fix(world-local): abort deliveries on shutdown

[AndrewBarba]

Description

world-local creates a shutdown AbortController, but the controller was only connected to delivery delays and retry backoffs. An HTTP delivery with disabled transport timeouts therefore remained active when the World closed, and undici's graceful Agent.close() waited indefinitely for that request to finish.

Pass the existing close signal to both HTTP transports. Closing the World now aborts its active delivery requests before releasing the transport pool, while preserving graceful agent cleanup and the durable message for recovery after restart.

This was exposed by vercel/eve#2609, which disables local delivery timeouts to prevent healthy long-running agent turns from being redelivered.

How did you test your changes?

Added a world-local queue regression test with both transport timeouts disabled and a server that accepts but never completes the delivery. The test reports timed-out on main and closes immediately with this change.

• pnpm exec turbo build --filter=@workflow/world-local...
• pnpm --filter @workflow/world-local exec vitest run src/queue.test.ts — 26 passed
• pnpm --filter @workflow/world-local typecheck
• pnpm exec biome check packages/world-local/src/queue.ts packages/world-local/src/queue.test.ts — passed with the two existing complexity warnings

PR Checklist - Required to merge

• 📦 pnpm changeset was run to create a changelog for this PR
• 🔒 DCO sign-off passes (run git commit --signoff on your commits)
• 📝 Ping @vercel/workflow in a comment once the PR is ready, and the above checklist is complete

[AndrewBarba]

@vercel/workflow ready for review.

[changeset-bot]

🦋 Changeset detected

Latest commit: db061c6

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

This PR includes changesets to release 18 packages

Name	Type
@workflow/world-local	Patch
@workflow/cli	Patch
@workflow/core	Patch
@workflow/vitest	Patch
@workflow/web	Patch
@workflow/world-postgres	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/web-shared	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

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

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-nextjs-workflow-webpack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-astro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-express-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-fastify-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-hono-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nestjs-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nitro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nuxt-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-python-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-sveltekit-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-tanstack-start-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-vite-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-docs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-swc-playground	Building	Preview, v0	Aug 26, 2026 8:36pm
workflow-tarballs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-web	Ready	Preview, v0	Aug 26, 2026 8:36pm

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

▲ Vercel Production (8 failed)

python-node (8 failed):

• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S | 🔍 observability
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ | 🔍 observability
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG | 🔍 observability
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE | 🔍 observability
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z | 🔍 observability
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT | 🔍 observability
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW | 🔍 observability
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE | 🔍 observability

🌐 Cross-language Conformance (9 failed)

python (9 failed):

• deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0ZWXYSJK22VDCG6YRXP6Q4B
• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE

vercel-multi-region (1 failed)

nextjs-turbopack (1 failed):

• multi-region (world-vercel) hooks on non-iad1 runs hook created by a sfo1 run resolves by token and resumes the run

⚠️ 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.

• deploymentId: 'latest' is a no-op in non-Vercel worlds (nitro)
• hookWithSleepFinalStepWorkflow - step only on final payload (nextjs-webpack)
• hookWorkflow (vite)
• 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.

