windows
AppPassedFailedSkipped
✅ nextjs-turbopack-node16000
✅ nextjs-turbopack-quickjs16000
❌ 🌐 Cross-language Conformance
AppPassedFailedSkipped
❌ python09132
✅ vercel-http-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ hono132028
✅ nextjs-turbopack15703
✅ nitro132028
✅ vite132028
✅ vercel-multi-region
AppPassedFailedSkipped
✅ nextjs-turbopack2700
✅ vercel-ws-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ nextjs-turbopack15703
✅ vite132028
📋 View full workflow run
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📊 Workflow Benchmarks
commit d11c0dd · Mon, 24 Aug 2026 22:55:03 GMT · run logs
Backend: vercel · app: nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep246 (-75%) 💚1346 🔴 (+22%) 🔻1384 🔴 (+20%) 🔻1484 🔴 (+18%) 🔻30
TTFSstream222 (-69%) 💚1328 🔴 (+21%) 🔻1400 🔴 (+26%) 🔻1432 🔴 (+11%)30
TTFShook + stream1264 (-8.0%)1646 🔴 (+12%)1722 🔴 (+14%)2321 🔴 (+45%) 🔻30
Fan-out TTFSPromise.all(100 steps)645 (-0.8%)1882 (+10%)2135 (+19%) 🔻2343 (+20%) 🔻10
Fan-out TTLSPromise.all(100 steps)1841 (-4.7%)3816 (+20%) 🔻5084 (+55%) 🔻5570 (-34%) 💚10
STSO1020 steps (inline)69 (-34%) 💚140 (-5.4%)164 (-2.4%)275 (+26%) 🔻1019
WO1020 steps140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)1
CRTTfirst chunk (pooled)107 (+22%) 🔻171 (+38%) 🔻260 (+35%) 🔻274 (-56%) 💚28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+25%)256 (+97%)513 (+142%)967 (+27%)279 (+95%)10
size sweep (100/s, 160B-12KB)150 (+33%)164 (+15%)275 (+47%)495 (-56%)195 (+42%)10
replay gateway-gpt-5.4-nano-2000t (1x)131 (+7%)532 (-18%)706 (-79%)911 (-81%)203 (-6%)3
replay eve-gpt-5.6-sol-2000t (1x)216 (+83%)168 (+25%)261 (+54%)1122 (+225%)761 (+191%)2
replay eve-gpt-5.6-sol-2000t (2x)150 (+22%)207 (+13%)274 (+4%)691 (+25%)268 (+18%)3
📈 STSO distribution vs main (inline / queue-hop histograms)
1020 steps (inline)
Cumulative STSO time: main 147417ms → this run 140462ms (Δ -6955ms, -5%)
 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████░┃ main 785 this 848 +63
150-200 ms ███┃██ main 216 this 143 -73
200-250 ms ┃ main 14 this 11 -3
250-300 ms ┃ main 4 this 9 +5
300-350 ms ┃ main 0 this 5 +5
350-400 ms ┃ main 0 this 1 +1
400-450 ms ┃ main 0 this 1 +1

📈 CRTT drill-down vs main (RTT distributions & profiles)
variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▃█▃▁··· 175.1 (+46%) 135 (+27%) 513 (+142%) 967 (+27%) 3000
sweep ······▃█▂▁··· 136.8 (+11%) 122 (+11%) 275 (+47%) 495 (-56%) 3000
gw 1x ·····▁▄█▃▂··· 203.3 (-39%) 119 (+18%) 706 (-79%) 911 (-81%) 5295
eve 1x ·····▁▃█▂▁▁·· 171.8 (+55%) 129 (+42%) 261 (+54%) 1122 (+225%) 5186
eve 2x ·····▁▂█▃▁··· 167.7 (+20%) 149 (+16%) 274 (+4%) 691 (+25%) 7779

RTT over stream progress (avg per tenth of stream, bars scaled min→max):
control ▅█▄▆▃▄▁▆▅█ 145–199ms
sweep █▆▂▁▂▅▃▁▃▂ 116–178ms
gw 1x ██▄▄▅▁▂▄▇▅ 122–275ms
eve 1x ▂▂▃▂▁▁▄█▁▁ 121–326ms
eve 2x ▃▁▁▁▁▂▅██▂ 142–224ms

RTT by chunk size (avg per log size bin, ~160B → ~12KB serialized, bars scaled min→max):
sweep ▁▅█▅▅▂▃ 136–138ms

Delivery jitter over stream progress (avg positive CDV per tenth of stream, bars scaled min→max):
control ▄▁▁▆▆▃▆▄█▅ 34–56ms
sweep ▁▃▃▃▆▄▆▄█▂ 44–59ms
gw 1x █▄▂▂▃▁▄▃▆▃ 38–71ms
eve 1x ▅▆▆▅▃▁█▅▃▃ 24–39ms
eve 2x █▇▁▃▆▅█▃▄▆ 22–36ms

📜 Previous results (2)
47501c6
Fri, 21 Aug 2026 23:12:41 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1314 (+22%) 🔻1396 🔴 (+21%) 🔻1428 🔴 (+14%)1481 🔴 (+3.6%)30
TTFSstream270 (-75%) 💚1352 🔴 (+12%)1378 🔴 (+7.1%)1389 🔴 (-3.9%)30
TTFShook + stream1534 (+45%) 🔻1659 🔴 (+14%)1766 🔴 (+17%) 🔻2433 🔴 (+57%) 🔻30
Fan-out TTFSPromise.all(100 steps)568 (-4.1%)2033 (+28%) 🔻2052 (+24%) 🔻2111 (+27%) 🔻10
Fan-out TTLSPromise.all(100 steps)1699 (+5.1%)3860 (+28%) 🔻4036 (+12%)4573 (+16%) 🔻10
STSO1020 steps (inline)114 (-24%) 💚168 (-24%) 💚189 (-27%) 💚344 (-36%) 💚1019
WO1020 steps169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚1
CRTTfirst chunk (pooled)99 (+4.2%)152 (+2.7%)189 (+8.6%)376 (+62%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+9%)143 (-23%)186 (-27%)402 (+6%)110 (-35%)10
size sweep (100/s, 160B-12KB)125 (+1%)151 (-18%)195 (-42%)279 (-46%)99.5 (-25%)10
replay gateway-gpt-5.4-nano-2000t (1x)152 (+26%)189 (-74%)414 (-87%)757 (-84%)466 (-86%)3
replay eve-gpt-5.6-sol-2000t (1x)159 (+31%)148 (-8%)186 (-10%)287 (-20%)296 (-2%)2
replay eve-gpt-5.6-sol-2000t (2x)135 (-13%)200 (-38%)268 (-73%)380 (-83%)246 (-38%)3
62fcd0f
Wed, 19 Aug 2026 23:10:40 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1287 (+24%) 🔻1401 🔴 (+19%) 🔻1442 🔴 (+17%) 🔻1732 🔴 (+4.1%)30
TTFSstream1260 (+25%) 🔻1388 🔴 (+25%) 🔻1428 🔴 (+25%) 🔻1742 🔴 (+49%) 🔻30
TTFShook + stream538 (-58%) 💚1644 🔴 (+15%)1690 🔴 (+15%)1986 🔴 (+26%) 🔻30
Fan-out TTFSPromise.all(100 steps)527 (-7.9%)829 (-16%) 💚986 (-45%) 💚2498 (+38%) 🔻10
Fan-out TTLSPromise.all(100 steps)4804 (+1.2%)8742 (+6.0%)9471 (-13%)10733 (-19%) 💚10
STSO1020 steps (inline)117 (-5.6%)159 (-35%) 💚185 (-37%) 💚303 (-40%) 💚1019
WO1020 steps158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚1
CRTTfirst chunk (pooled)101 (-4.7%)175 (+3.6%)372 (+84%) 🔻3550 (+770%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)115 (-20%)131 (-27%)168 (-42%)335 (-36%)96.5 (-32%)10
size sweep (100/s, 160B-12KB)127 (-9%)135 (-26%)172 (-32%)310 (-31%)134 (-14%)10
replay gateway-gpt-5.4-nano-2000t (1x)204 (+37%)139 (-4%)230 (+8%)675 (-3%)293 (+18%)3
replay eve-gpt-5.6-sol-2000t (1x)1837 (+1128%)140 (-5%)193 (±0%)3960 (+1082%)2212 (+683%)2
replay eve-gpt-5.6-sol-2000t (2x)372 (+120%)242 (+12%)468 (+23%)1195 (±0%)226 (-43%)3
ℹ️ Metric definitions & methodology
Streams: first-chunk RTT (the stream-open path, before any buffering/backpressure), CRTT percentiles, and worst delivery stall (CDV max). Cells are medians across iterations; per-run values in the artifacts. No 🔴/🟢 marks until targets attach.
The collapsed STSO distribution section above buckets every step gap, split inline (same warm process — pure framework overhead) vs queue-hop (fresh process — dispatch, reinit, replay). █ = main, ┃ = this run, ░ = fill.
The collapsed CRTT drill-down: per-variant RTT histograms (fixed log bins, · = empty) and mean RTT/positive-CDV profile lines over stream progress and chunk size. Histograms, avgs, and profiles merge exactly across runs; p50–p99 are percentile-of-percentiles. Per-index rows live in the artifacts.
Best/P75/P90/P99 deltas compare against the most recent benchmark run on main at the time of this run. 🔻 flags a delta worse than +15%, 💚 one better than −15%.
Metrics — TTFS: time to first step body (in-deployment start() → first step body) · Fan-out TTFS: fan-out time to first step (in-deployment start() → first of the parallel step bodies to complete) · Fan-out TTLS: fan-out time to last step (in-deployment start() → last of the parallel step bodies to complete, i.e. when the Promise.all resolves) · STSO: step-to-step overhead (gap between consecutive step bodies) · WO: workflow overhead (whole-run time outside step bodies, in-deployment anchored) · CRTT: chunk round-trip time (per-chunk write → read latency, one clock domain: deployment → stream backend → same deployment) · CDV: chunk delay variation / delivery jitter (inter-arrival gap minus inter-write gap per seq-adjacent pair; skew-free; the row is each run's MAX positive value, so one stall moves it)
Scenarios — step: one trivial no-op step, no stream; no hooks, so the run stays in turbo mode (in-process fast path) · stream: one streaming step; no hooks, so the run stays in turbo mode (in-process fast path) · hook + stream: registers a hook before one step, which exits turbo mode (dispatch path) · 1020 steps: 1020 trivial sequential steps; STSO is measured between consecutive steps in the given step ranges, and WO is the whole-run overhead outside step bodies · Promise.all(100 steps): 100 trivial no-op steps started together in a single Promise.all; Fan-out TTFS is the first of them to complete and Fan-out TTLS the last, both from the in-deployment clientStart, so their gap is the spread the runtime adds across the fan-out · paced control (100/s, 60B): the control: 300 tiny (~60B) deltas metronome-paced at 100/s — zero workload structure, so it reads the transport floor and flush cadence, and disambiguates transport-wide vs workload-specific when a replay row moves · size sweep (100/s, 160B-12KB): same pacing as the control with deltas padded in rotation across seven log-spaced sizes (~160B–12KB) — rotation decouples size from stream position, so it isolates whether chunk size causes latency · replay gateway-gpt-5.4-nano-2000t (1x): raw provider SSE cadence captured at the AI gateway boundary (gpt-5.4-nano, the most popular gateway model; per-token deltas p50 208B = the modal production chunk size), replayed exactly as measured — the typical customer's workload; its CDV is the typical customer's real delivery jitter · replay eve-gpt-5.6-sol-2000t (1x): a captured eve turn (gpt-5.6-sol, the most-used demanding eve model; ~2000 output tokens = production p50 turn length) replayed exactly as measured — eve's envelope protocol re-ships the cumulative message so sizes ramp 142B→13KB; the demanding outlier tenant's reality · replay eve-gpt-5.6-sol-2000t (2x): the same eve capture at 2x — the headroom/stress row; real fast-tier models emit the same chunk sizes at proportionally higher rate, so time compression is a faithful speed model · first chunk (pooled): every run's seq-0 RTT pooled across all stream scenarios — the first chunk precedes any workload differentiation, so pooling samples one shared stream-open path with exact percentiles
Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000teaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041
🔴 marks a percentile over its target (within target is left unmarked). Targets (p75/p90/p99, ms) — TTFS 200/300/600
All timestamps are deployment-side; runs are triggered in-deployment, so the CI runner and api.vercel.com sit outside every measured window. TTFS = start() → first step body (includes dispatch + any cold start); Fan-out TTFS/TTLS = first/last step completion of one Promise.all from the same anchor (the gap is the runtime’s fan-out spread); STSO/WO between step bodies; CRTT inside the workflow (excludes the api.vercel.com read path).
Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.
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Sim World
Simulated world deterministic testing for races. Traces
🟠 world-sim scenario book — 1 fail of 41 total
fence=per-spec
scenariooutcomeeventsvirtreplayviolations
✅ smoke-no-stepscompleted30msok0
✅ smoke-one-stepcompleted60msok0
✅ hook-at-step-startedcompleted120msok0
✅ hook-at-step-completedcompleted120msok0
✅ hook-at-hook-createdcompleted120msok0
✅ deadline-hook-winscompleted71.0hok0
✅ deadline-expirescompleted71.0hok0
✅ long-sleepcompleted1130.0dok0
✅ hook-never-arrivesstalled30msskipped0
✅ step-retries-twicecompleted102.0sok0
✅ parallel-stepscompleted90msok0
✅ hook-on-execution-statecompleted120msok0
✅ peek-hook-before-branchcompleted120msok0
✅ peek-hook-after-branchcompleted120msok0
✅ peek-hook-at-registrationcompleted120msok0
✅ race-hook-before-probecompleted120msok0
✅ race-hook-after-probecompleted120msok0
✅ race-duplicate-deliverycompleted130msok0
✅ attr-hook-before-stepcompleted110msok0
✅ attr-hook-after-stepcompleted110msok0
✅ attr-from-step-bodycompleted130msok0
✅ fork-hook-after-timeoutcompleted141.0mok0
✅ fork-hook-before-timeoutcompleted141.0mok0
✅ count-hook-after-timeoutcompleted171.0mok0
✅ count-hook-before-timeoutcompleted201.0mok0
✅ stale-read-step-count-forkcompleted201.0mok0
✅ stale-read-equal-step-countscompleted141.0mok0
✅ step-vs-step-forkcompleted120msok0
✅ step-vs-step-fork-fencedcompleted120msok0
✅ fence-catches-benign-directioncompleted125msok0
✅ in-flight-before-decisioncompleted171.0mok0
❌ in-flight-before-decision-countedcompleted171.0mok0
✅ in-flight-after-decisioncompleted192.0mok0
✅ stale-read-step-count-fork-fencedcompleted201.0mok0
✅ fork-hook-winscompleted131.0mok0
✅ fork-timeout-winscompleted131.0mok0
✅ unclaimed-payload-under-forkcompleted171.0mok0
✅ claimed-payload-under-forkcompleted171.0mok0
✅ writers-independent-step-bodiescompleted120msok0
✅ writers-scripted-tempocompleted120msok0
✅ cancel-mid-stepcancelled70msskipped0
Full trace: world-sim.txt
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marked this pull request as ready for review
August 21, 2026 22:48
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merged commit 5841558
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peter/windows-step-registration-cleanup

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August 25, 2026 19:07
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No backport to stable for 5841558 (AI decision).
This is CI/test hardening for a failure mode that does not exist on stable: the generated __step_registrations.js that strands a deleted step fixture is main-only (on stable, step_registration appears only in the SWC plugin's Rust, and packages/next generates no such file), and the dev.test.ts changes build on main-only harness pieces (generatedStepRegistrationPath config, restoreDirectories). The tests.yml hunk likewise rewrites a Get-DevServerStatus pre-e2e probe block that stable does not have at all. Nothing here keeps stable buildable, testable, or releasable.
To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:
584155897f75e712a1c2bc199d6d12027cd18dab

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, 'i');
if (__m === '*' || __re.test(location.href)) {
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[core] Fail dev HMR cleanup on a stranded step registration - #3682
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peter/windows-step-registration-cleanup
Aug 25, 2026
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[core] Fail dev HMR cleanup on a stranded step registration#3682
VaguelySerious merged 3 commits into
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peter/windows-step-registration-cleanup
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Problem
Three of the last 120 Tests runs had E2E Windows Tests (node) burn its full ~30-minute

window and get cancelled with every e2e test failing on
[world-local] Queue message failed (HTTP 500), where the handlerError is a Next.js
_error page rather than anything workflow-shaped:
jobflow-route 500sstranded-import errors
9622825337310,13520,346
9621451553010,21810,886
9620285500910,28020,557
The flow route never answered a single request successfully in any of them. The dev server

log says why:
⨯ app/.well-known/workflow/v1/flow/__step_registrations.js:33:1
Module not found: Can't resolve '../../../../../workflows/source-map-warning-fixture.ts'

dev.test.ts > "should not log source map warnings for workflow node_modules imports"

writes workflows/source-map-warning-fixture.ts, which declares a 'use step' function,

and its afterEach deletes it. The generated __step_registrations.js imports every

discovered step file by path, so that deletion only stops breaking the flow route once a

rediscovery regenerates the file. When the watcher drops the unlink — which is what happens

on Windows — the generated file keeps importing a path that no longer exists, the flow route

stops compiling, and every workflow dispatch for the rest of the job gets a 500 pointing at

a fixture from a test that already passed.
The HMR log confirms nothing recovers it: 164 → 165 → 166 → 165 → 165 workflows, then

three skips and no further rediscovery. afterEach's prewarm() only waits for
workflow dev hmr: ready, printed once at startup, so nothing ever waited for the

post-deletion rediscovery in the first place.
The generated workflow bundle inlines workflow sources instead of importing them, so only
step-declaring fixtures can strand it. That is why new-workflow.ts leaks harmlessly in

the same runs while the source-map fixture is fatal.
The existing fail-fast guard cannot see this
The Windows job already probes the dev server before the long e2e run, precisely to avoid

burning the job window on a wedged server. It probes GET /api/chat, which compiles

independently of the flow route, so it reported -> 405 and let the suite run in all three

jobs.
Changes
  1. packages/core/e2e/dev.test.ts — after deleting fixtures, cleanup waits for the
    
generated step registrations to stop importing them. If they still do when the budget
    
runs out, the fixture contents are written back so the shared dev server keeps serving
    
the rest of the suite, and the hook fails naming the stranded file. CI already skips the
    
e2e suite when dev.test.ts fails, so this turns a 30-minute burn with ~10k misleading
    
500s into an immediate, accurate failure. The convergence wait runs before the
    node_modules fixture-package removal so a restored fixture still resolves its import.
  2. .github/workflows/tests.yml — the pre-e2e probe now POSTs
    /.well-known/workflow/v1/flow?__health, the SDK's own health endpoint on the route
    
that actually breaks. It returns 200 on a healthy dev server and would have returned 500
    
in all three jobs above.
Validation
Run locally against workbench/nextjs-turbopack on macOS (all 9 dev tests, so including

the flow-route HMR fuzz cases that also delete step-declaring files):
  • Happy path: the convergence wait never trips on any of the tests that delete fixtures. A
    
deletion converges in ~2s, so the watcher path itself is sound and the Windows miss is the
    
discriminator.
  • should follow Next flow-route HMR rebuild rules for body-only changes fails on macOS
    
(expected 2 to be 1 on an exact HMR log count). It fails identically with unmodified
    origin/main's dev.test.ts against the same dev server, so it is pre-existing and
    
unrelated. That case is skipped on Windows.
  • Forced-failure path (convergence budget shortened so it always expires): the hook fails
    
with the stranded path named, the fixture is restored, and
    POST /.well-known/workflow/v1/flow?__health still answers 200.
  • POST /.well-known/workflow/v1/flow?__health returns 200 on a healthy dev server and 500
    
when a path reachable from __step_registrations.js does not resolve, while
    GET /api/chat keeps answering 405 — the asymmetry the second change fixes.
The underlying Windows watcher miss is worth chasing separately; this PR stops it from

costing a whole job and makes it name itself.
Note on a related hole, not changed here
The Linux e2e-local-dev lane runs pnpm vitest run packages/core/e2e/dev.test.ts; sleep 10

and then continues into the full e2e suite, so a dev.test.ts failure there is discarded.

That lane would swallow the new hook failure too. Tightening it would newly red the lane on

pre-existing dev.test.ts flakes (the flow-route HMR fuzz case already fails on macOS

against unmodified main, see below), so it seemed worth raising separately rather than

bundling in.
@VaguelySerious@claude
[core] Fail dev HMR cleanup on a stranded step registration
62fcd0f
`dev.test.ts` fixtures that declare a `'use step'` function are imported by
path from the generated `__step_registrations.js`, so deleting one only stops
breaking the flow route once a rediscovery regenerates that file. When the dev
server's watcher drops the unlink, the generated file keeps importing a path
that no longer exists: the flow route stops compiling and every later workflow
dispatch in the job gets a 500 that names a fixture from a test that already
passed. Three of the last 120 `Tests` runs lost the whole ~30-minute Windows
e2e window this way, each with ~10k flow-route 500s and no successful dispatch.
Cleanup now waits for the generated step registrations to drop every file it
deleted. If they still reference one when the budget expires, the fixture is
written back so the shared dev server keeps serving the rest of the suite, and
the hook fails naming the stranded path. The wait runs before the node_modules
fixture-package removal so a restored fixture still resolves its import.
The pre-e2e probe moves from `GET /api/chat` to
`POST /.well-known/workflow/v1/flow?__health`. /api/chat compiles independently
of the flow route, so it answered 405 in all three jobs while every dispatch
was getting a 500.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Aug 19, 2026•

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🦋 Changeset detected
Latest commit: d11c0dd
The changes in this PR will be included in the next version bump.
This PR includes changesets to release 16 packages
NameType
@workflow/corePatch
@workflow/buildersPatch
@workflow/cliPatch
@workflow/nextPatch
@workflow/nitroPatch
@workflow/vitestPatch
@workflow/web-sharedPatch
@workflow/webPatch
workflowPatch
@workflow/world-testingPatch
@workflow/astroPatch
@workflow/nestPatch
@workflow/rollupPatch
@workflow/sveltekitPatch
@workflow/vitePatch
@workflow/nuxtPatch
Not sure what this means? Click here to learn what changesets are.
Click here if you're a maintainer who wants to add another changeset to this PR
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ProjectDeploymentActionsUpdated (UTC)
example-nextjs-workflow-turbopackReadyReadyPreview, v0Aug 24, 2026 10:33pm
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🧪 E2E Test Results
❌ Some tests failed
❌ Failed E2E Tests
▲ Vercel Production (8 failed)
python-node (8 failed):
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9 | 🔍 observability
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K | 🔍 observability
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1 | 🔍 observability
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C | 🔍 observability
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C | 🔍 observability
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV | 🔍 observability
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG | 🔍 observability
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP | 🔍 observability
🌐 Cross-language Conformance (9 failed)
python (9 failed):
  • deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0TYP4EWXS4MHWKXFZN1JR0F
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP
⚠️ Flaky E2E Tests (passed on retry)
These tests failed at least once and passed on a retry. A recurring entry here is a real race worth investigating.
  • addTenWorkflow (fastify)
  • addTenWorkflow (hono)
  • addTenWorkflow (nuxt)
  • cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
  • cancelRun via CLI - cancelling a running workflow (nuxt)
  • hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (nextjs-webpack)
  • hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (nextjs-webpack)
  • sleepWinsRaceWorkflow (tanstack-start)
🛠 Infra Events (absorbed by the harness)
Platform anomalies the e2e harness detected and worked around (e.g. a run the queue never picked up, replaced by a fresh run). Clustered timestamps indicate a backend blip; a steady drip indicates a platform issue worth escalating.
32 infra events
  • cold-start-warmup · suite warmup (python) · at 22:32:26Z · abandoned wrun_41M0TYAYJT0GNGCGFT9CW8J31C · (+7 more)
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN9
  • run-pickup-stall · nullByteWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKF10GW0JY2HGZZ2K8BR
  • run-pickup-stall · sleepingWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN8
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKTR0GSK8P4JGC50Q9YT
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:32:43Z · abandoned wrun_41M0TYEKEQ0GVKJ0FPW7DV5X07
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:33:15Z · abandoned wrun_41M0TYFKB30GZV9RYEXPSVWC4S
  • run-pickup-stall · sleepingWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYP0GNT5G4RBTCFB13K
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF3N0GT1E7GFW1V9TJ21
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYS0GY7C05YYWCVAN24
  • run-pickup-stall · nullByteWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF250GVD8T6M4BGNC9MZ
  • cold-start-warmup · suite warmup (tanstack-start) · at 22:34:07Z · abandoned wrun_01M0TYGV52206SC5AEK09QTHDV
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:34:33Z · abandoned wrun_41M0TYGK1Q0GP2X8Z95ZQRRF08
  • cold-start-warmup · suite warmup (python) · at 22:35:18Z · abandoned wrun_01M0TYG6112GWK343TTH7VNV7D · (+7 more)
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36E
  • run-pickup-stall · sleepingWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5VB4BEN37GS66N59YK
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5Y18NPGYQK6XKMNBJY
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36D
  • run-pickup-stall · nullByteWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV60YRZTH9DG0JNDANBH
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSJYNGNK851MQP1JB09
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSGB77J7W5E13A3R263
  • run-pickup-stall · sleepingWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSM1WW7VT6JAS9B0VEX
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSQ61EMZQSZ849JNHA7
  • run-pickup-stall · nullByteWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSR4ER537QZBJ79SN2G
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:36:55Z · abandoned wrun_41M0TYK6V80GQ8NYJDE1PPJBXH
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:36:55Z · abandoned wrun_41M0TYKAY70GYG61T79VHX87WA
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGD6NDH7M075CNB00CER
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDAM3PHNF2JA81T8P7Z
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDH2ZVXYM64QF0HSDRM
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRQC396P9TA2NFEF1YW
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRY07WYKZTT81X3CSEA
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:38:33Z · abandoned wrun_01M0TYSB0M52SKJN6P09C9FJ4R
E2E Test Summary
Summary
PassedFailedSkippedTotal
❌ ▲ Vercel Production357087424320
✅ 💻 Local Development392205584480
✅ 📦 Local Production392205584480
✅ 🐘 Local Postgres392205584480
✅ 🪟 Windows32000320
❌ 🌐 Cross-language Conformance09132141
✅ vercel-http-transport8170143960
✅ vercel-multi-region270027
✅ vercel-ws-transport553087640
Total1705317277819848
Details by Category
❌ ▲ Vercel Production
AppPassedFailedSkipped
✅ astro-node132028
✅ astro-quickjs132028
✅ example-node132028
✅ example-quickjs132028
✅ express-node132028
✅ express-quickjs132028
✅ fastify-node132028
✅ fastify-quickjs132028
✅ hono-node132028
✅ hono-quickjs132028
✅ nest-node132028
✅ nest-quickjs132028
✅ nextjs-turbopack-node15703
✅ nextjs-turbopack-quickjs15703
✅ nextjs-webpack-node15703
✅ nextjs-webpack-quickjs15703
✅ nitro-node132028
✅ nitro-quickjs132028
✅ nuxt-node132028
✅ nuxt-quickjs132028
❌ python-node08152
✅ sveltekit-node15109
✅ sveltekit-quickjs15109
✅ tanstack-start-node132028
✅ tanstack-start-quickjs132028
✅ vite-node132028
✅ vite-quickjs132028
✅ 💻 Local Development
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 📦 Local Production
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🐘 Local Postgres
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🪟 Windows
AppPassedFailedSkipped
✅ nextjs-turbopack-node16000
✅ nextjs-turbopack-quickjs16000
❌ 🌐 Cross-language Conformance
AppPassedFailedSkipped
❌ python09132
✅ vercel-http-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ hono132028
✅ nextjs-turbopack15703
✅ nitro132028
✅ vite132028
✅ vercel-multi-region
AppPassedFailedSkipped
✅ nextjs-turbopack2700
✅ vercel-ws-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ nextjs-turbopack15703
✅ vite132028
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📊 Workflow Benchmarks
commit d11c0dd · Mon, 24 Aug 2026 22:55:03 GMT · run logs
Backend: vercel · app: nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep246 (-75%) 💚1346 🔴 (+22%) 🔻1384 🔴 (+20%) 🔻1484 🔴 (+18%) 🔻30
TTFSstream222 (-69%) 💚1328 🔴 (+21%) 🔻1400 🔴 (+26%) 🔻1432 🔴 (+11%)30
TTFShook + stream1264 (-8.0%)1646 🔴 (+12%)1722 🔴 (+14%)2321 🔴 (+45%) 🔻30
Fan-out TTFSPromise.all(100 steps)645 (-0.8%)1882 (+10%)2135 (+19%) 🔻2343 (+20%) 🔻10
Fan-out TTLSPromise.all(100 steps)1841 (-4.7%)3816 (+20%) 🔻5084 (+55%) 🔻5570 (-34%) 💚10
STSO1020 steps (inline)69 (-34%) 💚140 (-5.4%)164 (-2.4%)275 (+26%) 🔻1019
WO1020 steps140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)1
CRTTfirst chunk (pooled)107 (+22%) 🔻171 (+38%) 🔻260 (+35%) 🔻274 (-56%) 💚28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+25%)256 (+97%)513 (+142%)967 (+27%)279 (+95%)10
size sweep (100/s, 160B-12KB)150 (+33%)164 (+15%)275 (+47%)495 (-56%)195 (+42%)10
replay gateway-gpt-5.4-nano-2000t (1x)131 (+7%)532 (-18%)706 (-79%)911 (-81%)203 (-6%)3
replay eve-gpt-5.6-sol-2000t (1x)216 (+83%)168 (+25%)261 (+54%)1122 (+225%)761 (+191%)2
replay eve-gpt-5.6-sol-2000t (2x)150 (+22%)207 (+13%)274 (+4%)691 (+25%)268 (+18%)3
📈 STSO distribution vs main (inline / queue-hop histograms)
1020 steps (inline)
Cumulative STSO time: main 147417ms → this run 140462ms (Δ -6955ms, -5%)
 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████░┃ main 785 this 848 +63
150-200 ms ███┃██ main 216 this 143 -73
200-250 ms ┃ main 14 this 11 -3
250-300 ms ┃ main 4 this 9 +5
300-350 ms ┃ main 0 this 5 +5
350-400 ms ┃ main 0 this 1 +1
400-450 ms ┃ main 0 this 1 +1

📈 CRTT drill-down vs main (RTT distributions & profiles)
variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▃█▃▁··· 175.1 (+46%) 135 (+27%) 513 (+142%) 967 (+27%) 3000
sweep ······▃█▂▁··· 136.8 (+11%) 122 (+11%) 275 (+47%) 495 (-56%) 3000
gw 1x ·····▁▄█▃▂··· 203.3 (-39%) 119 (+18%) 706 (-79%) 911 (-81%) 5295
eve 1x ·····▁▃█▂▁▁·· 171.8 (+55%) 129 (+42%) 261 (+54%) 1122 (+225%) 5186
eve 2x ·····▁▂█▃▁··· 167.7 (+20%) 149 (+16%) 274 (+4%) 691 (+25%) 7779

RTT over stream progress (avg per tenth of stream, bars scaled min→max):
control ▅█▄▆▃▄▁▆▅█ 145–199ms
sweep █▆▂▁▂▅▃▁▃▂ 116–178ms
gw 1x ██▄▄▅▁▂▄▇▅ 122–275ms
eve 1x ▂▂▃▂▁▁▄█▁▁ 121–326ms
eve 2x ▃▁▁▁▁▂▅██▂ 142–224ms

RTT by chunk size (avg per log size bin, ~160B → ~12KB serialized, bars scaled min→max):
sweep ▁▅█▅▅▂▃ 136–138ms

Delivery jitter over stream progress (avg positive CDV per tenth of stream, bars scaled min→max):
control ▄▁▁▆▆▃▆▄█▅ 34–56ms
sweep ▁▃▃▃▆▄▆▄█▂ 44–59ms
gw 1x █▄▂▂▃▁▄▃▆▃ 38–71ms
eve 1x ▅▆▆▅▃▁█▅▃▃ 24–39ms
eve 2x █▇▁▃▆▅█▃▄▆ 22–36ms

📜 Previous results (2)
47501c6
Fri, 21 Aug 2026 23:12:41 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1314 (+22%) 🔻1396 🔴 (+21%) 🔻1428 🔴 (+14%)1481 🔴 (+3.6%)30
TTFSstream270 (-75%) 💚1352 🔴 (+12%)1378 🔴 (+7.1%)1389 🔴 (-3.9%)30
TTFShook + stream1534 (+45%) 🔻1659 🔴 (+14%)1766 🔴 (+17%) 🔻2433 🔴 (+57%) 🔻30
Fan-out TTFSPromise.all(100 steps)568 (-4.1%)2033 (+28%) 🔻2052 (+24%) 🔻2111 (+27%) 🔻10
Fan-out TTLSPromise.all(100 steps)1699 (+5.1%)3860 (+28%) 🔻4036 (+12%)4573 (+16%) 🔻10
STSO1020 steps (inline)114 (-24%) 💚168 (-24%) 💚189 (-27%) 💚344 (-36%) 💚1019
WO1020 steps169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚1
CRTTfirst chunk (pooled)99 (+4.2%)152 (+2.7%)189 (+8.6%)376 (+62%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+9%)143 (-23%)186 (-27%)402 (+6%)110 (-35%)10
size sweep (100/s, 160B-12KB)125 (+1%)151 (-18%)195 (-42%)279 (-46%)99.5 (-25%)10
replay gateway-gpt-5.4-nano-2000t (1x)152 (+26%)189 (-74%)414 (-87%)757 (-84%)466 (-86%)3
replay eve-gpt-5.6-sol-2000t (1x)159 (+31%)148 (-8%)186 (-10%)287 (-20%)296 (-2%)2
replay eve-gpt-5.6-sol-2000t (2x)135 (-13%)200 (-38%)268 (-73%)380 (-83%)246 (-38%)3
62fcd0f
Wed, 19 Aug 2026 23:10:40 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1287 (+24%) 🔻1401 🔴 (+19%) 🔻1442 🔴 (+17%) 🔻1732 🔴 (+4.1%)30
TTFSstream1260 (+25%) 🔻1388 🔴 (+25%) 🔻1428 🔴 (+25%) 🔻1742 🔴 (+49%) 🔻30
TTFShook + stream538 (-58%) 💚1644 🔴 (+15%)1690 🔴 (+15%)1986 🔴 (+26%) 🔻30
Fan-out TTFSPromise.all(100 steps)527 (-7.9%)829 (-16%) 💚986 (-45%) 💚2498 (+38%) 🔻10
Fan-out TTLSPromise.all(100 steps)4804 (+1.2%)8742 (+6.0%)9471 (-13%)10733 (-19%) 💚10
STSO1020 steps (inline)117 (-5.6%)159 (-35%) 💚185 (-37%) 💚303 (-40%) 💚1019
WO1020 steps158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚1
CRTTfirst chunk (pooled)101 (-4.7%)175 (+3.6%)372 (+84%) 🔻3550 (+770%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)115 (-20%)131 (-27%)168 (-42%)335 (-36%)96.5 (-32%)10
size sweep (100/s, 160B-12KB)127 (-9%)135 (-26%)172 (-32%)310 (-31%)134 (-14%)10
replay gateway-gpt-5.4-nano-2000t (1x)204 (+37%)139 (-4%)230 (+8%)675 (-3%)293 (+18%)3
replay eve-gpt-5.6-sol-2000t (1x)1837 (+1128%)140 (-5%)193 (±0%)3960 (+1082%)2212 (+683%)2
replay eve-gpt-5.6-sol-2000t (2x)372 (+120%)242 (+12%)468 (+23%)1195 (±0%)226 (-43%)3
ℹ️ Metric definitions & methodology
Streams: first-chunk RTT (the stream-open path, before any buffering/backpressure), CRTT percentiles, and worst delivery stall (CDV max). Cells are medians across iterations; per-run values in the artifacts. No 🔴/🟢 marks until targets attach.
The collapsed STSO distribution section above buckets every step gap, split inline (same warm process — pure framework overhead) vs queue-hop (fresh process — dispatch, reinit, replay). █ = main, ┃ = this run, ░ = fill.
The collapsed CRTT drill-down: per-variant RTT histograms (fixed log bins, · = empty) and mean RTT/positive-CDV profile lines over stream progress and chunk size. Histograms, avgs, and profiles merge exactly across runs; p50–p99 are percentile-of-percentiles. Per-index rows live in the artifacts.
Best/P75/P90/P99 deltas compare against the most recent benchmark run on main at the time of this run. 🔻 flags a delta worse than +15%, 💚 one better than −15%.
Metrics — TTFS: time to first step body (in-deployment start() → first step body) · Fan-out TTFS: fan-out time to first step (in-deployment start() → first of the parallel step bodies to complete) · Fan-out TTLS: fan-out time to last step (in-deployment start() → last of the parallel step bodies to complete, i.e. when the Promise.all resolves) · STSO: step-to-step overhead (gap between consecutive step bodies) · WO: workflow overhead (whole-run time outside step bodies, in-deployment anchored) · CRTT: chunk round-trip time (per-chunk write → read latency, one clock domain: deployment → stream backend → same deployment) · CDV: chunk delay variation / delivery jitter (inter-arrival gap minus inter-write gap per seq-adjacent pair; skew-free; the row is each run's MAX positive value, so one stall moves it)
Scenarios — step: one trivial no-op step, no stream; no hooks, so the run stays in turbo mode (in-process fast path) · stream: one streaming step; no hooks, so the run stays in turbo mode (in-process fast path) · hook + stream: registers a hook before one step, which exits turbo mode (dispatch path) · 1020 steps: 1020 trivial sequential steps; STSO is measured between consecutive steps in the given step ranges, and WO is the whole-run overhead outside step bodies · Promise.all(100 steps): 100 trivial no-op steps started together in a single Promise.all; Fan-out TTFS is the first of them to complete and Fan-out TTLS the last, both from the in-deployment clientStart, so their gap is the spread the runtime adds across the fan-out · paced control (100/s, 60B): the control: 300 tiny (~60B) deltas metronome-paced at 100/s — zero workload structure, so it reads the transport floor and flush cadence, and disambiguates transport-wide vs workload-specific when a replay row moves · size sweep (100/s, 160B-12KB): same pacing as the control with deltas padded in rotation across seven log-spaced sizes (~160B–12KB) — rotation decouples size from stream position, so it isolates whether chunk size causes latency · replay gateway-gpt-5.4-nano-2000t (1x): raw provider SSE cadence captured at the AI gateway boundary (gpt-5.4-nano, the most popular gateway model; per-token deltas p50 208B = the modal production chunk size), replayed exactly as measured — the typical customer's workload; its CDV is the typical customer's real delivery jitter · replay eve-gpt-5.6-sol-2000t (1x): a captured eve turn (gpt-5.6-sol, the most-used demanding eve model; ~2000 output tokens = production p50 turn length) replayed exactly as measured — eve's envelope protocol re-ships the cumulative message so sizes ramp 142B→13KB; the demanding outlier tenant's reality · replay eve-gpt-5.6-sol-2000t (2x): the same eve capture at 2x — the headroom/stress row; real fast-tier models emit the same chunk sizes at proportionally higher rate, so time compression is a faithful speed model · first chunk (pooled): every run's seq-0 RTT pooled across all stream scenarios — the first chunk precedes any workload differentiation, so pooling samples one shared stream-open path with exact percentiles
Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000teaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041
🔴 marks a percentile over its target (within target is left unmarked). Targets (p75/p90/p99, ms) — TTFS 200/300/600
All timestamps are deployment-side; runs are triggered in-deployment, so the CI runner and api.vercel.com sit outside every measured window. TTFS = start() → first step body (includes dispatch + any cold start); Fan-out TTFS/TTLS = first/last step completion of one Promise.all from the same anchor (the gap is the runtime’s fan-out spread); STSO/WO between step bodies; CRTT inside the workflow (excludes the api.vercel.com read path).
Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.
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Sim World
Simulated world deterministic testing for races. Traces
🟠 world-sim scenario book — 1 fail of 41 total
fence=per-spec
scenariooutcomeeventsvirtreplayviolations
✅ smoke-no-stepscompleted30msok0
✅ smoke-one-stepcompleted60msok0
✅ hook-at-step-startedcompleted120msok0
✅ hook-at-step-completedcompleted120msok0
✅ hook-at-hook-createdcompleted120msok0
✅ deadline-hook-winscompleted71.0hok0
✅ deadline-expirescompleted71.0hok0
✅ long-sleepcompleted1130.0dok0
✅ hook-never-arrivesstalled30msskipped0
✅ step-retries-twicecompleted102.0sok0
✅ parallel-stepscompleted90msok0
✅ hook-on-execution-statecompleted120msok0
✅ peek-hook-before-branchcompleted120msok0
✅ peek-hook-after-branchcompleted120msok0
✅ peek-hook-at-registrationcompleted120msok0
✅ race-hook-before-probecompleted120msok0
✅ race-hook-after-probecompleted120msok0
✅ race-duplicate-deliverycompleted130msok0
✅ attr-hook-before-stepcompleted110msok0
✅ attr-hook-after-stepcompleted110msok0
✅ attr-from-step-bodycompleted130msok0
✅ fork-hook-after-timeoutcompleted141.0mok0
✅ fork-hook-before-timeoutcompleted141.0mok0
✅ count-hook-after-timeoutcompleted171.0mok0
✅ count-hook-before-timeoutcompleted201.0mok0
✅ stale-read-step-count-forkcompleted201.0mok0
✅ stale-read-equal-step-countscompleted141.0mok0
✅ step-vs-step-forkcompleted120msok0
✅ step-vs-step-fork-fencedcompleted120msok0
✅ fence-catches-benign-directioncompleted125msok0
✅ in-flight-before-decisioncompleted171.0mok0
❌ in-flight-before-decision-countedcompleted171.0mok0
✅ in-flight-after-decisioncompleted192.0mok0
✅ stale-read-step-count-fork-fencedcompleted201.0mok0
✅ fork-hook-winscompleted131.0mok0
✅ fork-timeout-winscompleted131.0mok0
✅ unclaimed-payload-under-forkcompleted171.0mok0
✅ claimed-payload-under-forkcompleted171.0mok0
✅ writers-independent-step-bodiescompleted120msok0
✅ writers-scripted-tempocompleted120msok0
✅ cancel-mid-stepcancelled70msskipped0
Full trace: world-sim.txt
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deleted the