34 infra events

• cold-start-warmup · suite warmup (python) · at 20:37:39Z · abandoned wrun_41M0ZWJ7WC0GM60ZYBBV2EBQD7 · (+7 more)
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1214
• run-pickup-stall · sleepingWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1213
• run-pickup-stall · nullByteWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH80GVRAN0AWJ7YQ6MY
• run-pickup-stall · promiseAllWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWGY0GJMHCXMPNX6S92S
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWSR0GP3W2DTFB1K69G6
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:38:28Z · abandoned wrun_41M0ZWPVWH0GHX1S11MM5REDP6
• run-pickup-stall · sleepingWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRH0GWH567ZD71WNDMP
• run-pickup-stall · nullByteWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRV0GYJ9PNYHYS89384
• run-pickup-stall · promiseAllWorkflow (python) · at 20:38:57Z · abandoned wrun_41M0ZWQR210GYB5TX06QESX365
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQRH80GJW6FHAQ8V97R9Y
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQV270GWF3V8QH1A8TWMJ
• cold-start-warmup · suite warmup (tanstack-start) · at 20:39:32Z · abandoned wrun_01M0ZWRFCR447TPW9VBW47CCSW
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:40:39Z · abandoned wrun_41M0ZWSRM40GTN4NF0CM5BMN4Z
• cold-start-warmup · suite warmup (python) · at 20:40:49Z · abandoned wrun_01M0ZWR0BZGWCSF0604B0QCS6V · (+7 more)
• run-pickup-stall · sleepingWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH26HN0J7P54QFWRCBT
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGXC6S647VGAZRBBDM9
• run-pickup-stall · nullByteWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH4WVZDC8P1N4TTD1M0
• run-pickup-stall · promiseAllWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGYQHTPNF5W7QPC4MRT
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH3465Q0K3EF487NGED
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:41:18Z · abandoned wrun_41M0ZWSWDZ0GQJ7Q4JYSDDHBTC
• run-pickup-stall · promiseAllWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4EWN54KW4THDWD7T8P
• run-pickup-stall · sleepingWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4HPPDBEHP4NVYFDGN5
• run-pickup-stall · nullByteWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4PCAYE9B8P00J4SCJM
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4BX3YXM3R76WC7CEBX
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4JHHTBRP5FD3DY6392
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQRX9WM6Z4GWW3WJP2D
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQY8R1SKMNWJ5YA9TVE
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQZ8VVKD8GBGM62NTDW
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0838BE3N4FNY4W5KSPK6
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0836388GCBWB0RZF60FW
• run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (nextjs-webpack) · at 20:43:55Z · abandoned wrun_01M0ZX0WB1WDKJYXCQT7X2M0B3
• run-pickup-stall · concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (nextjs-webpack) · at 20:44:00Z · abandoned wrun_01M0ZX11CSS1MAQFSQMF187QW0
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:44:04Z · abandoned wrun_01M0ZX15B28M5P8J1N1VPYADWG

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
❌ ▲ Vercel Production	3570	8	742	4320
✅ 💻 Local Development	3922	0	558	4480
✅ 📦 Local Production	3922	0	558	4480
✅ 🐘 Local Postgres	3922	0	558	4480
✅ 🪟 Windows	320	0	0	320
❌ 🌐 Cross-language Conformance	0	9	132	141
✅ vercel-http-transport	817	0	143	960
❌ vercel-multi-region	26	1	0	27
✅ vercel-ws-transport	553	0	87	640
Total	17052	18	2778	19848

Details by Category

❌ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	132	0	28
✅ astro-quickjs	132	0	28
✅ example-node	132	0	28
✅ example-quickjs	132	0	28
✅ express-node	132	0	28
✅ express-quickjs	132	0	28
✅ fastify-node	132	0	28
✅ fastify-quickjs	132	0	28
✅ hono-node	132	0	28
✅ hono-quickjs	132	0	28
✅ nest-node	132	0	28
✅ nest-quickjs	132	0	28
✅ nextjs-turbopack-node	157	0	3
✅ nextjs-turbopack-quickjs	157	0	3
✅ nextjs-webpack-node	157	0	3
✅ nextjs-webpack-quickjs	157	0	3
✅ nitro-node	132	0	28
✅ nitro-quickjs	132	0	28
✅ nuxt-node	132	0	28
✅ nuxt-quickjs	132	0	28
❌ python-node	0	8	152
✅ sveltekit-node	151	0	9
✅ sveltekit-quickjs	151	0	9
✅ tanstack-start-node	132	0	28
✅ tanstack-start-quickjs	132	0	28
✅ vite-node	132	0	28
✅ vite-quickjs	132	0	28

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	160	0	0
✅ nextjs-turbopack-quickjs	160	0	0

❌ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
❌ python	0	9	132

✅ vercel-http-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ hono	132	0	28
✅ nextjs-turbopack	157	0	3
✅ nitro	132	0	28
✅ vite	132	0	28

❌ vercel-multi-region

App	Passed	Failed	Skipped
❌ nextjs-turbopack	26	1	0

✅ vercel-ws-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ nextjs-turbopack	157	0	3
✅ vite	132	0	28

---

📋 View full workflow run

[github-actions]

📊 Workflow Benchmarks

commit db061c6 · Wed, 26 Aug 2026 21:00:08 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1329 (+39%) 🔻	1506 🔴 (+42%) 🔻	1575 🔴 (+43%) 🔻	1643 🔴 (+40%) 🔻	30
TTFS	stream	1061 (+539%) 🔻	1376 🔴 (+30%) 🔻	1420 🔴 (+25%) 🔻	1651 🔴 (+37%) 🔻	30
TTFS	hook + stream	493 (-61%) 💚	1633 🔴 (+22%) 🔻	1659 🔴 (+22%) 🔻	1707 🔴 (-24%) 💚	30
Fan-out TTFS	Promise.all(100 steps)	606 (+30%) 🔻	968 (+30%) 🔻	989 (-42%) 💚	2274 (-50%) 💚	10
Fan-out TTLS	Promise.all(100 steps)	2043 (+12%)	5113 (+23%) 🔻	5536 (+12%)	9647 (-2.8%)	10
STSO	1020 steps (inline)	89 (-14%)	135 (+5.5%)	160 (+8.1%)	217 (-26%) 💚	1019
WO	1020 steps	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	1
CRTT	first chunk (pooled)	110 (+41%) 🔻	148 (+11%)	189 (+12%)	270 (-18%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	125 (+21%)	167 (+31%)	213 (+17%)	312 (-21%)	123 (-24%)	10
size sweep (100/s, 160B-12KB)	132 (+25%)	174 (+7%)	236 (-50%)	356 (-60%)	155 (-32%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	135 (-20%)	1102 (+748%)	3758 (+2206%)	5151 (+787%)	362 (-15%)	3
replay eve-gpt-5.6-sol-2000t (1x)	136 (-1%)	151 (+11%)	199 (+11%)	321 (-59%)	255 (-60%)	2
replay eve-gpt-5.6-sol-2000t (2x)	171 (+29%)	194 (-2%)	377 (+17%)	931 (+63%)	301 (+11%)	3

📈 STSO distribution vs main (inline / queue-hop histograms)

1020 steps (inline)

Cumulative STSO time: main 134890ms → this run 136346ms (Δ +1456ms, +1%)

 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████┃█ main 924 this 869 -55
150-200 ms ██┃ main 76 this 133 +57
200-250 ms ┃ main 4 this 8 +4
250-300 ms ┃ main 5 this 3 -2
300-350 ms ┃ main 1 this 5 +4
350-400 ms ┃ main 1 this 0 -1
650-700 ms ┃ main 1 this 0 -1
700-750 ms ┃ main 2 this 0 -2
750-800 ms ┃ main 1 this 0 -1
800-850 ms ┃ main 2 this 0 -2
1150-1200 ms ┃ main 1 this 0 -1
1200-1250 ms ┃ main 1 this 0 -1

📈 CRTT drill-down vs main (RTT distributions & profiles)

variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▂█▁···· 133.7 (+23%) 124 (+27%) 213 (+17%) 312 (-21%) 3000
sweep ······▂█▂···· 140.1 (-4%) 127 (+25%) 236 (-50%) 356 (-60%) 3000
gw 1x ·····▁▃█▁▁▁▁▁ 397.7 (+245%) 118 (+16%) 3758 (+2206%) 5151 (+787%) 5295
eve 1x ·····▁▄█▁···· 127 (+5%) 118 (+26%) 199 (+11%) 321 (-59%) 5186
eve 2x ·····▁▂█▃▁··· 173.6 (+11%) 145 (+12%) 377 (+17%) 931 (+63%) 7779