peter/windows-step-registration-cleanup

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August 25, 2026 19:07
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No backport to stable for 5841558 (AI decision).
This is CI/test hardening for a failure mode that does not exist on stable: the generated __step_registrations.js that strands a deleted step fixture is main-only (on stable, step_registration appears only in the SWC plugin's Rust, and packages/next generates no such file), and the dev.test.ts changes build on main-only harness pieces (generatedStepRegistrationPath config, restoreDirectories). The tests.yml hunk likewise rewrites a Get-DevServerStatus pre-e2e probe block that stable does not have at all. Nothing here keeps stable buildable, testable, or releasable.
To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:
584155897f75e712a1c2bc199d6d12027cd18dab

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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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[core] Fail dev HMR cleanup on a stranded step registration - #3682
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[core] Fail dev HMR cleanup on a stranded step registration#3682
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peter/windows-step-registration-cleanup
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Problem
Three of the last 120 Tests runs had E2E Windows Tests (node) burn its full ~30-minute

window and get cancelled with every e2e test failing on
[world-local] Queue message failed (HTTP 500), where the handlerError is a Next.js
_error page rather than anything workflow-shaped:
jobflow-route 500sstranded-import errors
9622825337310,13520,346
9621451553010,21810,886
9620285500910,28020,557
The flow route never answered a single request successfully in any of them. The dev server

log says why:
⨯ app/.well-known/workflow/v1/flow/__step_registrations.js:33:1
Module not found: Can't resolve '../../../../../workflows/source-map-warning-fixture.ts'

dev.test.ts > "should not log source map warnings for workflow node_modules imports"

writes workflows/source-map-warning-fixture.ts, which declares a 'use step' function,

and its afterEach deletes it. The generated __step_registrations.js imports every

discovered step file by path, so that deletion only stops breaking the flow route once a

rediscovery regenerates the file. When the watcher drops the unlink — which is what happens

on Windows — the generated file keeps importing a path that no longer exists, the flow route

stops compiling, and every workflow dispatch for the rest of the job gets a 500 pointing at

a fixture from a test that already passed.
The HMR log confirms nothing recovers it: 164 → 165 → 166 → 165 → 165 workflows, then

three skips and no further rediscovery. afterEach's prewarm() only waits for
workflow dev hmr: ready, printed once at startup, so nothing ever waited for the

post-deletion rediscovery in the first place.
The generated workflow bundle inlines workflow sources instead of importing them, so only
step-declaring fixtures can strand it. That is why new-workflow.ts leaks harmlessly in

the same runs while the source-map fixture is fatal.
The existing fail-fast guard cannot see this
The Windows job already probes the dev server before the long e2e run, precisely to avoid

burning the job window on a wedged server. It probes GET /api/chat, which compiles

independently of the flow route, so it reported -> 405 and let the suite run in all three

jobs.
Changes
  1. packages/core/e2e/dev.test.ts — after deleting fixtures, cleanup waits for the
    
generated step registrations to stop importing them. If they still do when the budget
    
runs out, the fixture contents are written back so the shared dev server keeps serving
    
the rest of the suite, and the hook fails naming the stranded file. CI already skips the
    
e2e suite when dev.test.ts fails, so this turns a 30-minute burn with ~10k misleading
    
500s into an immediate, accurate failure. The convergence wait runs before the
    node_modules fixture-package removal so a restored fixture still resolves its import.
  2. .github/workflows/tests.yml — the pre-e2e probe now POSTs
    /.well-known/workflow/v1/flow?__health, the SDK's own health endpoint on the route
    
that actually breaks. It returns 200 on a healthy dev server and would have returned 500
    
in all three jobs above.
Validation
Run locally against workbench/nextjs-turbopack on macOS (all 9 dev tests, so including

the flow-route HMR fuzz cases that also delete step-declaring files):
  • Happy path: the convergence wait never trips on any of the tests that delete fixtures. A
    
deletion converges in ~2s, so the watcher path itself is sound and the Windows miss is the
    
discriminator.
  • should follow Next flow-route HMR rebuild rules for body-only changes fails on macOS
    
(expected 2 to be 1 on an exact HMR log count). It fails identically with unmodified
    origin/main's dev.test.ts against the same dev server, so it is pre-existing and
    
unrelated. That case is skipped on Windows.
  • Forced-failure path (convergence budget shortened so it always expires): the hook fails
    
with the stranded path named, the fixture is restored, and
    POST /.well-known/workflow/v1/flow?__health still answers 200.
  • POST /.well-known/workflow/v1/flow?__health returns 200 on a healthy dev server and 500
    
when a path reachable from __step_registrations.js does not resolve, while
    GET /api/chat keeps answering 405 — the asymmetry the second change fixes.
The underlying Windows watcher miss is worth chasing separately; this PR stops it from

costing a whole job and makes it name itself.
Note on a related hole, not changed here
The Linux e2e-local-dev lane runs pnpm vitest run packages/core/e2e/dev.test.ts; sleep 10

and then continues into the full e2e suite, so a dev.test.ts failure there is discarded.

That lane would swallow the new hook failure too. Tightening it would newly red the lane on

pre-existing dev.test.ts flakes (the flow-route HMR fuzz case already fails on macOS

against unmodified main, see below), so it seemed worth raising separately rather than

bundling in.
@VaguelySerious@claude
[core] Fail dev HMR cleanup on a stranded step registration
62fcd0f
`dev.test.ts` fixtures that declare a `'use step'` function are imported by
path from the generated `__step_registrations.js`, so deleting one only stops
breaking the flow route once a rediscovery regenerates that file. When the dev
server's watcher drops the unlink, the generated file keeps importing a path
that no longer exists: the flow route stops compiling and every later workflow
dispatch in the job gets a 500 that names a fixture from a test that already
passed. Three of the last 120 `Tests` runs lost the whole ~30-minute Windows
e2e window this way, each with ~10k flow-route 500s and no successful dispatch.
Cleanup now waits for the generated step registrations to drop every file it
deleted. If they still reference one when the budget expires, the fixture is
written back so the shared dev server keeps serving the rest of the suite, and
the hook fails naming the stranded path. The wait runs before the node_modules
fixture-package removal so a restored fixture still resolves its import.
The pre-e2e probe moves from `GET /api/chat` to
`POST /.well-known/workflow/v1/flow?__health`. /api/chat compiles independently
of the flow route, so it answered 405 in all three jobs while every dispatch
was getting a 500.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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🦋 Changeset detected
Latest commit: d11c0dd
The changes in this PR will be included in the next version bump.
This PR includes changesets to release 16 packages
NameType
@workflow/corePatch
@workflow/buildersPatch
@workflow/cliPatch
@workflow/nextPatch
@workflow/nitroPatch
@workflow/vitestPatch
@workflow/web-sharedPatch
@workflow/webPatch
workflowPatch
@workflow/world-testingPatch
@workflow/astroPatch
@workflow/nestPatch
@workflow/rollupPatch
@workflow/sveltekitPatch
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example-nextjs-workflow-turbopackReadyReadyPreview, v0Aug 24, 2026 10:33pm
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example-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
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workflow-webReadyReadyPreview, v0Aug 24, 2026 10:33pm
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🧪 E2E Test Results
❌ Some tests failed
❌ Failed E2E Tests
▲ Vercel Production (8 failed)
python-node (8 failed):
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9 | 🔍 observability
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K | 🔍 observability
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1 | 🔍 observability
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C | 🔍 observability
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C | 🔍 observability
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV | 🔍 observability
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG | 🔍 observability
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP | 🔍 observability
🌐 Cross-language Conformance (9 failed)
python (9 failed):
  • deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0TYP4EWXS4MHWKXFZN1JR0F
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP
⚠️ Flaky E2E Tests (passed on retry)
These tests failed at least once and passed on a retry. A recurring entry here is a real race worth investigating.
  • addTenWorkflow (fastify)
  • addTenWorkflow (hono)
  • addTenWorkflow (nuxt)
  • cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
  • cancelRun via CLI - cancelling a running workflow (nuxt)
  • hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (nextjs-webpack)
  • hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (nextjs-webpack)
  • sleepWinsRaceWorkflow (tanstack-start)
🛠 Infra Events (absorbed by the harness)
Platform anomalies the e2e harness detected and worked around (e.g. a run the queue never picked up, replaced by a fresh run). Clustered timestamps indicate a backend blip; a steady drip indicates a platform issue worth escalating.
32 infra events
  • cold-start-warmup · suite warmup (python) · at 22:32:26Z · abandoned wrun_41M0TYAYJT0GNGCGFT9CW8J31C · (+7 more)
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN9
  • run-pickup-stall · nullByteWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKF10GW0JY2HGZZ2K8BR
  • run-pickup-stall · sleepingWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN8
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKTR0GSK8P4JGC50Q9YT
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:32:43Z · abandoned wrun_41M0TYEKEQ0GVKJ0FPW7DV5X07
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:33:15Z · abandoned wrun_41M0TYFKB30GZV9RYEXPSVWC4S
  • run-pickup-stall · sleepingWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYP0GNT5G4RBTCFB13K
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF3N0GT1E7GFW1V9TJ21
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYS0GY7C05YYWCVAN24
  • run-pickup-stall · nullByteWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF250GVD8T6M4BGNC9MZ
  • cold-start-warmup · suite warmup (tanstack-start) · at 22:34:07Z · abandoned wrun_01M0TYGV52206SC5AEK09QTHDV
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:34:33Z · abandoned wrun_41M0TYGK1Q0GP2X8Z95ZQRRF08
  • cold-start-warmup · suite warmup (python) · at 22:35:18Z · abandoned wrun_01M0TYG6112GWK343TTH7VNV7D · (+7 more)
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36E
  • run-pickup-stall · sleepingWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5VB4BEN37GS66N59YK
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5Y18NPGYQK6XKMNBJY
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36D
  • run-pickup-stall · nullByteWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV60YRZTH9DG0JNDANBH
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSJYNGNK851MQP1JB09
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSGB77J7W5E13A3R263
  • run-pickup-stall · sleepingWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSM1WW7VT6JAS9B0VEX
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSQ61EMZQSZ849JNHA7
  • run-pickup-stall · nullByteWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSR4ER537QZBJ79SN2G
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:36:55Z · abandoned wrun_41M0TYK6V80GQ8NYJDE1PPJBXH
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:36:55Z · abandoned wrun_41M0TYKAY70GYG61T79VHX87WA
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGD6NDH7M075CNB00CER
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDAM3PHNF2JA81T8P7Z
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDH2ZVXYM64QF0HSDRM
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRQC396P9TA2NFEF1YW
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRY07WYKZTT81X3CSEA
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:38:33Z · abandoned wrun_01M0TYSB0M52SKJN6P09C9FJ4R
E2E Test Summary
Summary
PassedFailedSkippedTotal
❌ ▲ Vercel Production357087424320
✅ 💻 Local Development392205584480
✅ 📦 Local Production392205584480
✅ 🐘 Local Postgres392205584480
✅ 🪟 Windows32000320
❌ 🌐 Cross-language Conformance09132141
✅ vercel-http-transport8170143960
✅ vercel-multi-region270027
✅ vercel-ws-transport553087640
Total1705317277819848
Details by Category
❌ ▲ Vercel Production
AppPassedFailedSkipped
✅ astro-node132028
✅ astro-quickjs132028
✅ example-node132028
✅ example-quickjs132028
✅ express-node132028
✅ express-quickjs132028
✅ fastify-node132028
✅ fastify-quickjs132028
✅ hono-node132028
✅ hono-quickjs132028
✅ nest-node132028
✅ nest-quickjs132028
✅ nextjs-turbopack-node15703
✅ nextjs-turbopack-quickjs15703
✅ nextjs-webpack-node15703
✅ nextjs-webpack-quickjs15703
✅ nitro-node132028
✅ nitro-quickjs132028
✅ nuxt-node132028
✅ nuxt-quickjs132028
❌ python-node08152
✅ sveltekit-node15109
✅ sveltekit-quickjs15109
✅ tanstack-start-node132028
✅ tanstack-start-quickjs132028
✅ vite-node132028
✅ vite-quickjs132028
✅ 💻 Local Development
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 📦 Local Production
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🐘 Local Postgres
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🪟 Windows
AppPassedFailedSkipped
✅ nextjs-turbopack-node16000
✅ nextjs-turbopack-quickjs16000
❌ 🌐 Cross-language Conformance
AppPassedFailedSkipped
❌ python09132
✅ vercel-http-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ hono132028
✅ nextjs-turbopack15703
✅ nitro132028
✅ vite132028
✅ vercel-multi-region
AppPassedFailedSkipped
✅ nextjs-turbopack2700
✅ vercel-ws-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ nextjs-turbopack15703
✅ vite132028
📋 View full workflow run
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📊 Workflow Benchmarks
commit d11c0dd · Mon, 24 Aug 2026 22:55:03 GMT · run logs
Backend: vercel · app: nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep246 (-75%) 💚1346 🔴 (+22%) 🔻1384 🔴 (+20%) 🔻1484 🔴 (+18%) 🔻30
TTFSstream222 (-69%) 💚1328 🔴 (+21%) 🔻1400 🔴 (+26%) 🔻1432 🔴 (+11%)30
TTFShook + stream1264 (-8.0%)1646 🔴 (+12%)1722 🔴 (+14%)2321 🔴 (+45%) 🔻30
Fan-out TTFSPromise.all(100 steps)645 (-0.8%)1882 (+10%)2135 (+19%) 🔻2343 (+20%) 🔻10
Fan-out TTLSPromise.all(100 steps)1841 (-4.7%)3816 (+20%) 🔻5084 (+55%) 🔻5570 (-34%) 💚10
STSO1020 steps (inline)69 (-34%) 💚140 (-5.4%)164 (-2.4%)275 (+26%) 🔻1019
WO1020 steps140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)1
CRTTfirst chunk (pooled)107 (+22%) 🔻171 (+38%) 🔻260 (+35%) 🔻274 (-56%) 💚28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+25%)256 (+97%)513 (+142%)967 (+27%)279 (+95%)10
size sweep (100/s, 160B-12KB)150 (+33%)164 (+15%)275 (+47%)495 (-56%)195 (+42%)10
replay gateway-gpt-5.4-nano-2000t (1x)131 (+7%)532 (-18%)706 (-79%)911 (-81%)203 (-6%)3
replay eve-gpt-5.6-sol-2000t (1x)216 (+83%)168 (+25%)261 (+54%)1122 (+225%)761 (+191%)2
replay eve-gpt-5.6-sol-2000t (2x)150 (+22%)207 (+13%)274 (+4%)691 (+25%)268 (+18%)3
📈 STSO distribution vs main (inline / queue-hop histograms)
1020 steps (inline)
Cumulative STSO time: main 147417ms → this run 140462ms (Δ -6955ms, -5%)
 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████░┃ main 785 this 848 +63
150-200 ms ███┃██ main 216 this 143 -73
200-250 ms ┃ main 14 this 11 -3
250-300 ms ┃ main 4 this 9 +5
300-350 ms ┃ main 0 this 5 +5
350-400 ms ┃ main 0 this 1 +1
400-450 ms ┃ main 0 this 1 +1

📈 CRTT drill-down vs main (RTT distributions & profiles)
variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▃█▃▁··· 175.1 (+46%) 135 (+27%) 513 (+142%) 967 (+27%) 3000
sweep ······▃█▂▁··· 136.8 (+11%) 122 (+11%) 275 (+47%) 495 (-56%) 3000
gw 1x ·····▁▄█▃▂··· 203.3 (-39%) 119 (+18%) 706 (-79%) 911 (-81%) 5295
eve 1x ·····▁▃█▂▁▁·· 171.8 (+55%) 129 (+42%) 261 (+54%) 1122 (+225%) 5186
eve 2x ·····▁▂█▃▁··· 167.7 (+20%) 149 (+16%) 274 (+4%) 691 (+25%) 7779

RTT over stream progress (avg per tenth of stream, bars scaled min→max):
control ▅█▄▆▃▄▁▆▅█ 145–199ms
sweep █▆▂▁▂▅▃▁▃▂ 116–178ms
gw 1x ██▄▄▅▁▂▄▇▅ 122–275ms
eve 1x ▂▂▃▂▁▁▄█▁▁ 121–326ms
eve 2x ▃▁▁▁▁▂▅██▂ 142–224ms

RTT by chunk size (avg per log size bin, ~160B → ~12KB serialized, bars scaled min→max):
sweep ▁▅█▅▅▂▃ 136–138ms

Delivery jitter over stream progress (avg positive CDV per tenth of stream, bars scaled min→max):
control ▄▁▁▆▆▃▆▄█▅ 34–56ms
sweep ▁▃▃▃▆▄▆▄█▂ 44–59ms
gw 1x █▄▂▂▃▁▄▃▆▃ 38–71ms
eve 1x ▅▆▆▅▃▁█▅▃▃ 24–39ms
eve 2x █▇▁▃▆▅█▃▄▆ 22–36ms

📜 Previous results (2)
47501c6
Fri, 21 Aug 2026 23:12:41 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1314 (+22%) 🔻1396 🔴 (+21%) 🔻1428 🔴 (+14%)1481 🔴 (+3.6%)30
TTFSstream270 (-75%) 💚1352 🔴 (+12%)1378 🔴 (+7.1%)1389 🔴 (-3.9%)30
TTFShook + stream1534 (+45%) 🔻1659 🔴 (+14%)1766 🔴 (+17%) 🔻2433 🔴 (+57%) 🔻30
Fan-out TTFSPromise.all(100 steps)568 (-4.1%)2033 (+28%) 🔻2052 (+24%) 🔻2111 (+27%) 🔻10
Fan-out TTLSPromise.all(100 steps)1699 (+5.1%)3860 (+28%) 🔻4036 (+12%)4573 (+16%) 🔻10
STSO1020 steps (inline)114 (-24%) 💚168 (-24%) 💚189 (-27%) 💚344 (-36%) 💚1019
WO1020 steps169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚1
CRTTfirst chunk (pooled)99 (+4.2%)152 (+2.7%)189 (+8.6%)376 (+62%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+9%)143 (-23%)186 (-27%)402 (+6%)110 (-35%)10
size sweep (100/s, 160B-12KB)125 (+1%)151 (-18%)195 (-42%)279 (-46%)99.5 (-25%)10
replay gateway-gpt-5.4-nano-2000t (1x)152 (+26%)189 (-74%)414 (-87%)757 (-84%)466 (-86%)3
replay eve-gpt-5.6-sol-2000t (1x)159 (+31%)148 (-8%)186 (-10%)287 (-20%)296 (-2%)2
replay eve-gpt-5.6-sol-2000t (2x)135 (-13%)200 (-38%)268 (-73%)380 (-83%)246 (-38%)3
62fcd0f
Wed, 19 Aug 2026 23:10:40 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1287 (+24%) 🔻1401 🔴 (+19%) 🔻1442 🔴 (+17%) 🔻1732 🔴 (+4.1%)30
TTFSstream1260 (+25%) 🔻1388 🔴 (+25%) 🔻1428 🔴 (+25%) 🔻1742 🔴 (+49%) 🔻30
TTFShook + stream538 (-58%) 💚1644 🔴 (+15%)1690 🔴 (+15%)1986 🔴 (+26%) 🔻30
Fan-out TTFSPromise.all(100 steps)527 (-7.9%)829 (-16%) 💚986 (-45%) 💚2498 (+38%) 🔻10
Fan-out TTLSPromise.all(100 steps)4804 (+1.2%)8742 (+6.0%)9471 (-13%)10733 (-19%) 💚10
STSO1020 steps (inline)117 (-5.6%)159 (-35%) 💚185 (-37%) 💚303 (-40%) 💚1019
WO1020 steps158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚1
CRTTfirst chunk (pooled)101 (-4.7%)175 (+3.6%)372 (+84%) 🔻3550 (+770%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)115 (-20%)131 (-27%)168 (-42%)335 (-36%)96.5 (-32%)10
size sweep (100/s, 160B-12KB)127 (-9%)135 (-26%)172 (-32%)310 (-31%)134 (-14%)10
replay gateway-gpt-5.4-nano-2000t (1x)204 (+37%)139 (-4%)230 (+8%)675 (-3%)293 (+18%)3
replay eve-gpt-5.6-sol-2000t (1x)1837 (+1128%)140 (-5%)193 (±0%)3960 (+1082%)2212 (+683%)2
replay eve-gpt-5.6-sol-2000t (2x)372 (+120%)242 (+12%)468 (+23%)1195 (±0%)226 (-43%)3
ℹ️ Metric definitions & methodology
Streams: first-chunk RTT (the stream-open path, before any buffering/backpressure), CRTT percentiles, and worst delivery stall (CDV max). Cells are medians across iterations; per-run values in the artifacts. No 🔴/🟢 marks until targets attach.
The collapsed STSO distribution section above buckets every step gap, split inline (same warm process — pure framework overhead) vs queue-hop (fresh process — dispatch, reinit, replay). █ = main, ┃ = this run, ░ = fill.
The collapsed CRTT drill-down: per-variant RTT histograms (fixed log bins, · = empty) and mean RTT/positive-CDV profile lines over stream progress and chunk size. Histograms, avgs, and profiles merge exactly across runs; p50–p99 are percentile-of-percentiles. Per-index rows live in the artifacts.
Best/P75/P90/P99 deltas compare against the most recent benchmark run on main at the time of this run. 🔻 flags a delta worse than +15%, 💚 one better than −15%.
Metrics — TTFS: time to first step body (in-deployment start() → first step body) · Fan-out TTFS: fan-out time to first step (in-deployment start() → first of the parallel step bodies to complete) · Fan-out TTLS: fan-out time to last step (in-deployment start() → last of the parallel step bodies to complete, i.e. when the Promise.all resolves) · STSO: step-to-step overhead (gap between consecutive step bodies) · WO: workflow overhead (whole-run time outside step bodies, in-deployment anchored) · CRTT: chunk round-trip time (per-chunk write → read latency, one clock domain: deployment → stream backend → same deployment) · CDV: chunk delay variation / delivery jitter (inter-arrival gap minus inter-write gap per seq-adjacent pair; skew-free; the row is each run's MAX positive value, so one stall moves it)
Scenarios — step: one trivial no-op step, no stream; no hooks, so the run stays in turbo mode (in-process fast path) · stream: one streaming step; no hooks, so the run stays in turbo mode (in-process fast path) · hook + stream: registers a hook before one step, which exits turbo mode (dispatch path) · 1020 steps: 1020 trivial sequential steps; STSO is measured between consecutive steps in the given step ranges, and WO is the whole-run overhead outside step bodies · Promise.all(100 steps): 100 trivial no-op steps started together in a single Promise.all; Fan-out TTFS is the first of them to complete and Fan-out TTLS the last, both from the in-deployment clientStart, so their gap is the spread the runtime adds across the fan-out · paced control (100/s, 60B): the control: 300 tiny (~60B) deltas metronome-paced at 100/s — zero workload structure, so it reads the transport floor and flush cadence, and disambiguates transport-wide vs workload-specific when a replay row moves · size sweep (100/s, 160B-12KB): same pacing as the control with deltas padded in rotation across seven log-spaced sizes (~160B–12KB) — rotation decouples size from stream position, so it isolates whether chunk size causes latency · replay gateway-gpt-5.4-nano-2000t (1x): raw provider SSE cadence captured at the AI gateway boundary (gpt-5.4-nano, the most popular gateway model; per-token deltas p50 208B = the modal production chunk size), replayed exactly as measured — the typical customer's workload; its CDV is the typical customer's real delivery jitter · replay eve-gpt-5.6-sol-2000t (1x): a captured eve turn (gpt-5.6-sol, the most-used demanding eve model; ~2000 output tokens = production p50 turn length) replayed exactly as measured — eve's envelope protocol re-ships the cumulative message so sizes ramp 142B→13KB; the demanding outlier tenant's reality · replay eve-gpt-5.6-sol-2000t (2x): the same eve capture at 2x — the headroom/stress row; real fast-tier models emit the same chunk sizes at proportionally higher rate, so time compression is a faithful speed model · first chunk (pooled): every run's seq-0 RTT pooled across all stream scenarios — the first chunk precedes any workload differentiation, so pooling samples one shared stream-open path with exact percentiles
Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000teaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041
🔴 marks a percentile over its target (within target is left unmarked). Targets (p75/p90/p99, ms) — TTFS 200/300/600
All timestamps are deployment-side; runs are triggered in-deployment, so the CI runner and api.vercel.com sit outside every measured window. TTFS = start() → first step body (includes dispatch + any cold start); Fan-out TTFS/TTLS = first/last step completion of one Promise.all from the same anchor (the gap is the runtime’s fan-out spread); STSO/WO between step bodies; CRTT inside the workflow (excludes the api.vercel.com read path).
Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.
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Sim World
Simulated world deterministic testing for races. Traces
🟠 world-sim scenario book — 1 fail of 41 total
fence=per-spec
scenariooutcomeeventsvirtreplayviolations
✅ smoke-no-stepscompleted30msok0
✅ smoke-one-stepcompleted60msok0
✅ hook-at-step-startedcompleted120msok0
✅ hook-at-step-completedcompleted120msok0
✅ hook-at-hook-createdcompleted120msok0
✅ deadline-hook-winscompleted71.0hok0
✅ deadline-expirescompleted71.0hok0
✅ long-sleepcompleted1130.0dok0
✅ hook-never-arrivesstalled30msskipped0
✅ step-retries-twicecompleted102.0sok0
✅ parallel-stepscompleted90msok0
✅ hook-on-execution-statecompleted120msok0
✅ peek-hook-before-branchcompleted120msok0
✅ peek-hook-after-branchcompleted120msok0
✅ peek-hook-at-registrationcompleted120msok0
✅ race-hook-before-probecompleted120msok0
✅ race-hook-after-probecompleted120msok0
✅ race-duplicate-deliverycompleted130msok0
✅ attr-hook-before-stepcompleted110msok0
✅ attr-hook-after-stepcompleted110msok0
✅ attr-from-step-bodycompleted130msok0
✅ fork-hook-after-timeoutcompleted141.0mok0
✅ fork-hook-before-timeoutcompleted141.0mok0
✅ count-hook-after-timeoutcompleted171.0mok0
✅ count-hook-before-timeoutcompleted201.0mok0
✅ stale-read-step-count-forkcompleted201.0mok0
✅ stale-read-equal-step-countscompleted141.0mok0
✅ step-vs-step-forkcompleted120msok0
✅ step-vs-step-fork-fencedcompleted120msok0
✅ fence-catches-benign-directioncompleted125msok0
✅ in-flight-before-decisioncompleted171.0mok0
❌ in-flight-before-decision-countedcompleted171.0mok0
✅ in-flight-after-decisioncompleted192.0mok0
✅ stale-read-step-count-fork-fencedcompleted201.0mok0
✅ fork-hook-winscompleted131.0mok0
✅ fork-timeout-winscompleted131.0mok0
✅ unclaimed-payload-under-forkcompleted171.0mok0
✅ claimed-payload-under-forkcompleted171.0mok0
✅ writers-independent-step-bodiescompleted120msok0
✅ writers-scripted-tempocompleted120msok0
✅ cancel-mid-stepcancelled70msskipped0
Full trace: world-sim.txt
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peter/windows-step-registration-cleanup

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August 25, 2026 19:07
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No backport to stable for 5841558 (AI decision).
This is CI/test hardening for a failure mode that does not exist on stable: the generated __step_registrations.js that strands a deleted step fixture is main-only (on stable, step_registration appears only in the SWC plugin's Rust, and packages/next generates no such file), and the dev.test.ts changes build on main-only harness pieces (generatedStepRegistrationPath config, restoreDirectories). The tests.yml hunk likewise rewrites a Get-DevServerStatus pre-e2e probe block that stable does not have at all. Nothing here keeps stable buildable, testable, or releasable.
To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:
584155897f75e712a1c2bc199d6d12027cd18dab

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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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[core] Fail dev HMR cleanup on a stranded step registration - #3682
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[core] Fail dev HMR cleanup on a stranded step registration#3682
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Problem
Three of the last 120 Tests runs had E2E Windows Tests (node) burn its full ~30-minute

window and get cancelled with every e2e test failing on
[world-local] Queue message failed (HTTP 500), where the handlerError is a Next.js
_error page rather than anything workflow-shaped:
jobflow-route 500sstranded-import errors
9622825337310,13520,346
9621451553010,21810,886
9620285500910,28020,557
The flow route never answered a single request successfully in any of them. The dev server

log says why:
⨯ app/.well-known/workflow/v1/flow/__step_registrations.js:33:1
Module not found: Can't resolve '../../../../../workflows/source-map-warning-fixture.ts'

dev.test.ts > "should not log source map warnings for workflow node_modules imports"

writes workflows/source-map-warning-fixture.ts, which declares a 'use step' function,

and its afterEach deletes it. The generated __step_registrations.js imports every

discovered step file by path, so that deletion only stops breaking the flow route once a

rediscovery regenerates the file. When the watcher drops the unlink — which is what happens

on Windows — the generated file keeps importing a path that no longer exists, the flow route

stops compiling, and every workflow dispatch for the rest of the job gets a 500 pointing at

a fixture from a test that already passed.
The HMR log confirms nothing recovers it: 164 → 165 → 166 → 165 → 165 workflows, then

three skips and no further rediscovery. afterEach's prewarm() only waits for
workflow dev hmr: ready, printed once at startup, so nothing ever waited for the

post-deletion rediscovery in the first place.
The generated workflow bundle inlines workflow sources instead of importing them, so only
step-declaring fixtures can strand it. That is why new-workflow.ts leaks harmlessly in

the same runs while the source-map fixture is fatal.
The existing fail-fast guard cannot see this
The Windows job already probes the dev server before the long e2e run, precisely to avoid

burning the job window on a wedged server. It probes GET /api/chat, which compiles

independently of the flow route, so it reported -> 405 and let the suite run in all three

jobs.
Changes
  1. packages/core/e2e/dev.test.ts — after deleting fixtures, cleanup waits for the
    
generated step registrations to stop importing them. If they still do when the budget
    
runs out, the fixture contents are written back so the shared dev server keeps serving
    
the rest of the suite, and the hook fails naming the stranded file. CI already skips the
    
e2e suite when dev.test.ts fails, so this turns a 30-minute burn with ~10k misleading
    
500s into an immediate, accurate failure. The convergence wait runs before the
    node_modules fixture-package removal so a restored fixture still resolves its import.
  2. .github/workflows/tests.yml — the pre-e2e probe now POSTs
    /.well-known/workflow/v1/flow?__health, the SDK's own health endpoint on the route
    
that actually breaks. It returns 200 on a healthy dev server and would have returned 500
    
in all three jobs above.
Validation
Run locally against workbench/nextjs-turbopack on macOS (all 9 dev tests, so including

the flow-route HMR fuzz cases that also delete step-declaring files):
  • Happy path: the convergence wait never trips on any of the tests that delete fixtures. A
    
deletion converges in ~2s, so the watcher path itself is sound and the Windows miss is the
    
discriminator.
  • should follow Next flow-route HMR rebuild rules for body-only changes fails on macOS
    
(expected 2 to be 1 on an exact HMR log count). It fails identically with unmodified
    origin/main's dev.test.ts against the same dev server, so it is pre-existing and
    
unrelated. That case is skipped on Windows.
  • Forced-failure path (convergence budget shortened so it always expires): the hook fails
    
with the stranded path named, the fixture is restored, and
    POST /.well-known/workflow/v1/flow?__health still answers 200.
  • POST /.well-known/workflow/v1/flow?__health returns 200 on a healthy dev server and 500
    
when a path reachable from __step_registrations.js does not resolve, while
    GET /api/chat keeps answering 405 — the asymmetry the second change fixes.
The underlying Windows watcher miss is worth chasing separately; this PR stops it from

costing a whole job and makes it name itself.
Note on a related hole, not changed here
The Linux e2e-local-dev lane runs pnpm vitest run packages/core/e2e/dev.test.ts; sleep 10

and then continues into the full e2e suite, so a dev.test.ts failure there is discarded.

That lane would swallow the new hook failure too. Tightening it would newly red the lane on

pre-existing dev.test.ts flakes (the flow-route HMR fuzz case already fails on macOS

against unmodified main, see below), so it seemed worth raising separately rather than