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

control █▂▆▃▁▁▃▅▂▅ 125–148ms
sweep ▆▆█▅▆▂▁▅▆▆ 122–153ms
gw 1x ▁▁▁▁▁█▅▂▁▁ 115–1601ms
eve 1x ▂▂▅▅▁▄▇█▄▆ 114–141ms
eve 2x ▁▁▂▁▁▁▂█▃▁ 129–382ms

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

sweep ▃▆█▃▂▂▁ 139–142ms

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

control ▁▇▂▃▅▅▄▁▄█ 33–44ms
sweep ▁▂█▅▆▅▅▆▅▄ 40–56ms
gw 1x ▁▂▂▁█▄▁▂▂▂ 33–80ms
eve 1x ▁▃▁▃▂▄▆▃█▅ 22–27ms
eve 2x ▆▂▂▃▄▁▁▂█▄ 23–31ms

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.}

[github-actions]

Sim World

Simulated world deterministic testing for races. Traces

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

fence=per-spec

scenario	outcome	events	virt	replay	violations
✅ smoke-no-steps	completed	3	0ms	ok	0
✅ smoke-one-step	completed	6	0ms	ok	0
✅ hook-at-step-started	completed	12	0ms	ok	0
✅ hook-at-step-completed	completed	12	0ms	ok	0
✅ hook-at-hook-created	completed	12	0ms	ok	0
✅ deadline-hook-wins	completed	7	1.0h	ok	0
✅ deadline-expires	completed	7	1.0h	ok	0
✅ long-sleep	completed	11	30.0d	ok	0
✅ hook-never-arrives	stalled	3	0ms	skipped	0
✅ step-retries-twice	completed	10	2.0s	ok	0
✅ parallel-steps	completed	9	0ms	ok	0
✅ hook-on-execution-state	completed	12	0ms	ok	0
✅ peek-hook-before-branch	completed	12	0ms	ok	0
✅ peek-hook-after-branch	completed	12	0ms	ok	0
✅ peek-hook-at-registration	completed	12	0ms	ok	0
✅ race-hook-before-probe	completed	12	0ms	ok	0
✅ race-hook-after-probe	completed	12	0ms	ok	0
✅ race-duplicate-delivery	completed	13	0ms	ok	0
✅ attr-hook-before-step	completed	11	0ms	ok	0
✅ attr-hook-after-step	completed	11	0ms	ok	0
✅ attr-from-step-body	completed	13	0ms	ok	0
✅ fork-hook-after-timeout	completed	14	1.0m	ok	0
✅ fork-hook-before-timeout	completed	14	1.0m	ok	0
✅ count-hook-after-timeout	completed	17	1.0m	ok	0
✅ count-hook-before-timeout	completed	20	1.0m	ok	0
✅ stale-read-step-count-fork	completed	20	1.0m	ok	0
✅ stale-read-equal-step-counts	completed	14	1.0m	ok	0
✅ step-vs-step-fork	completed	12	0ms	ok	0
✅ step-vs-step-fork-fenced	completed	12	0ms	ok	0
✅ fence-catches-benign-direction	completed	12	5ms	ok	0
✅ in-flight-before-decision	completed	17	1.0m	ok	0
❌ in-flight-before-decision-counted	completed	17	1.0m	ok	0
✅ in-flight-after-decision	completed	19	2.0m	ok	0
✅ stale-read-step-count-fork-fenced	completed	20	1.0m	ok	0
✅ fork-hook-wins	completed	13	1.0m	ok	0
✅ fork-timeout-wins	completed	13	1.0m	ok	0
✅ unclaimed-payload-under-fork	completed	17	1.0m	ok	0
✅ claimed-payload-under-fork	completed	17	1.0m	ok	0
✅ writers-independent-step-bodies	completed	12	0ms	ok	0
✅ writers-scripted-tempo	completed	12	0ms	ok	0
✅ cancel-mid-step	cancelled	7	0ms	skipped	0