bundling in.
@VaguelySerious@claude
[core] Fail dev HMR cleanup on a stranded step registration
62fcd0f
`dev.test.ts` fixtures that declare a `'use step'` function are imported by
path from the generated `__step_registrations.js`, so deleting one only stops
breaking the flow route once a rediscovery regenerates that file. When the dev
server's watcher drops the unlink, the generated file keeps importing a path
that no longer exists: the flow route stops compiling and every later workflow
dispatch in the job gets a 500 that names a fixture from a test that already
passed. Three of the last 120 `Tests` runs lost the whole ~30-minute Windows
e2e window this way, each with ~10k flow-route 500s and no successful dispatch.
Cleanup now waits for the generated step registrations to drop every file it
deleted. If they still reference one when the budget expires, the fixture is
written back so the shared dev server keeps serving the rest of the suite, and
the hook fails naming the stranded path. The wait runs before the node_modules
fixture-package removal so a restored fixture still resolves its import.
The pre-e2e probe moves from `GET /api/chat` to
`POST /.well-known/workflow/v1/flow?__health`. /api/chat compiles independently
of the flow route, so it answered 405 in all three jobs while every dispatch
was getting a 500.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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🦋 Changeset detected
Latest commit: d11c0dd
The changes in this PR will be included in the next version bump.
This PR includes changesets to release 16 packages
NameType
@workflow/corePatch
@workflow/buildersPatch
@workflow/cliPatch
@workflow/nextPatch
@workflow/nitroPatch
@workflow/vitestPatch
@workflow/web-sharedPatch
@workflow/webPatch
workflowPatch
@workflow/world-testingPatch
@workflow/astroPatch
@workflow/nestPatch
@workflow/rollupPatch
@workflow/sveltekitPatch
@workflow/vitePatch
@workflow/nuxtPatch
Not sure what this means? Click here to learn what changesets are.
Click here if you're a maintainer who wants to add another changeset to this PR
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The latest updates on your projects. Learn more about Vercel for GitHub.
ProjectDeploymentActionsUpdated (UTC)
example-nextjs-workflow-turbopackReadyReadyPreview, v0Aug 24, 2026 10:33pm
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🧪 E2E Test Results
❌ Some tests failed
❌ Failed E2E Tests
▲ Vercel Production (8 failed)
python-node (8 failed):
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9 | 🔍 observability
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K | 🔍 observability
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1 | 🔍 observability
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C | 🔍 observability
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C | 🔍 observability
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV | 🔍 observability
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG | 🔍 observability
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP | 🔍 observability
🌐 Cross-language Conformance (9 failed)
python (9 failed):
  • deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0TYP4EWXS4MHWKXFZN1JR0F
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP
⚠️ Flaky E2E Tests (passed on retry)
These tests failed at least once and passed on a retry. A recurring entry here is a real race worth investigating.
  • addTenWorkflow (fastify)
  • addTenWorkflow (hono)
  • addTenWorkflow (nuxt)
  • cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
  • cancelRun via CLI - cancelling a running workflow (nuxt)
  • hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (nextjs-webpack)
  • hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (nextjs-webpack)
  • sleepWinsRaceWorkflow (tanstack-start)
🛠 Infra Events (absorbed by the harness)
Platform anomalies the e2e harness detected and worked around (e.g. a run the queue never picked up, replaced by a fresh run). Clustered timestamps indicate a backend blip; a steady drip indicates a platform issue worth escalating.
32 infra events
  • cold-start-warmup · suite warmup (python) · at 22:32:26Z · abandoned wrun_41M0TYAYJT0GNGCGFT9CW8J31C · (+7 more)
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN9
  • run-pickup-stall · nullByteWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKF10GW0JY2HGZZ2K8BR
  • run-pickup-stall · sleepingWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN8
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKTR0GSK8P4JGC50Q9YT
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:32:43Z · abandoned wrun_41M0TYEKEQ0GVKJ0FPW7DV5X07
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:33:15Z · abandoned wrun_41M0TYFKB30GZV9RYEXPSVWC4S
  • run-pickup-stall · sleepingWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYP0GNT5G4RBTCFB13K
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF3N0GT1E7GFW1V9TJ21
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYS0GY7C05YYWCVAN24
  • run-pickup-stall · nullByteWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF250GVD8T6M4BGNC9MZ
  • cold-start-warmup · suite warmup (tanstack-start) · at 22:34:07Z · abandoned wrun_01M0TYGV52206SC5AEK09QTHDV
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:34:33Z · abandoned wrun_41M0TYGK1Q0GP2X8Z95ZQRRF08
  • cold-start-warmup · suite warmup (python) · at 22:35:18Z · abandoned wrun_01M0TYG6112GWK343TTH7VNV7D · (+7 more)
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36E
  • run-pickup-stall · sleepingWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5VB4BEN37GS66N59YK
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5Y18NPGYQK6XKMNBJY
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36D
  • run-pickup-stall · nullByteWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV60YRZTH9DG0JNDANBH
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSJYNGNK851MQP1JB09
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSGB77J7W5E13A3R263
  • run-pickup-stall · sleepingWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSM1WW7VT6JAS9B0VEX
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSQ61EMZQSZ849JNHA7
  • run-pickup-stall · nullByteWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSR4ER537QZBJ79SN2G
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:36:55Z · abandoned wrun_41M0TYK6V80GQ8NYJDE1PPJBXH
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:36:55Z · abandoned wrun_41M0TYKAY70GYG61T79VHX87WA
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGD6NDH7M075CNB00CER
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDAM3PHNF2JA81T8P7Z
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDH2ZVXYM64QF0HSDRM
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRQC396P9TA2NFEF1YW
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRY07WYKZTT81X3CSEA
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:38:33Z · abandoned wrun_01M0TYSB0M52SKJN6P09C9FJ4R
E2E Test Summary
Summary
PassedFailedSkippedTotal
❌ ▲ Vercel Production357087424320
✅ 💻 Local Development392205584480
✅ 📦 Local Production392205584480
✅ 🐘 Local Postgres392205584480
✅ 🪟 Windows32000320
❌ 🌐 Cross-language Conformance09132141
✅ vercel-http-transport8170143960
✅ vercel-multi-region270027
✅ vercel-ws-transport553087640
Total1705317277819848
Details by Category
❌ ▲ Vercel Production
AppPassedFailedSkipped
✅ astro-node132028
✅ astro-quickjs132028
✅ example-node132028
✅ example-quickjs132028
✅ express-node132028
✅ express-quickjs132028
✅ fastify-node132028
✅ fastify-quickjs132028
✅ hono-node132028
✅ hono-quickjs132028
✅ nest-node132028
✅ nest-quickjs132028
✅ nextjs-turbopack-node15703
✅ nextjs-turbopack-quickjs15703
✅ nextjs-webpack-node15703
✅ nextjs-webpack-quickjs15703
✅ nitro-node132028
✅ nitro-quickjs132028
✅ nuxt-node132028
✅ nuxt-quickjs132028
❌ python-node08152
✅ sveltekit-node15109
✅ sveltekit-quickjs15109
✅ tanstack-start-node132028
✅ tanstack-start-quickjs132028
✅ vite-node132028
✅ vite-quickjs132028
✅ 💻 Local Development
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 📦 Local Production
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🐘 Local Postgres
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🪟 Windows
AppPassedFailedSkipped
✅ nextjs-turbopack-node16000
✅ nextjs-turbopack-quickjs16000
❌ 🌐 Cross-language Conformance
AppPassedFailedSkipped
❌ python09132
✅ vercel-http-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ hono132028
✅ nextjs-turbopack15703
✅ nitro132028
✅ vite132028
✅ vercel-multi-region
AppPassedFailedSkipped
✅ nextjs-turbopack2700
✅ vercel-ws-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ nextjs-turbopack15703
✅ vite132028
📋 View full workflow run
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📊 Workflow Benchmarks
commit d11c0dd · Mon, 24 Aug 2026 22:55:03 GMT · run logs
Backend: vercel · app: nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep246 (-75%) 💚1346 🔴 (+22%) 🔻1384 🔴 (+20%) 🔻1484 🔴 (+18%) 🔻30
TTFSstream222 (-69%) 💚1328 🔴 (+21%) 🔻1400 🔴 (+26%) 🔻1432 🔴 (+11%)30
TTFShook + stream1264 (-8.0%)1646 🔴 (+12%)1722 🔴 (+14%)2321 🔴 (+45%) 🔻30
Fan-out TTFSPromise.all(100 steps)645 (-0.8%)1882 (+10%)2135 (+19%) 🔻2343 (+20%) 🔻10
Fan-out TTLSPromise.all(100 steps)1841 (-4.7%)3816 (+20%) 🔻5084 (+55%) 🔻5570 (-34%) 💚10
STSO1020 steps (inline)69 (-34%) 💚140 (-5.4%)164 (-2.4%)275 (+26%) 🔻1019
WO1020 steps140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)1
CRTTfirst chunk (pooled)107 (+22%) 🔻171 (+38%) 🔻260 (+35%) 🔻274 (-56%) 💚28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+25%)256 (+97%)513 (+142%)967 (+27%)279 (+95%)10
size sweep (100/s, 160B-12KB)150 (+33%)164 (+15%)275 (+47%)495 (-56%)195 (+42%)10
replay gateway-gpt-5.4-nano-2000t (1x)131 (+7%)532 (-18%)706 (-79%)911 (-81%)203 (-6%)3
replay eve-gpt-5.6-sol-2000t (1x)216 (+83%)168 (+25%)261 (+54%)1122 (+225%)761 (+191%)2
replay eve-gpt-5.6-sol-2000t (2x)150 (+22%)207 (+13%)274 (+4%)691 (+25%)268 (+18%)3
📈 STSO distribution vs main (inline / queue-hop histograms)
1020 steps (inline)
Cumulative STSO time: main 147417ms → this run 140462ms (Δ -6955ms, -5%)
 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████░┃ main 785 this 848 +63
150-200 ms ███┃██ main 216 this 143 -73
200-250 ms ┃ main 14 this 11 -3
250-300 ms ┃ main 4 this 9 +5
300-350 ms ┃ main 0 this 5 +5
350-400 ms ┃ main 0 this 1 +1
400-450 ms ┃ main 0 this 1 +1

📈 CRTT drill-down vs main (RTT distributions & profiles)
variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▃█▃▁··· 175.1 (+46%) 135 (+27%) 513 (+142%) 967 (+27%) 3000
sweep ······▃█▂▁··· 136.8 (+11%) 122 (+11%) 275 (+47%) 495 (-56%) 3000
gw 1x ·····▁▄█▃▂··· 203.3 (-39%) 119 (+18%) 706 (-79%) 911 (-81%) 5295
eve 1x ·····▁▃█▂▁▁·· 171.8 (+55%) 129 (+42%) 261 (+54%) 1122 (+225%) 5186
eve 2x ·····▁▂█▃▁··· 167.7 (+20%) 149 (+16%) 274 (+4%) 691 (+25%) 7779

RTT over stream progress (avg per tenth of stream, bars scaled min→max):
control ▅█▄▆▃▄▁▆▅█ 145–199ms
sweep █▆▂▁▂▅▃▁▃▂ 116–178ms
gw 1x ██▄▄▅▁▂▄▇▅ 122–275ms
eve 1x ▂▂▃▂▁▁▄█▁▁ 121–326ms
eve 2x ▃▁▁▁▁▂▅██▂ 142–224ms

RTT by chunk size (avg per log size bin, ~160B → ~12KB serialized, bars scaled min→max):
sweep ▁▅█▅▅▂▃ 136–138ms

Delivery jitter over stream progress (avg positive CDV per tenth of stream, bars scaled min→max):
control ▄▁▁▆▆▃▆▄█▅ 34–56ms
sweep ▁▃▃▃▆▄▆▄█▂ 44–59ms
gw 1x █▄▂▂▃▁▄▃▆▃ 38–71ms
eve 1x ▅▆▆▅▃▁█▅▃▃ 24–39ms
eve 2x █▇▁▃▆▅█▃▄▆ 22–36ms

📜 Previous results (2)
47501c6
Fri, 21 Aug 2026 23:12:41 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1314 (+22%) 🔻1396 🔴 (+21%) 🔻1428 🔴 (+14%)1481 🔴 (+3.6%)30
TTFSstream270 (-75%) 💚1352 🔴 (+12%)1378 🔴 (+7.1%)1389 🔴 (-3.9%)30
TTFShook + stream1534 (+45%) 🔻1659 🔴 (+14%)1766 🔴 (+17%) 🔻2433 🔴 (+57%) 🔻30
Fan-out TTFSPromise.all(100 steps)568 (-4.1%)2033 (+28%) 🔻2052 (+24%) 🔻2111 (+27%) 🔻10
Fan-out TTLSPromise.all(100 steps)1699 (+5.1%)3860 (+28%) 🔻4036 (+12%)4573 (+16%) 🔻10
STSO1020 steps (inline)114 (-24%) 💚168 (-24%) 💚189 (-27%) 💚344 (-36%) 💚1019
WO1020 steps169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚1
CRTTfirst chunk (pooled)99 (+4.2%)152 (+2.7%)189 (+8.6%)376 (+62%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+9%)143 (-23%)186 (-27%)402 (+6%)110 (-35%)10
size sweep (100/s, 160B-12KB)125 (+1%)151 (-18%)195 (-42%)279 (-46%)99.5 (-25%)10
replay gateway-gpt-5.4-nano-2000t (1x)152 (+26%)189 (-74%)414 (-87%)757 (-84%)466 (-86%)3
replay eve-gpt-5.6-sol-2000t (1x)159 (+31%)148 (-8%)186 (-10%)287 (-20%)296 (-2%)2
replay eve-gpt-5.6-sol-2000t (2x)135 (-13%)200 (-38%)268 (-73%)380 (-83%)246 (-38%)3
62fcd0f
Wed, 19 Aug 2026 23:10:40 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1287 (+24%) 🔻1401 🔴 (+19%) 🔻1442 🔴 (+17%) 🔻1732 🔴 (+4.1%)30
TTFSstream1260 (+25%) 🔻1388 🔴 (+25%) 🔻1428 🔴 (+25%) 🔻1742 🔴 (+49%) 🔻30
TTFShook + stream538 (-58%) 💚1644 🔴 (+15%)1690 🔴 (+15%)1986 🔴 (+26%) 🔻30
Fan-out TTFSPromise.all(100 steps)527 (-7.9%)829 (-16%) 💚986 (-45%) 💚2498 (+38%) 🔻10
Fan-out TTLSPromise.all(100 steps)4804 (+1.2%)8742 (+6.0%)9471 (-13%)10733 (-19%) 💚10
STSO1020 steps (inline)117 (-5.6%)159 (-35%) 💚185 (-37%) 💚303 (-40%) 💚1019
WO1020 steps158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚1
CRTTfirst chunk (pooled)101 (-4.7%)175 (+3.6%)372 (+84%) 🔻3550 (+770%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)115 (-20%)131 (-27%)168 (-42%)335 (-36%)96.5 (-32%)10
size sweep (100/s, 160B-12KB)127 (-9%)135 (-26%)172 (-32%)310 (-31%)134 (-14%)10
replay gateway-gpt-5.4-nano-2000t (1x)204 (+37%)139 (-4%)230 (+8%)675 (-3%)293 (+18%)3
replay eve-gpt-5.6-sol-2000t (1x)1837 (+1128%)140 (-5%)193 (±0%)3960 (+1082%)2212 (+683%)2
replay eve-gpt-5.6-sol-2000t (2x)372 (+120%)242 (+12%)468 (+23%)1195 (±0%)226 (-43%)3
ℹ️ Metric definitions & methodology
Streams: first-chunk RTT (the stream-open path, before any buffering/backpressure), CRTT percentiles, and worst delivery stall (CDV max). Cells are medians across iterations; per-run values in the artifacts. No 🔴/🟢 marks until targets attach.
The collapsed STSO distribution section above buckets every step gap, split inline (same warm process — pure framework overhead) vs queue-hop (fresh process — dispatch, reinit, replay). █ = main, ┃ = this run, ░ = fill.
The collapsed CRTT drill-down: per-variant RTT histograms (fixed log bins, · = empty) and mean RTT/positive-CDV profile lines over stream progress and chunk size. Histograms, avgs, and profiles merge exactly across runs; p50–p99 are percentile-of-percentiles. Per-index rows live in the artifacts.
Best/P75/P90/P99 deltas compare against the most recent benchmark run on main at the time of this run. 🔻 flags a delta worse than +15%, 💚 one better than −15%.
Metrics — TTFS: time to first step body (in-deployment start() → first step body) · Fan-out TTFS: fan-out time to first step (in-deployment start() → first of the parallel step bodies to complete) · Fan-out TTLS: fan-out time to last step (in-deployment start() → last of the parallel step bodies to complete, i.e. when the Promise.all resolves) · STSO: step-to-step overhead (gap between consecutive step bodies) · WO: workflow overhead (whole-run time outside step bodies, in-deployment anchored) · CRTT: chunk round-trip time (per-chunk write → read latency, one clock domain: deployment → stream backend → same deployment) · CDV: chunk delay variation / delivery jitter (inter-arrival gap minus inter-write gap per seq-adjacent pair; skew-free; the row is each run's MAX positive value, so one stall moves it)
Scenarios — step: one trivial no-op step, no stream; no hooks, so the run stays in turbo mode (in-process fast path) · stream: one streaming step; no hooks, so the run stays in turbo mode (in-process fast path) · hook + stream: registers a hook before one step, which exits turbo mode (dispatch path) · 1020 steps: 1020 trivial sequential steps; STSO is measured between consecutive steps in the given step ranges, and WO is the whole-run overhead outside step bodies · Promise.all(100 steps): 100 trivial no-op steps started together in a single Promise.all; Fan-out TTFS is the first of them to complete and Fan-out TTLS the last, both from the in-deployment clientStart, so their gap is the spread the runtime adds across the fan-out · paced control (100/s, 60B): the control: 300 tiny (~60B) deltas metronome-paced at 100/s — zero workload structure, so it reads the transport floor and flush cadence, and disambiguates transport-wide vs workload-specific when a replay row moves · size sweep (100/s, 160B-12KB): same pacing as the control with deltas padded in rotation across seven log-spaced sizes (~160B–12KB) — rotation decouples size from stream position, so it isolates whether chunk size causes latency · replay gateway-gpt-5.4-nano-2000t (1x): raw provider SSE cadence captured at the AI gateway boundary (gpt-5.4-nano, the most popular gateway model; per-token deltas p50 208B = the modal production chunk size), replayed exactly as measured — the typical customer's workload; its CDV is the typical customer's real delivery jitter · replay eve-gpt-5.6-sol-2000t (1x): a captured eve turn (gpt-5.6-sol, the most-used demanding eve model; ~2000 output tokens = production p50 turn length) replayed exactly as measured — eve's envelope protocol re-ships the cumulative message so sizes ramp 142B→13KB; the demanding outlier tenant's reality · replay eve-gpt-5.6-sol-2000t (2x): the same eve capture at 2x — the headroom/stress row; real fast-tier models emit the same chunk sizes at proportionally higher rate, so time compression is a faithful speed model · first chunk (pooled): every run's seq-0 RTT pooled across all stream scenarios — the first chunk precedes any workload differentiation, so pooling samples one shared stream-open path with exact percentiles
Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000teaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041
🔴 marks a percentile over its target (within target is left unmarked). Targets (p75/p90/p99, ms) — TTFS 200/300/600
All timestamps are deployment-side; runs are triggered in-deployment, so the CI runner and api.vercel.com sit outside every measured window. TTFS = start() → first step body (includes dispatch + any cold start); Fan-out TTFS/TTLS = first/last step completion of one Promise.all from the same anchor (the gap is the runtime’s fan-out spread); STSO/WO between step bodies; CRTT inside the workflow (excludes the api.vercel.com read path).
Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.
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Sim World
Simulated world deterministic testing for races. Traces
🟠 world-sim scenario book — 1 fail of 41 total
fence=per-spec
scenariooutcomeeventsvirtreplayviolations
✅ smoke-no-stepscompleted30msok0
✅ smoke-one-stepcompleted60msok0
✅ hook-at-step-startedcompleted120msok0
✅ hook-at-step-completedcompleted120msok0
✅ hook-at-hook-createdcompleted120msok0
✅ deadline-hook-winscompleted71.0hok0
✅ deadline-expirescompleted71.0hok0
✅ long-sleepcompleted1130.0dok0
✅ hook-never-arrivesstalled30msskipped0
✅ step-retries-twicecompleted102.0sok0
✅ parallel-stepscompleted90msok0
✅ hook-on-execution-statecompleted120msok0
✅ peek-hook-before-branchcompleted120msok0
✅ peek-hook-after-branchcompleted120msok0
✅ peek-hook-at-registrationcompleted120msok0
✅ race-hook-before-probecompleted120msok0
✅ race-hook-after-probecompleted120msok0
✅ race-duplicate-deliverycompleted130msok0
✅ attr-hook-before-stepcompleted110msok0
✅ attr-hook-after-stepcompleted110msok0
✅ attr-from-step-bodycompleted130msok0
✅ fork-hook-after-timeoutcompleted141.0mok0
✅ fork-hook-before-timeoutcompleted141.0mok0
✅ count-hook-after-timeoutcompleted171.0mok0
✅ count-hook-before-timeoutcompleted201.0mok0
✅ stale-read-step-count-forkcompleted201.0mok0
✅ stale-read-equal-step-countscompleted141.0mok0
✅ step-vs-step-forkcompleted120msok0
✅ step-vs-step-fork-fencedcompleted120msok0
✅ fence-catches-benign-directioncompleted125msok0
✅ in-flight-before-decisioncompleted171.0mok0
❌ in-flight-before-decision-countedcompleted171.0mok0
✅ in-flight-after-decisioncompleted192.0mok0
✅ stale-read-step-count-fork-fencedcompleted201.0mok0
✅ fork-hook-winscompleted131.0mok0
✅ fork-timeout-winscompleted131.0mok0
✅ unclaimed-payload-under-forkcompleted171.0mok0
✅ claimed-payload-under-forkcompleted171.0mok0
✅ writers-independent-step-bodiescompleted120msok0
✅ writers-scripted-tempocompleted120msok0
✅ cancel-mid-stepcancelled70msskipped0
Full trace: world-sim.txt
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marked this pull request as ready for review
August 21, 2026 22:48
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merged commit 5841558
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deleted the

peter/windows-step-registration-cleanup

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August 25, 2026 19:07
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No backport to stable for 5841558 (AI decision).
This is CI/test hardening for a failure mode that does not exist on stable: the generated __step_registrations.js that strands a deleted step fixture is main-only (on stable, step_registration appears only in the SWC plugin's Rust, and packages/next generates no such file), and the dev.test.ts changes build on main-only harness pieces (generatedStepRegistrationPath config, restoreDirectories). The tests.yml hunk likewise rewrites a Get-DevServerStatus pre-e2e probe block that stable does not have at all. Nothing here keeps stable buildable, testable, or releasable.
To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:
584155897f75e712a1c2bc199d6d12027cd18dab

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@VaguelySerious@alangenfeld

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injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
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[core] Fail dev HMR cleanup on a stranded step registration - #3682
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peter/windows-step-registration-cleanup
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[core] Fail dev HMR cleanup on a stranded step registration#3682
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Problem
Three of the last 120 Tests runs had E2E Windows Tests (node) burn its full ~30-minute

window and get cancelled with every e2e test failing on
[world-local] Queue message failed (HTTP 500), where the handlerError is a Next.js
_error page rather than anything workflow-shaped:
jobflow-route 500sstranded-import errors
9622825337310,13520,346
9621451553010,21810,886
9620285500910,28020,557
The flow route never answered a single request successfully in any of them. The dev server

log says why:
⨯ app/.well-known/workflow/v1/flow/__step_registrations.js:33:1
Module not found: Can't resolve '../../../../../workflows/source-map-warning-fixture.ts'

dev.test.ts > "should not log source map warnings for workflow node_modules imports"

writes workflows/source-map-warning-fixture.ts, which declares a 'use step' function,

and its afterEach deletes it. The generated __step_registrations.js imports every

discovered step file by path, so that deletion only stops breaking the flow route once a

rediscovery regenerates the file. When the watcher drops the unlink — which is what happens

on Windows — the generated file keeps importing a path that no longer exists, the flow route

stops compiling, and every workflow dispatch for the rest of the job gets a 500 pointing at

a fixture from a test that already passed.
The HMR log confirms nothing recovers it: 164 → 165 → 166 → 165 → 165 workflows, then

three skips and no further rediscovery. afterEach's prewarm() only waits for
workflow dev hmr: ready, printed once at startup, so nothing ever waited for the

post-deletion rediscovery in the first place.
The generated workflow bundle inlines workflow sources instead of importing them, so only
step-declaring fixtures can strand it. That is why new-workflow.ts leaks harmlessly in

the same runs while the source-map fixture is fatal.
The existing fail-fast guard cannot see this
The Windows job already probes the dev server before the long e2e run, precisely to avoid

burning the job window on a wedged server. It probes GET /api/chat, which compiles

independently of the flow route, so it reported -> 405 and let the suite run in all three

jobs.
Changes
  1. packages/core/e2e/dev.test.ts — after deleting fixtures, cleanup waits for the
    
generated step registrations to stop importing them. If they still do when the budget
    
runs out, the fixture contents are written back so the shared dev server keeps serving
    
the rest of the suite, and the hook fails naming the stranded file. CI already skips the
    
e2e suite when dev.test.ts fails, so this turns a 30-minute burn with ~10k misleading
    
500s into an immediate, accurate failure. The convergence wait runs before the
    node_modules fixture-package removal so a restored fixture still resolves its import.
  2. .github/workflows/tests.yml — the pre-e2e probe now POSTs
    /.well-known/workflow/v1/flow?__health, the SDK's own health endpoint on the route
    
that actually breaks. It returns 200 on a healthy dev server and would have returned 500
    
in all three jobs above.
Validation
Run locally against workbench/nextjs-turbopack on macOS (all 9 dev tests, so including

the flow-route HMR fuzz cases that also delete step-declaring files):
  • Happy path: the convergence wait never trips on any of the tests that delete fixtures. A
    
deletion converges in ~2s, so the watcher path itself is sound and the Windows miss is the
    
discriminator.
  • should follow Next flow-route HMR rebuild rules for body-only changes fails on macOS
    
(expected 2 to be 1 on an exact HMR log count). It fails identically with unmodified
    origin/main's dev.test.ts against the same dev server, so it is pre-existing and
    
unrelated. That case is skipped on Windows.
  • Forced-failure path (convergence budget shortened so it always expires): the hook fails
    
with the stranded path named, the fixture is restored, and
    POST /.well-known/workflow/v1/flow?__health still answers 200.
  • POST /.well-known/workflow/v1/flow?__health returns 200 on a healthy dev server and 500
    
when a path reachable from __step_registrations.js does not resolve, while
    GET /api/chat keeps answering 405 — the asymmetry the second change fixes.
The underlying Windows watcher miss is worth chasing separately; this PR stops it from

costing a whole job and makes it name itself.
Note on a related hole, not changed here
The Linux e2e-local-dev lane runs pnpm vitest run packages/core/e2e/dev.test.ts; sleep 10

and then continues into the full e2e suite, so a dev.test.ts failure there is discarded.

That lane would swallow the new hook failure too. Tightening it would newly red the lane on

pre-existing dev.test.ts flakes (the flow-route HMR fuzz case already fails on macOS

against unmodified main, see below), so it seemed worth raising separately rather than

bundling in.
@VaguelySerious@claude
[core] Fail dev HMR cleanup on a stranded step registration
62fcd0f
`dev.test.ts` fixtures that declare a `'use step'` function are imported by
path from the generated `__step_registrations.js`, so deleting one only stops
breaking the flow route once a rediscovery regenerates that file. When the dev
server's watcher drops the unlink, the generated file keeps importing a path
that no longer exists: the flow route stops compiling and every later workflow
dispatch in the job gets a 500 that names a fixture from a test that already
passed. Three of the last 120 `Tests` runs lost the whole ~30-minute Windows
e2e window this way, each with ~10k flow-route 500s and no successful dispatch.
Cleanup now waits for the generated step registrations to drop every file it
deleted. If they still reference one when the budget expires, the fixture is
written back so the shared dev server keeps serving the rest of the suite, and
the hook fails naming the stranded path. The wait runs before the node_modules
fixture-package removal so a restored fixture still resolves its import.
The pre-e2e probe moves from `GET /api/chat` to
`POST /.well-known/workflow/v1/flow?__health`. /api/chat compiles independently
of the flow route, so it answered 405 in all three jobs while every dispatch
was getting a 500.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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🦋 Changeset detected
Latest commit: d11c0dd
The changes in this PR will be included in the next version bump.
This PR includes changesets to release 16 packages
NameType
@workflow/corePatch
@workflow/buildersPatch
@workflow/cliPatch
@workflow/nextPatch
@workflow/nitroPatch
@workflow/vitestPatch
@workflow/web-sharedPatch
@workflow/webPatch
workflowPatch
@workflow/world-testingPatch
@workflow/astroPatch
@workflow/nestPatch
@workflow/rollupPatch
@workflow/sveltekitPatch
@workflow/vitePatch
@workflow/nuxtPatch
Not sure what this means? Click here to learn what changesets are.
Click here if you're a maintainer who wants to add another changeset to this PR
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The latest updates on your projects. Learn more about Vercel for GitHub.
ProjectDeploymentActionsUpdated (UTC)
example-nextjs-workflow-turbopackReadyReadyPreview, v0Aug 24, 2026 10:33pm
example-nextjs-workflow-webpackReadyReadyPreview, v0Aug 24, 2026 10:33pm
example-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-astro-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-express-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-fastify-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-hono-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-nestjs-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-nitro-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
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workbench-python-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-sveltekit-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
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workbench-vite-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workflow-docsReadyReadyPreview, v0Aug 24, 2026 10:33pm
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🧪 E2E Test Results
❌ Some tests failed
❌ Failed E2E Tests
▲ Vercel Production (8 failed)
python-node (8 failed):
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9 | 🔍 observability
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K | 🔍 observability
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1 | 🔍 observability
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C | 🔍 observability
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C | 🔍 observability
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV | 🔍 observability
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG | 🔍 observability
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP | 🔍 observability
🌐 Cross-language Conformance (9 failed)
python (9 failed):
  • deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0TYP4EWXS4MHWKXFZN1JR0F
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP
⚠️ Flaky E2E Tests (passed on retry)
These tests failed at least once and passed on a retry. A recurring entry here is a real race worth investigating.
  • addTenWorkflow (fastify)
  • addTenWorkflow (hono)
  • addTenWorkflow (nuxt)
  • cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
  • cancelRun via CLI - cancelling a running workflow (nuxt)
  • hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (nextjs-webpack)
  • hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (nextjs-webpack)
  • sleepWinsRaceWorkflow (tanstack-start)
🛠 Infra Events (absorbed by the harness)
Platform anomalies the e2e harness detected and worked around (e.g. a run the queue never picked up, replaced by a fresh run). Clustered timestamps indicate a backend blip; a steady drip indicates a platform issue worth escalating.
32 infra events
  • cold-start-warmup · suite warmup (python) · at 22:32:26Z · abandoned wrun_41M0TYAYJT0GNGCGFT9CW8J31C · (+7 more)
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN9
  • run-pickup-stall · nullByteWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKF10GW0JY2HGZZ2K8BR
  • run-pickup-stall · sleepingWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN8
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKTR0GSK8P4JGC50Q9YT
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:32:43Z · abandoned wrun_41M0TYEKEQ0GVKJ0FPW7DV5X07
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:33:15Z · abandoned wrun_41M0TYFKB30GZV9RYEXPSVWC4S
  • run-pickup-stall · sleepingWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYP0GNT5G4RBTCFB13K
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF3N0GT1E7GFW1V9TJ21
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYS0GY7C05YYWCVAN24
  • run-pickup-stall · nullByteWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF250GVD8T6M4BGNC9MZ
  • cold-start-warmup · suite warmup (tanstack-start) · at 22:34:07Z · abandoned wrun_01M0TYGV52206SC5AEK09QTHDV
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:34:33Z · abandoned wrun_41M0TYGK1Q0GP2X8Z95ZQRRF08
  • cold-start-warmup · suite warmup (python) · at 22:35:18Z · abandoned wrun_01M0TYG6112GWK343TTH7VNV7D · (+7 more)
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36E
  • run-pickup-stall · sleepingWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5VB4BEN37GS66N59YK
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5Y18NPGYQK6XKMNBJY
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36D
  • run-pickup-stall · nullByteWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV60YRZTH9DG0JNDANBH
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSJYNGNK851MQP1JB09
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSGB77J7W5E13A3R263
  • run-pickup-stall · sleepingWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSM1WW7VT6JAS9B0VEX
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSQ61EMZQSZ849JNHA7
  • run-pickup-stall · nullByteWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSR4ER537QZBJ79SN2G
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:36:55Z · abandoned wrun_41M0TYK6V80GQ8NYJDE1PPJBXH
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:36:55Z · abandoned wrun_41M0TYKAY70GYG61T79VHX87WA
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGD6NDH7M075CNB00CER
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDAM3PHNF2JA81T8P7Z
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDH2ZVXYM64QF0HSDRM
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRQC396P9TA2NFEF1YW
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRY07WYKZTT81X3CSEA
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:38:33Z · abandoned wrun_01M0TYSB0M52SKJN6P09C9FJ4R
E2E Test Summary
Summary
PassedFailedSkippedTotal
❌ ▲ Vercel Production357087424320
✅ 💻 Local Development392205584480
✅ 📦 Local Production392205584480
✅ 🐘 Local Postgres392205584480
✅ 🪟 Windows32000320
❌ 🌐 Cross-language Conformance09132141
✅ vercel-http-transport8170143960
✅ vercel-multi-region270027
✅ vercel-ws-transport553087640
Total1705317277819848
Details by Category
❌ ▲ Vercel Production
AppPassedFailedSkipped
✅ astro-node132028
✅ astro-quickjs132028
✅ example-node132028
✅ example-quickjs132028
✅ express-node132028
✅ express-quickjs132028
✅ fastify-node132028
✅ fastify-quickjs132028
✅ hono-node132028
✅ hono-quickjs132028
✅ nest-node132028
✅ nest-quickjs132028
✅ nextjs-turbopack-node15703
✅ nextjs-turbopack-quickjs15703
✅ nextjs-webpack-node15703
✅ nextjs-webpack-quickjs15703
✅ nitro-node132028
✅ nitro-quickjs132028
✅ nuxt-node132028
✅ nuxt-quickjs132028
❌ python-node08152
✅ sveltekit-node15109
✅ sveltekit-quickjs15109
✅ tanstack-start-node132028
✅ tanstack-start-quickjs132028
✅ vite-node132028
✅ vite-quickjs132028
✅ 💻 Local Development
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 📦 Local Production
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🐘 Local Postgres
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🪟 Windows
AppPassedFailedSkipped
✅ nextjs-turbopack-node16000
✅ nextjs-turbopack-quickjs16000
❌ 🌐 Cross-language Conformance
AppPassedFailedSkipped
❌ python09132
✅ vercel-http-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ hono132028
✅ nextjs-turbopack15703
✅ nitro132028
✅ vite132028
✅ vercel-multi-region
AppPassedFailedSkipped
✅ nextjs-turbopack2700
✅ vercel-ws-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ nextjs-turbopack15703
✅ vite132028
📋 View full workflow run
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📊 Workflow Benchmarks
commit d11c0dd · Mon, 24 Aug 2026 22:55:03 GMT · run logs
Backend: vercel · app: nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep246 (-75%) 💚1346 🔴 (+22%) 🔻1384 🔴 (+20%) 🔻1484 🔴 (+18%) 🔻30
TTFSstream222 (-69%) 💚1328 🔴 (+21%) 🔻1400 🔴 (+26%) 🔻1432 🔴 (+11%)30
TTFShook + stream1264 (-8.0%)1646 🔴 (+12%)1722 🔴 (+14%)2321 🔴 (+45%) 🔻30
Fan-out TTFSPromise.all(100 steps)645 (-0.8%)1882 (+10%)2135 (+19%) 🔻2343 (+20%) 🔻10
Fan-out TTLSPromise.all(100 steps)1841 (-4.7%)3816 (+20%) 🔻5084 (+55%) 🔻5570 (-34%) 💚10
STSO1020 steps (inline)69 (-34%) 💚140 (-5.4%)164 (-2.4%)275 (+26%) 🔻1019
WO1020 steps140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)1
CRTTfirst chunk (pooled)107 (+22%) 🔻171 (+38%) 🔻260 (+35%) 🔻274 (-56%) 💚28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+25%)256 (+97%)513 (+142%)967 (+27%)279 (+95%)10
size sweep (100/s, 160B-12KB)150 (+33%)164 (+15%)275 (+47%)495 (-56%)195 (+42%)10
replay gateway-gpt-5.4-nano-2000t (1x)131 (+7%)532 (-18%)706 (-79%)911 (-81%)203 (-6%)3
replay eve-gpt-5.6-sol-2000t (1x)216 (+83%)168 (+25%)261 (+54%)1122 (+225%)761 (+191%)2
replay eve-gpt-5.6-sol-2000t (2x)150 (+22%)207 (+13%)274 (+4%)691 (+25%)268 (+18%)3
📈 STSO distribution vs main (inline / queue-hop histograms)
1020 steps (inline)
Cumulative STSO time: main 147417ms → this run 140462ms (Δ -6955ms, -5%)
 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████░┃ main 785 this 848 +63
150-200 ms ███┃██ main 216 this 143 -73
200-250 ms ┃ main 14 this 11 -3
250-300 ms ┃ main 4 this 9 +5
300-350 ms ┃ main 0 this 5 +5
350-400 ms ┃ main 0 this 1 +1
400-450 ms ┃ main 0 this 1 +1

📈 CRTT drill-down vs main (RTT distributions & profiles)
variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▃█▃▁··· 175.1 (+46%) 135 (+27%) 513 (+142%) 967 (+27%) 3000
sweep ······▃█▂▁··· 136.8 (+11%) 122 (+11%) 275 (+47%) 495 (-56%) 3000
gw 1x ·····▁▄█▃▂··· 203.3 (-39%) 119 (+18%) 706 (-79%) 911 (-81%) 5295
eve 1x ·····▁▃█▂▁▁·· 171.8 (+55%) 129 (+42%) 261 (+54%) 1122 (+225%) 5186
eve 2x ·····▁▂█▃▁··· 167.7 (+20%) 149 (+16%) 274 (+4%) 691 (+25%) 7779

RTT over stream progress (avg per tenth of stream, bars scaled min→max):
control ▅█▄▆▃▄▁▆▅█ 145–199ms
sweep █▆▂▁▂▅▃▁▃▂ 116–178ms
gw 1x ██▄▄▅▁▂▄▇▅ 122–275ms
eve 1x ▂▂▃▂▁▁▄█▁▁ 121–326ms
eve 2x ▃▁▁▁▁▂▅██▂ 142–224ms

RTT by chunk size (avg per log size bin, ~160B → ~12KB serialized, bars scaled min→max):
sweep ▁▅█▅▅▂▃ 136–138ms

Delivery jitter over stream progress (avg positive CDV per tenth of stream, bars scaled min→max):
control ▄▁▁▆▆▃▆▄█▅ 34–56ms
sweep ▁▃▃▃▆▄▆▄█▂ 44–59ms
gw 1x █▄▂▂▃▁▄▃▆▃ 38–71ms
eve 1x ▅▆▆▅▃▁█▅▃▃ 24–39ms
eve 2x █▇▁▃▆▅█▃▄▆ 22–36ms