Full trace: world-sim.txt

[github-actions]

Framework	Flow route	Step reg.	Framework output
hono	200.9 KiB (±0)	40.3 KiB (±0)	1.76 MiB (+7 B)
nextjs-turbopack	206.3 KiB (±0)	439 B (±0)	763.1 KiB (+7 B)

About these numbers

Sizes are gzip; parentheses show the change against main.
Flow route and Step reg. gate this job, on raw bytes rather than the gzip shown, at max(2%, 50.0 KiB). Framework output is informational.

db061c6 · run

[github-actions]

Backport PR opened against stable: #3827. Merge conflicts were resolved by AI — please review carefully. (backport job run)

[AndrewBarba]

Description

world-local creates a shutdown AbortController, but the controller was only connected to delivery delays and retry backoffs. An HTTP delivery with disabled transport timeouts therefore remained active when the World closed, and undici's graceful Agent.close() waited indefinitely for that request to finish.

Pass the existing close signal to both HTTP transports. Closing the World now aborts its active delivery requests before releasing the transport pool, while preserving graceful agent cleanup and the durable message for recovery after restart.

This was exposed by vercel/eve#2609, which disables local delivery timeouts to prevent healthy long-running agent turns from being redelivered.

How did you test your changes?

Added a world-local queue regression test with both transport timeouts disabled and a server that accepts but never completes the delivery. The test reports timed-out on main and closes immediately with this change.

• pnpm exec turbo build --filter=@workflow/world-local...
• pnpm --filter @workflow/world-local exec vitest run src/queue.test.ts — 26 passed
• pnpm --filter @workflow/world-local typecheck
• pnpm exec biome check packages/world-local/src/queue.ts packages/world-local/src/queue.test.ts — passed with the two existing complexity warnings

PR Checklist - Required to merge

• 📦 pnpm changeset was run to create a changelog for this PR
• 🔒 DCO sign-off passes (run git commit --signoff on your commits)
• 📝 Ping @vercel/workflow in a comment once the PR is ready, and the above checklist is complete

[AndrewBarba]

@vercel/workflow ready for review.

[changeset-bot]

🦋 Changeset detected

Latest commit: db061c6

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

This PR includes changesets to release 18 packages

Name	Type
@workflow/world-local	Patch
@workflow/cli	Patch
@workflow/core	Patch
@workflow/vitest	Patch
@workflow/web	Patch
@workflow/world-postgres	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/web-shared	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

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

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-nextjs-workflow-webpack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-astro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-express-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-fastify-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-hono-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nestjs-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nitro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nuxt-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-python-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-sveltekit-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-tanstack-start-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-vite-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-docs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-swc-playground	Building	Preview, v0	Aug 26, 2026 8:36pm
workflow-tarballs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-web	Ready	Preview, v0	Aug 26, 2026 8:36pm

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

▲ Vercel Production (8 failed)

python-node (8 failed):

• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S | 🔍 observability
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ | 🔍 observability
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG | 🔍 observability
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE | 🔍 observability
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z | 🔍 observability
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT | 🔍 observability
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW | 🔍 observability
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE | 🔍 observability

🌐 Cross-language Conformance (9 failed)

python (9 failed):

• deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0ZWXYSJK22VDCG6YRXP6Q4B
• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE

vercel-multi-region (1 failed)

nextjs-turbopack (1 failed):

• multi-region (world-vercel) hooks on non-iad1 runs hook created by a sfo1 run resolves by token and resumes the run

⚠️ 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.

• deploymentId: 'latest' is a no-op in non-Vercel worlds (nitro)
• hookWithSleepFinalStepWorkflow - step only on final payload (nextjs-webpack)
• hookWorkflow (vite)
• 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.