📜 Previous results (2)
47501c6
Fri, 21 Aug 2026 23:12:41 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1314 (+22%) 🔻1396 🔴 (+21%) 🔻1428 🔴 (+14%)1481 🔴 (+3.6%)30
TTFSstream270 (-75%) 💚1352 🔴 (+12%)1378 🔴 (+7.1%)1389 🔴 (-3.9%)30
TTFShook + stream1534 (+45%) 🔻1659 🔴 (+14%)1766 🔴 (+17%) 🔻2433 🔴 (+57%) 🔻30
Fan-out TTFSPromise.all(100 steps)568 (-4.1%)2033 (+28%) 🔻2052 (+24%) 🔻2111 (+27%) 🔻10
Fan-out TTLSPromise.all(100 steps)1699 (+5.1%)3860 (+28%) 🔻4036 (+12%)4573 (+16%) 🔻10
STSO1020 steps (inline)114 (-24%) 💚168 (-24%) 💚189 (-27%) 💚344 (-36%) 💚1019
WO1020 steps169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚1
CRTTfirst chunk (pooled)99 (+4.2%)152 (+2.7%)189 (+8.6%)376 (+62%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+9%)143 (-23%)186 (-27%)402 (+6%)110 (-35%)10
size sweep (100/s, 160B-12KB)125 (+1%)151 (-18%)195 (-42%)279 (-46%)99.5 (-25%)10
replay gateway-gpt-5.4-nano-2000t (1x)152 (+26%)189 (-74%)414 (-87%)757 (-84%)466 (-86%)3
replay eve-gpt-5.6-sol-2000t (1x)159 (+31%)148 (-8%)186 (-10%)287 (-20%)296 (-2%)2
replay eve-gpt-5.6-sol-2000t (2x)135 (-13%)200 (-38%)268 (-73%)380 (-83%)246 (-38%)3
62fcd0f
Wed, 19 Aug 2026 23:10:40 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1287 (+24%) 🔻1401 🔴 (+19%) 🔻1442 🔴 (+17%) 🔻1732 🔴 (+4.1%)30
TTFSstream1260 (+25%) 🔻1388 🔴 (+25%) 🔻1428 🔴 (+25%) 🔻1742 🔴 (+49%) 🔻30
TTFShook + stream538 (-58%) 💚1644 🔴 (+15%)1690 🔴 (+15%)1986 🔴 (+26%) 🔻30
Fan-out TTFSPromise.all(100 steps)527 (-7.9%)829 (-16%) 💚986 (-45%) 💚2498 (+38%) 🔻10
Fan-out TTLSPromise.all(100 steps)4804 (+1.2%)8742 (+6.0%)9471 (-13%)10733 (-19%) 💚10
STSO1020 steps (inline)117 (-5.6%)159 (-35%) 💚185 (-37%) 💚303 (-40%) 💚1019
WO1020 steps158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚1
CRTTfirst chunk (pooled)101 (-4.7%)175 (+3.6%)372 (+84%) 🔻3550 (+770%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)115 (-20%)131 (-27%)168 (-42%)335 (-36%)96.5 (-32%)10
size sweep (100/s, 160B-12KB)127 (-9%)135 (-26%)172 (-32%)310 (-31%)134 (-14%)10
replay gateway-gpt-5.4-nano-2000t (1x)204 (+37%)139 (-4%)230 (+8%)675 (-3%)293 (+18%)3
replay eve-gpt-5.6-sol-2000t (1x)1837 (+1128%)140 (-5%)193 (±0%)3960 (+1082%)2212 (+683%)2
replay eve-gpt-5.6-sol-2000t (2x)372 (+120%)242 (+12%)468 (+23%)1195 (±0%)226 (-43%)3
ℹ️ Metric definitions & methodology
Streams: first-chunk RTT (the stream-open path, before any buffering/backpressure), CRTT percentiles, and worst delivery stall (CDV max). Cells are medians across iterations; per-run values in the artifacts. No 🔴/🟢 marks until targets attach.
The collapsed STSO distribution section above buckets every step gap, split inline (same warm process — pure framework overhead) vs queue-hop (fresh process — dispatch, reinit, replay). █ = main, ┃ = this run, ░ = fill.
The collapsed CRTT drill-down: per-variant RTT histograms (fixed log bins, · = empty) and mean RTT/positive-CDV profile lines over stream progress and chunk size. Histograms, avgs, and profiles merge exactly across runs; p50–p99 are percentile-of-percentiles. Per-index rows live in the artifacts.
Best/P75/P90/P99 deltas compare against the most recent benchmark run on main at the time of this run. 🔻 flags a delta worse than +15%, 💚 one better than −15%.
Metrics — TTFS: time to first step body (in-deployment start() → first step body) · Fan-out TTFS: fan-out time to first step (in-deployment start() → first of the parallel step bodies to complete) · Fan-out TTLS: fan-out time to last step (in-deployment start() → last of the parallel step bodies to complete, i.e. when the Promise.all resolves) · STSO: step-to-step overhead (gap between consecutive step bodies) · WO: workflow overhead (whole-run time outside step bodies, in-deployment anchored) · CRTT: chunk round-trip time (per-chunk write → read latency, one clock domain: deployment → stream backend → same deployment) · CDV: chunk delay variation / delivery jitter (inter-arrival gap minus inter-write gap per seq-adjacent pair; skew-free; the row is each run's MAX positive value, so one stall moves it)
Scenarios — step: one trivial no-op step, no stream; no hooks, so the run stays in turbo mode (in-process fast path) · stream: one streaming step; no hooks, so the run stays in turbo mode (in-process fast path) · hook + stream: registers a hook before one step, which exits turbo mode (dispatch path) · 1020 steps: 1020 trivial sequential steps; STSO is measured between consecutive steps in the given step ranges, and WO is the whole-run overhead outside step bodies · Promise.all(100 steps): 100 trivial no-op steps started together in a single Promise.all; Fan-out TTFS is the first of them to complete and Fan-out TTLS the last, both from the in-deployment clientStart, so their gap is the spread the runtime adds across the fan-out · paced control (100/s, 60B): the control: 300 tiny (~60B) deltas metronome-paced at 100/s — zero workload structure, so it reads the transport floor and flush cadence, and disambiguates transport-wide vs workload-specific when a replay row moves · size sweep (100/s, 160B-12KB): same pacing as the control with deltas padded in rotation across seven log-spaced sizes (~160B–12KB) — rotation decouples size from stream position, so it isolates whether chunk size causes latency · replay gateway-gpt-5.4-nano-2000t (1x): raw provider SSE cadence captured at the AI gateway boundary (gpt-5.4-nano, the most popular gateway model; per-token deltas p50 208B = the modal production chunk size), replayed exactly as measured — the typical customer's workload; its CDV is the typical customer's real delivery jitter · replay eve-gpt-5.6-sol-2000t (1x): a captured eve turn (gpt-5.6-sol, the most-used demanding eve model; ~2000 output tokens = production p50 turn length) replayed exactly as measured — eve's envelope protocol re-ships the cumulative message so sizes ramp 142B→13KB; the demanding outlier tenant's reality · replay eve-gpt-5.6-sol-2000t (2x): the same eve capture at 2x — the headroom/stress row; real fast-tier models emit the same chunk sizes at proportionally higher rate, so time compression is a faithful speed model · first chunk (pooled): every run's seq-0 RTT pooled across all stream scenarios — the first chunk precedes any workload differentiation, so pooling samples one shared stream-open path with exact percentiles
Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000teaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041
🔴 marks a percentile over its target (within target is left unmarked). Targets (p75/p90/p99, ms) — TTFS 200/300/600
All timestamps are deployment-side; runs are triggered in-deployment, so the CI runner and api.vercel.com sit outside every measured window. TTFS = start() → first step body (includes dispatch + any cold start); Fan-out TTFS/TTLS = first/last step completion of one Promise.all from the same anchor (the gap is the runtime’s fan-out spread); STSO/WO between step bodies; CRTT inside the workflow (excludes the api.vercel.com read path).
Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.
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Sim World
Simulated world deterministic testing for races. Traces
🟠 world-sim scenario book — 1 fail of 41 total
fence=per-spec
scenariooutcomeeventsvirtreplayviolations
✅ smoke-no-stepscompleted30msok0
✅ smoke-one-stepcompleted60msok0
✅ hook-at-step-startedcompleted120msok0
✅ hook-at-step-completedcompleted120msok0
✅ hook-at-hook-createdcompleted120msok0
✅ deadline-hook-winscompleted71.0hok0
✅ deadline-expirescompleted71.0hok0
✅ long-sleepcompleted1130.0dok0
✅ hook-never-arrivesstalled30msskipped0
✅ step-retries-twicecompleted102.0sok0
✅ parallel-stepscompleted90msok0
✅ hook-on-execution-statecompleted120msok0
✅ peek-hook-before-branchcompleted120msok0
✅ peek-hook-after-branchcompleted120msok0
✅ peek-hook-at-registrationcompleted120msok0
✅ race-hook-before-probecompleted120msok0
✅ race-hook-after-probecompleted120msok0
✅ race-duplicate-deliverycompleted130msok0
✅ attr-hook-before-stepcompleted110msok0
✅ attr-hook-after-stepcompleted110msok0
✅ attr-from-step-bodycompleted130msok0
✅ fork-hook-after-timeoutcompleted141.0mok0
✅ fork-hook-before-timeoutcompleted141.0mok0
✅ count-hook-after-timeoutcompleted171.0mok0
✅ count-hook-before-timeoutcompleted201.0mok0
✅ stale-read-step-count-forkcompleted201.0mok0
✅ stale-read-equal-step-countscompleted141.0mok0
✅ step-vs-step-forkcompleted120msok0
✅ step-vs-step-fork-fencedcompleted120msok0
✅ fence-catches-benign-directioncompleted125msok0
✅ in-flight-before-decisioncompleted171.0mok0
❌ in-flight-before-decision-countedcompleted171.0mok0
✅ in-flight-after-decisioncompleted192.0mok0
✅ stale-read-step-count-fork-fencedcompleted201.0mok0
✅ fork-hook-winscompleted131.0mok0
✅ fork-timeout-winscompleted131.0mok0
✅ unclaimed-payload-under-forkcompleted171.0mok0
✅ claimed-payload-under-forkcompleted171.0mok0
✅ writers-independent-step-bodiescompleted120msok0
✅ writers-scripted-tempocompleted120msok0
✅ cancel-mid-stepcancelled70msskipped0
Full trace: world-sim.txt
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peter/windows-step-registration-cleanup

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August 25, 2026 19:07
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No backport to stable for 5841558 (AI decision).
This is CI/test hardening for a failure mode that does not exist on stable: the generated __step_registrations.js that strands a deleted step fixture is main-only (on stable, step_registration appears only in the SWC plugin's Rust, and packages/next generates no such file), and the dev.test.ts changes build on main-only harness pieces (generatedStepRegistrationPath config, restoreDirectories). The tests.yml hunk likewise rewrites a Get-DevServerStatus pre-e2e probe block that stable does not have at all. Nothing here keeps stable buildable, testable, or releasable.
To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:
584155897f75e712a1c2bc199d6d12027cd18dab

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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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[core] Fail dev HMR cleanup on a stranded step registration - #3682
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[core] Fail dev HMR cleanup on a stranded step registration#3682
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Problem
Three of the last 120 Tests runs had E2E Windows Tests (node) burn its full ~30-minute

window and get cancelled with every e2e test failing on
[world-local] Queue message failed (HTTP 500), where the handlerError is a Next.js
_error page rather than anything workflow-shaped:
jobflow-route 500sstranded-import errors
9622825337310,13520,346
9621451553010,21810,886
9620285500910,28020,557
The flow route never answered a single request successfully in any of them. The dev server

log says why:
⨯ app/.well-known/workflow/v1/flow/__step_registrations.js:33:1
Module not found: Can't resolve '../../../../../workflows/source-map-warning-fixture.ts'

dev.test.ts > "should not log source map warnings for workflow node_modules imports"

writes workflows/source-map-warning-fixture.ts, which declares a 'use step' function,

and its afterEach deletes it. The generated __step_registrations.js imports every

discovered step file by path, so that deletion only stops breaking the flow route once a

rediscovery regenerates the file. When the watcher drops the unlink — which is what happens

on Windows — the generated file keeps importing a path that no longer exists, the flow route

stops compiling, and every workflow dispatch for the rest of the job gets a 500 pointing at

a fixture from a test that already passed.
The HMR log confirms nothing recovers it: 164 → 165 → 166 → 165 → 165 workflows, then

three skips and no further rediscovery. afterEach's prewarm() only waits for
workflow dev hmr: ready, printed once at startup, so nothing ever waited for the

post-deletion rediscovery in the first place.
The generated workflow bundle inlines workflow sources instead of importing them, so only
step-declaring fixtures can strand it. That is why new-workflow.ts leaks harmlessly in

the same runs while the source-map fixture is fatal.
The existing fail-fast guard cannot see this
The Windows job already probes the dev server before the long e2e run, precisely to avoid

burning the job window on a wedged server. It probes GET /api/chat, which compiles

independently of the flow route, so it reported -> 405 and let the suite run in all three

jobs.
Changes
  1. packages/core/e2e/dev.test.ts — after deleting fixtures, cleanup waits for the
    
generated step registrations to stop importing them. If they still do when the budget
    
runs out, the fixture contents are written back so the shared dev server keeps serving
    
the rest of the suite, and the hook fails naming the stranded file. CI already skips the
    
e2e suite when dev.test.ts fails, so this turns a 30-minute burn with ~10k misleading
    
500s into an immediate, accurate failure. The convergence wait runs before the
    node_modules fixture-package removal so a restored fixture still resolves its import.
  2. .github/workflows/tests.yml — the pre-e2e probe now POSTs
    /.well-known/workflow/v1/flow?__health, the SDK's own health endpoint on the route
    
that actually breaks. It returns 200 on a healthy dev server and would have returned 500
    
in all three jobs above.
Validation
Run locally against workbench/nextjs-turbopack on macOS (all 9 dev tests, so including

the flow-route HMR fuzz cases that also delete step-declaring files):
  • Happy path: the convergence wait never trips on any of the tests that delete fixtures. A
    
deletion converges in ~2s, so the watcher path itself is sound and the Windows miss is the
    
discriminator.
  • should follow Next flow-route HMR rebuild rules for body-only changes fails on macOS
    
(expected 2 to be 1 on an exact HMR log count). It fails identically with unmodified
    origin/main's dev.test.ts against the same dev server, so it is pre-existing and
    
unrelated. That case is skipped on Windows.
  • Forced-failure path (convergence budget shortened so it always expires): the hook fails
    
with the stranded path named, the fixture is restored, and
    POST /.well-known/workflow/v1/flow?__health still answers 200.
  • POST /.well-known/workflow/v1/flow?__health returns 200 on a healthy dev server and 500
    
when a path reachable from __step_registrations.js does not resolve, while
    GET /api/chat keeps answering 405 — the asymmetry the second change fixes.
The underlying Windows watcher miss is worth chasing separately; this PR stops it from

costing a whole job and makes it name itself.
Note on a related hole, not changed here
The Linux e2e-local-dev lane runs pnpm vitest run packages/core/e2e/dev.test.ts; sleep 10

and then continues into the full e2e suite, so a dev.test.ts failure there is discarded.

That lane would swallow the new hook failure too. Tightening it would newly red the lane on

pre-existing dev.test.ts flakes (the flow-route HMR fuzz case already fails on macOS

against unmodified main, see below), so it seemed worth raising separately rather than

bundling in.
@VaguelySerious@claude
[core] Fail dev HMR cleanup on a stranded step registration
62fcd0f
`dev.test.ts` fixtures that declare a `'use step'` function are imported by
path from the generated `__step_registrations.js`, so deleting one only stops
breaking the flow route once a rediscovery regenerates that file. When the dev
server's watcher drops the unlink, the generated file keeps importing a path
that no longer exists: the flow route stops compiling and every later workflow
dispatch in the job gets a 500 that names a fixture from a test that already
passed. Three of the last 120 `Tests` runs lost the whole ~30-minute Windows
e2e window this way, each with ~10k flow-route 500s and no successful dispatch.
Cleanup now waits for the generated step registrations to drop every file it
deleted. If they still reference one when the budget expires, the fixture is
written back so the shared dev server keeps serving the rest of the suite, and
the hook fails naming the stranded path. The wait runs before the node_modules
fixture-package removal so a restored fixture still resolves its import.
The pre-e2e probe moves from `GET /api/chat` to
`POST /.well-known/workflow/v1/flow?__health`. /api/chat compiles independently
of the flow route, so it answered 405 in all three jobs while every dispatch
was getting a 500.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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🦋 Changeset detected
Latest commit: d11c0dd
The changes in this PR will be included in the next version bump.
This PR includes changesets to release 16 packages
NameType
@workflow/corePatch
@workflow/buildersPatch
@workflow/cliPatch
@workflow/nextPatch
@workflow/nitroPatch
@workflow/vitestPatch
@workflow/web-sharedPatch
@workflow/webPatch
workflowPatch
@workflow/world-testingPatch
@workflow/astroPatch
@workflow/nestPatch
@workflow/rollupPatch
@workflow/sveltekitPatch
@workflow/vitePatch
@workflow/nuxtPatch
Not sure what this means? Click here to learn what changesets are.
Click here if you're a maintainer who wants to add another changeset to this PR
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The latest updates on your projects. Learn more about Vercel for GitHub.
ProjectDeploymentActionsUpdated (UTC)
example-nextjs-workflow-turbopackReadyReadyPreview, v0Aug 24, 2026 10:33pm
example-nextjs-workflow-webpackReadyReadyPreview, v0Aug 24, 2026 10:33pm
example-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-astro-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-express-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-fastify-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-hono-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-nestjs-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-nitro-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-nuxt-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-python-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-sveltekit-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-tanstack-start-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workbench-vite-workflowReadyReadyPreview, v0Aug 24, 2026 10:33pm
workflow-docsReadyReadyPreview, v0Aug 24, 2026 10:33pm
workflow-swc-playgroundReadyReadyPreview, v0Aug 24, 2026 10:33pm
workflow-tarballsReadyReadyPreview, v0Aug 24, 2026 10:33pm
workflow-webReadyReadyPreview, v0Aug 24, 2026 10:33pm
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🧪 E2E Test Results
❌ Some tests failed
❌ Failed E2E Tests
▲ Vercel Production (8 failed)
python-node (8 failed):
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9 | 🔍 observability
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K | 🔍 observability
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1 | 🔍 observability
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C | 🔍 observability
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C | 🔍 observability
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV | 🔍 observability
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG | 🔍 observability
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP | 🔍 observability
🌐 Cross-language Conformance (9 failed)
python (9 failed):
  • deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0TYP4EWXS4MHWKXFZN1JR0F
  • promiseAllWorkflow | wrun_41M0TYCQP90GH8HSRD6CPGTZZ9
  • sleepingWorkflow | wrun_41M0TYDCYJ0GJ31NQ8TEC2RM0K
  • parallelSleepWorkflow | wrun_41M0TYDG8X0GYYV0DPF5TTWPQ1
  • nullByteWorkflow | wrun_41M0TYDPF10GNAH5FBTG9D432C
  • cancelRun - cancelling a running workflow | wrun_41M0TYJFZ00GQDE241HGNYZ43C
  • cancelRun via CLI - cancelling a running workflow | wrun_41M0TYJKG60GR86KZH96M8F0ZV
  • sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0TYJV6W0GPABTHJT042EFNG
  • resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0TYKCQT0GK35M5THBBEEMBP
⚠️ Flaky E2E Tests (passed on retry)
These tests failed at least once and passed on a retry. A recurring entry here is a real race worth investigating.
  • addTenWorkflow (fastify)
  • addTenWorkflow (hono)
  • addTenWorkflow (nuxt)
  • cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
  • cancelRun via CLI - cancelling a running workflow (nuxt)
  • hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (nextjs-webpack)
  • hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (nextjs-webpack)
  • sleepWinsRaceWorkflow (tanstack-start)
🛠 Infra Events (absorbed by the harness)
Platform anomalies the e2e harness detected and worked around (e.g. a run the queue never picked up, replaced by a fresh run). Clustered timestamps indicate a backend blip; a steady drip indicates a platform issue worth escalating.
32 infra events
  • cold-start-warmup · suite warmup (python) · at 22:32:26Z · abandoned wrun_41M0TYAYJT0GNGCGFT9CW8J31C · (+7 more)
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN9
  • run-pickup-stall · nullByteWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKF10GW0JY2HGZZ2K8BR
  • run-pickup-stall · sleepingWorkflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKEX0GZ0RYFQZ1AGJAN8
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:32:42Z · abandoned wrun_41M0TYEKTR0GSK8P4JGC50Q9YT
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:32:43Z · abandoned wrun_41M0TYEKEQ0GVKJ0FPW7DV5X07
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:33:15Z · abandoned wrun_41M0TYFKB30GZV9RYEXPSVWC4S
  • run-pickup-stall · sleepingWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYP0GNT5G4RBTCFB13K
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF3N0GT1E7GFW1V9TJ21
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGEYS0GY7C05YYWCVAN24
  • run-pickup-stall · nullByteWorkflow (python) · at 22:33:43Z · abandoned wrun_41M0TYGF250GVD8T6M4BGNC9MZ
  • cold-start-warmup · suite warmup (tanstack-start) · at 22:34:07Z · abandoned wrun_01M0TYGV52206SC5AEK09QTHDV
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:34:33Z · abandoned wrun_41M0TYGK1Q0GP2X8Z95ZQRRF08
  • cold-start-warmup · suite warmup (python) · at 22:35:18Z · abandoned wrun_01M0TYG6112GWK343TTH7VNV7D · (+7 more)
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36E
  • run-pickup-stall · sleepingWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5VB4BEN37GS66N59YK
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5Y18NPGYQK6XKMNBJY
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:35:33Z · abandoned wrun_01M0TYKV5PD11HWJJ5DJPTY36D
  • run-pickup-stall · nullByteWorkflow (python) · at 22:35:33Z · abandoned wrun_01M0TYKV60YRZTH9DG0JNDANBH
  • run-pickup-stall · promiseAllWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSJYNGNK851MQP1JB09
  • run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSGB77J7W5E13A3R263
  • run-pickup-stall · sleepingWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSM1WW7VT6JAS9B0VEX
  • run-pickup-stall · parallelSleepWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSQ61EMZQSZ849JNHA7
  • run-pickup-stall · nullByteWorkflow (python) · at 22:36:33Z · abandoned wrun_01M0TYNNSR4ER537QZBJ79SN2G
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:36:55Z · abandoned wrun_41M0TYK6V80GQ8NYJDE1PPJBXH
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:36:55Z · abandoned wrun_41M0TYKAY70GYG61T79VHX87WA
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGD6NDH7M075CNB00CER
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDAM3PHNF2JA81T8P7Z
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:37:33Z · abandoned wrun_01M0TYQGDH2ZVXYM64QF0HSDRM
  • run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRQC396P9TA2NFEF1YW
  • run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 22:38:03Z · abandoned wrun_01M0TYRDRY07WYKZTT81X3CSEA
  • run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 22:38:33Z · abandoned wrun_01M0TYSB0M52SKJN6P09C9FJ4R
E2E Test Summary
Summary
PassedFailedSkippedTotal
❌ ▲ Vercel Production357087424320
✅ 💻 Local Development392205584480
✅ 📦 Local Production392205584480
✅ 🐘 Local Postgres392205584480
✅ 🪟 Windows32000320
❌ 🌐 Cross-language Conformance09132141
✅ vercel-http-transport8170143960
✅ vercel-multi-region270027
✅ vercel-ws-transport553087640
Total1705317277819848
Details by Category
❌ ▲ Vercel Production
AppPassedFailedSkipped
✅ astro-node132028
✅ astro-quickjs132028
✅ example-node132028
✅ example-quickjs132028
✅ express-node132028
✅ express-quickjs132028
✅ fastify-node132028
✅ fastify-quickjs132028
✅ hono-node132028
✅ hono-quickjs132028
✅ nest-node132028
✅ nest-quickjs132028
✅ nextjs-turbopack-node15703
✅ nextjs-turbopack-quickjs15703
✅ nextjs-webpack-node15703
✅ nextjs-webpack-quickjs15703
✅ nitro-node132028
✅ nitro-quickjs132028
✅ nuxt-node132028
✅ nuxt-quickjs132028
❌ python-node08152
✅ sveltekit-node15109
✅ sveltekit-quickjs15109
✅ tanstack-start-node132028
✅ tanstack-start-quickjs132028
✅ vite-node132028
✅ vite-quickjs132028
✅ 💻 Local Development
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 📦 Local Production
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🐘 Local Postgres
AppPassedFailedSkipped
✅ astro-stable-node134026
✅ astro-stable-quickjs134026
✅ express-stable-node134026
✅ express-stable-quickjs134026
✅ fastify-stable-node134026
✅ fastify-stable-quickjs134026
✅ hono-stable-node134026
✅ hono-stable-quickjs134026
✅ nest-stable-node134026
✅ nest-stable-quickjs134026
✅ nextjs-turbopack-canary-node141019
✅ nextjs-turbopack-canary-quickjs141019
✅ nextjs-turbopack-stable-node16000
✅ nextjs-turbopack-stable-quickjs16000
✅ nextjs-webpack-canary-node141019
✅ nextjs-webpack-canary-quickjs141019
✅ nextjs-webpack-stable-node16000
✅ nextjs-webpack-stable-quickjs16000
✅ nitro-stable-node134026
✅ nitro-stable-quickjs134026
✅ nuxt-stable-node134026
✅ nuxt-stable-quickjs134026
✅ sveltekit-stable-node15307
✅ sveltekit-stable-quickjs15307
✅ tanstack-start-node134026
✅ tanstack-start-quickjs134026
✅ vite-stable-node134026
✅ vite-stable-quickjs134026
✅ 🪟 Windows
AppPassedFailedSkipped
✅ nextjs-turbopack-node16000
✅ nextjs-turbopack-quickjs16000
❌ 🌐 Cross-language Conformance
AppPassedFailedSkipped
❌ python09132
✅ vercel-http-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ hono132028
✅ nextjs-turbopack15703
✅ nitro132028
✅ vite132028
✅ vercel-multi-region
AppPassedFailedSkipped
✅ nextjs-turbopack2700
✅ vercel-ws-transport
AppPassedFailedSkipped
✅ example132028
✅ express132028
✅ nextjs-turbopack15703
✅ vite132028
📋 View full workflow run
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📊 Workflow Benchmarks
commit d11c0dd · Mon, 24 Aug 2026 22:55:03 GMT · run logs
Backend: vercel · app: nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep246 (-75%) 💚1346 🔴 (+22%) 🔻1384 🔴 (+20%) 🔻1484 🔴 (+18%) 🔻30
TTFSstream222 (-69%) 💚1328 🔴 (+21%) 🔻1400 🔴 (+26%) 🔻1432 🔴 (+11%)30
TTFShook + stream1264 (-8.0%)1646 🔴 (+12%)1722 🔴 (+14%)2321 🔴 (+45%) 🔻30
Fan-out TTFSPromise.all(100 steps)645 (-0.8%)1882 (+10%)2135 (+19%) 🔻2343 (+20%) 🔻10
Fan-out TTLSPromise.all(100 steps)1841 (-4.7%)3816 (+20%) 🔻5084 (+55%) 🔻5570 (-34%) 💚10
STSO1020 steps (inline)69 (-34%) 💚140 (-5.4%)164 (-2.4%)275 (+26%) 🔻1019
WO1020 steps140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)140686 (-4.7%)1
CRTTfirst chunk (pooled)107 (+22%) 🔻171 (+38%) 🔻260 (+35%) 🔻274 (-56%) 💚28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+25%)256 (+97%)513 (+142%)967 (+27%)279 (+95%)10
size sweep (100/s, 160B-12KB)150 (+33%)164 (+15%)275 (+47%)495 (-56%)195 (+42%)10
replay gateway-gpt-5.4-nano-2000t (1x)131 (+7%)532 (-18%)706 (-79%)911 (-81%)203 (-6%)3
replay eve-gpt-5.6-sol-2000t (1x)216 (+83%)168 (+25%)261 (+54%)1122 (+225%)761 (+191%)2
replay eve-gpt-5.6-sol-2000t (2x)150 (+22%)207 (+13%)274 (+4%)691 (+25%)268 (+18%)3
📈 STSO distribution vs main (inline / queue-hop histograms)
1020 steps (inline)
Cumulative STSO time: main 147417ms → this run 140462ms (Δ -6955ms, -5%)
 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████░┃ main 785 this 848 +63
150-200 ms ███┃██ main 216 this 143 -73
200-250 ms ┃ main 14 this 11 -3
250-300 ms ┃ main 4 this 9 +5
300-350 ms ┃ main 0 this 5 +5
350-400 ms ┃ main 0 this 1 +1
400-450 ms ┃ main 0 this 1 +1

📈 CRTT drill-down vs main (RTT distributions & profiles)
variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▃█▃▁··· 175.1 (+46%) 135 (+27%) 513 (+142%) 967 (+27%) 3000
sweep ······▃█▂▁··· 136.8 (+11%) 122 (+11%) 275 (+47%) 495 (-56%) 3000
gw 1x ·····▁▄█▃▂··· 203.3 (-39%) 119 (+18%) 706 (-79%) 911 (-81%) 5295
eve 1x ·····▁▃█▂▁▁·· 171.8 (+55%) 129 (+42%) 261 (+54%) 1122 (+225%) 5186
eve 2x ·····▁▂█▃▁··· 167.7 (+20%) 149 (+16%) 274 (+4%) 691 (+25%) 7779

RTT over stream progress (avg per tenth of stream, bars scaled min→max):
control ▅█▄▆▃▄▁▆▅█ 145–199ms
sweep █▆▂▁▂▅▃▁▃▂ 116–178ms
gw 1x ██▄▄▅▁▂▄▇▅ 122–275ms
eve 1x ▂▂▃▂▁▁▄█▁▁ 121–326ms
eve 2x ▃▁▁▁▁▂▅██▂ 142–224ms

RTT by chunk size (avg per log size bin, ~160B → ~12KB serialized, bars scaled min→max):
sweep ▁▅█▅▅▂▃ 136–138ms

Delivery jitter over stream progress (avg positive CDV per tenth of stream, bars scaled min→max):
control ▄▁▁▆▆▃▆▄█▅ 34–56ms
sweep ▁▃▃▃▆▄▆▄█▂ 44–59ms
gw 1x █▄▂▂▃▁▄▃▆▃ 38–71ms
eve 1x ▅▆▆▅▃▁█▅▃▃ 24–39ms
eve 2x █▇▁▃▆▅█▃▄▆ 22–36ms

📜 Previous results (2)
47501c6
Fri, 21 Aug 2026 23:12:41 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1314 (+22%) 🔻1396 🔴 (+21%) 🔻1428 🔴 (+14%)1481 🔴 (+3.6%)30
TTFSstream270 (-75%) 💚1352 🔴 (+12%)1378 🔴 (+7.1%)1389 🔴 (-3.9%)30
TTFShook + stream1534 (+45%) 🔻1659 🔴 (+14%)1766 🔴 (+17%) 🔻2433 🔴 (+57%) 🔻30
Fan-out TTFSPromise.all(100 steps)568 (-4.1%)2033 (+28%) 🔻2052 (+24%) 🔻2111 (+27%) 🔻10
Fan-out TTLSPromise.all(100 steps)1699 (+5.1%)3860 (+28%) 🔻4036 (+12%)4573 (+16%) 🔻10
STSO1020 steps (inline)114 (-24%) 💚168 (-24%) 💚189 (-27%) 💚344 (-36%) 💚1019
WO1020 steps169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚169326 (-22%) 💚1
CRTTfirst chunk (pooled)99 (+4.2%)152 (+2.7%)189 (+8.6%)376 (+62%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)141 (+9%)143 (-23%)186 (-27%)402 (+6%)110 (-35%)10
size sweep (100/s, 160B-12KB)125 (+1%)151 (-18%)195 (-42%)279 (-46%)99.5 (-25%)10
replay gateway-gpt-5.4-nano-2000t (1x)152 (+26%)189 (-74%)414 (-87%)757 (-84%)466 (-86%)3
replay eve-gpt-5.6-sol-2000t (1x)159 (+31%)148 (-8%)186 (-10%)287 (-20%)296 (-2%)2
replay eve-gpt-5.6-sol-2000t (2x)135 (-13%)200 (-38%)268 (-73%)380 (-83%)246 (-38%)3
62fcd0f
Wed, 19 Aug 2026 23:10:40 GMT · run logs
vercel / nextjs-turbopack
MetricScenarioBest (ms)P75 (ms)P90 (ms)P99 (ms)Samples
TTFSstep1287 (+24%) 🔻1401 🔴 (+19%) 🔻1442 🔴 (+17%) 🔻1732 🔴 (+4.1%)30
TTFSstream1260 (+25%) 🔻1388 🔴 (+25%) 🔻1428 🔴 (+25%) 🔻1742 🔴 (+49%) 🔻30
TTFShook + stream538 (-58%) 💚1644 🔴 (+15%)1690 🔴 (+15%)1986 🔴 (+26%) 🔻30
Fan-out TTFSPromise.all(100 steps)527 (-7.9%)829 (-16%) 💚986 (-45%) 💚2498 (+38%) 🔻10
Fan-out TTLSPromise.all(100 steps)4804 (+1.2%)8742 (+6.0%)9471 (-13%)10733 (-19%) 💚10
STSO1020 steps (inline)117 (-5.6%)159 (-35%) 💚185 (-37%) 💚303 (-40%) 💚1019
WO1020 steps158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚158021 (-33%) 💚1
CRTTfirst chunk (pooled)101 (-4.7%)175 (+3.6%)372 (+84%) 🔻3550 (+770%) 🔻28
Streams
ScenarioCRTT 1stp75p90p99CDV maxiters
paced control (100/s, 60B)115 (-20%)131 (-27%)168 (-42%)335 (-36%)96.5 (-32%)10
size sweep (100/s, 160B-12KB)127 (-9%)135 (-26%)172 (-32%)310 (-31%)134 (-14%)10
replay gateway-gpt-5.4-nano-2000t (1x)204 (+37%)139 (-4%)230 (+8%)675 (-3%)293 (+18%)3
replay eve-gpt-5.6-sol-2000t (1x)1837 (+1128%)140 (-5%)193 (±0%)3960 (+1082%)2212 (+683%)2
replay eve-gpt-5.6-sol-2000t (2x)372 (+120%)242 (+12%)468 (+23%)1195 (±0%)226 (-43%)3
ℹ️ Metric definitions & methodology
Streams: first-chunk RTT (the stream-open path, before any buffering/backpressure), CRTT percentiles, and worst delivery stall (CDV max). Cells are medians across iterations; per-run values in the artifacts. No 🔴/🟢 marks until targets attach.
The collapsed STSO distribution section above buckets every step gap, split inline (same warm process — pure framework overhead) vs queue-hop (fresh process — dispatch, reinit, replay). █ = main, ┃ = this run, ░ = fill.
The collapsed CRTT drill-down: per-variant RTT histograms (fixed log bins, · = empty) and mean RTT/positive-CDV profile lines over stream progress and chunk size. Histograms, avgs, and profiles merge exactly across runs; p50–p99 are percentile-of-percentiles. Per-index rows live in the artifacts.
Best/P75/P90/P99 deltas compare against the most recent benchmark run on main at the time of this run. 🔻 flags a delta worse than +15%, 💚 one better than −15%.
Metrics — TTFS: time to first step body (in-deployment start() → first step body) · Fan-out TTFS: fan-out time to first step (in-deployment start() → first of the parallel step bodies to complete) · Fan-out TTLS: fan-out time to last step (in-deployment start() → last of the parallel step bodies to complete, i.e. when the Promise.all resolves) · STSO: step-to-step overhead (gap between consecutive step bodies) · WO: workflow overhead (whole-run time outside step bodies, in-deployment anchored) · CRTT: chunk round-trip time (per-chunk write → read latency, one clock domain: deployment → stream backend → same deployment) · CDV: chunk delay variation / delivery jitter (inter-arrival gap minus inter-write gap per seq-adjacent pair; skew-free; the row is each run's MAX positive value, so one stall moves it)
Scenarios — step: one trivial no-op step, no stream; no hooks, so the run stays in turbo mode (in-process fast path) · stream: one streaming step; no hooks, so the run stays in turbo mode (in-process fast path) · hook + stream: registers a hook before one step, which exits turbo mode (dispatch path) · 1020 steps: 1020 trivial sequential steps; STSO is measured between consecutive steps in the given step ranges, and WO is the whole-run overhead outside step bodies · Promise.all(100 steps): 100 trivial no-op steps started together in a single Promise.all; Fan-out TTFS is the first of them to complete and Fan-out TTLS the last, both from the in-deployment clientStart, so their gap is the spread the runtime adds across the fan-out · paced control (100/s, 60B): the control: 300 tiny (~60B) deltas metronome-paced at 100/s — zero workload structure, so it reads the transport floor and flush cadence, and disambiguates transport-wide vs workload-specific when a replay row moves · size sweep (100/s, 160B-12KB): same pacing as the control with deltas padded in rotation across seven log-spaced sizes (~160B–12KB) — rotation decouples size from stream position, so it isolates whether chunk size causes latency · replay gateway-gpt-5.4-nano-2000t (1x): raw provider SSE cadence captured at the AI gateway boundary (gpt-5.4-nano, the most popular gateway model; per-token deltas p50 208B = the modal production chunk size), replayed exactly as measured — the typical customer's workload; its CDV is the typical customer's real delivery jitter · replay eve-gpt-5.6-sol-2000t (1x): a captured eve turn (gpt-5.6-sol, the most-used demanding eve model; ~2000 output tokens = production p50 turn length) replayed exactly as measured — eve's envelope protocol re-ships the cumulative message so sizes ramp 142B→13KB; the demanding outlier tenant's reality · replay eve-gpt-5.6-sol-2000t (2x): the same eve capture at 2x — the headroom/stress row; real fast-tier models emit the same chunk sizes at proportionally higher rate, so time compression is a faithful speed model · first chunk (pooled): every run's seq-0 RTT pooled across all stream scenarios — the first chunk precedes any workload differentiation, so pooling samples one shared stream-open path with exact percentiles
Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000teaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041
🔴 marks a percentile over its target (within target is left unmarked). Targets (p75/p90/p99, ms) — TTFS 200/300/600
All timestamps are deployment-side; runs are triggered in-deployment, so the CI runner and api.vercel.com sit outside every measured window. TTFS = start() → first step body (includes dispatch + any cold start); Fan-out TTFS/TTLS = first/last step completion of one Promise.all from the same anchor (the gap is the runtime’s fan-out spread); STSO/WO between step bodies; CRTT inside the workflow (excludes the api.vercel.com read path).
Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.
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Sim World
Simulated world deterministic testing for races. Traces
🟠 world-sim scenario book — 1 fail of 41 total
fence=per-spec
scenariooutcomeeventsvirtreplayviolations
✅ smoke-no-stepscompleted30msok0
✅ smoke-one-stepcompleted60msok0
✅ hook-at-step-startedcompleted120msok0
✅ hook-at-step-completedcompleted120msok0
✅ hook-at-hook-createdcompleted120msok0
✅ deadline-hook-winscompleted71.0hok0
✅ deadline-expirescompleted71.0hok0
✅ long-sleepcompleted1130.0dok0
✅ hook-never-arrivesstalled30msskipped0
✅ step-retries-twicecompleted102.0sok0
✅ parallel-stepscompleted90msok0
✅ hook-on-execution-statecompleted120msok0
✅ peek-hook-before-branchcompleted120msok0
✅ peek-hook-after-branchcompleted120msok0
✅ peek-hook-at-registrationcompleted120msok0
✅ race-hook-before-probecompleted120msok0
✅ race-hook-after-probecompleted120msok0
✅ race-duplicate-deliverycompleted130msok0
✅ attr-hook-before-stepcompleted110msok0
✅ attr-hook-after-stepcompleted110msok0
✅ attr-from-step-bodycompleted130msok0
✅ fork-hook-after-timeoutcompleted141.0mok0
✅ fork-hook-before-timeoutcompleted141.0mok0
✅ count-hook-after-timeoutcompleted171.0mok0
✅ count-hook-before-timeoutcompleted201.0mok0
✅ stale-read-step-count-forkcompleted201.0mok0
✅ stale-read-equal-step-countscompleted141.0mok0
✅ step-vs-step-forkcompleted120msok0
✅ step-vs-step-fork-fencedcompleted120msok0
✅ fence-catches-benign-directioncompleted125msok0
✅ in-flight-before-decisioncompleted171.0mok0
❌ in-flight-before-decision-countedcompleted171.0mok0
✅ in-flight-after-decisioncompleted192.0mok0
✅ stale-read-step-count-fork-fencedcompleted201.0mok0
✅ fork-hook-winscompleted131.0mok0
✅ fork-timeout-winscompleted131.0mok0
✅ unclaimed-payload-under-forkcompleted171.0mok0
✅ claimed-payload-under-forkcompleted171.0mok0
✅ writers-independent-step-bodiescompleted120msok0
✅ writers-scripted-tempocompleted120msok0
✅ cancel-mid-stepcancelled70msskipped0
Full trace: world-sim.txt
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August 21, 2026 22:48
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merged commit 5841558
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deleted the

peter/windows-step-registration-cleanup

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August 25, 2026 19:07
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No backport to stable for 5841558 (AI decision).
This is CI/test hardening for a failure mode that does not exist on stable: the generated __step_registrations.js that strands a deleted step fixture is main-only (on stable, step_registration appears only in the SWC plugin's Rust, and packages/next generates no such file), and the dev.test.ts changes build on main-only harness pieces (generatedStepRegistrationPath config, restoreDirectories). The tests.yml hunk likewise rewrites a Get-DevServerStatus pre-e2e probe block that stable does not have at all. Nothing here keeps stable buildable, testable, or releasable.
To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:
584155897f75e712a1c2bc199d6d12027cd18dab

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