34 infra events

• cold-start-warmup · suite warmup (python) · at 20:37:39Z · abandoned wrun_41M0ZWJ7WC0GM60ZYBBV2EBQD7 · (+7 more)
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1214
• run-pickup-stall · sleepingWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1213
• run-pickup-stall · nullByteWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH80GVRAN0AWJ7YQ6MY
• run-pickup-stall · promiseAllWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWGY0GJMHCXMPNX6S92S
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWSR0GP3W2DTFB1K69G6
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:38:28Z · abandoned wrun_41M0ZWPVWH0GHX1S11MM5REDP6
• run-pickup-stall · sleepingWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRH0GWH567ZD71WNDMP
• run-pickup-stall · nullByteWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRV0GYJ9PNYHYS89384
• run-pickup-stall · promiseAllWorkflow (python) · at 20:38:57Z · abandoned wrun_41M0ZWQR210GYB5TX06QESX365
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQRH80GJW6FHAQ8V97R9Y
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQV270GWF3V8QH1A8TWMJ
• cold-start-warmup · suite warmup (tanstack-start) · at 20:39:32Z · abandoned wrun_01M0ZWRFCR447TPW9VBW47CCSW
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:40:39Z · abandoned wrun_41M0ZWSRM40GTN4NF0CM5BMN4Z
• cold-start-warmup · suite warmup (python) · at 20:40:49Z · abandoned wrun_01M0ZWR0BZGWCSF0604B0QCS6V · (+7 more)
• run-pickup-stall · sleepingWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH26HN0J7P54QFWRCBT
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGXC6S647VGAZRBBDM9
• run-pickup-stall · nullByteWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH4WVZDC8P1N4TTD1M0
• run-pickup-stall · promiseAllWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGYQHTPNF5W7QPC4MRT
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH3465Q0K3EF487NGED
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:41:18Z · abandoned wrun_41M0ZWSWDZ0GQJ7Q4JYSDDHBTC
• run-pickup-stall · promiseAllWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4EWN54KW4THDWD7T8P
• run-pickup-stall · sleepingWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4HPPDBEHP4NVYFDGN5
• run-pickup-stall · nullByteWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4PCAYE9B8P00J4SCJM
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4BX3YXM3R76WC7CEBX
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4JHHTBRP5FD3DY6392
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQRX9WM6Z4GWW3WJP2D
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQY8R1SKMNWJ5YA9TVE
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQZ8VVKD8GBGM62NTDW
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0838BE3N4FNY4W5KSPK6
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0836388GCBWB0RZF60FW
• run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (nextjs-webpack) · at 20:43:55Z · abandoned wrun_01M0ZX0WB1WDKJYXCQT7X2M0B3
• run-pickup-stall · concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (nextjs-webpack) · at 20:44:00Z · abandoned wrun_01M0ZX11CSS1MAQFSQMF187QW0
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:44:04Z · abandoned wrun_01M0ZX15B28M5P8J1N1VPYADWG

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
❌ ▲ Vercel Production	3570	8	742	4320
✅ 💻 Local Development	3922	0	558	4480
✅ 📦 Local Production	3922	0	558	4480
✅ 🐘 Local Postgres	3922	0	558	4480
✅ 🪟 Windows	320	0	0	320
❌ 🌐 Cross-language Conformance	0	9	132	141
✅ vercel-http-transport	817	0	143	960
❌ vercel-multi-region	26	1	0	27
✅ vercel-ws-transport	553	0	87	640
Total	17052	18	2778	19848

Details by Category

❌ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	132	0	28
✅ astro-quickjs	132	0	28
✅ example-node	132	0	28
✅ example-quickjs	132	0	28
✅ express-node	132	0	28
✅ express-quickjs	132	0	28
✅ fastify-node	132	0	28
✅ fastify-quickjs	132	0	28
✅ hono-node	132	0	28
✅ hono-quickjs	132	0	28
✅ nest-node	132	0	28
✅ nest-quickjs	132	0	28
✅ nextjs-turbopack-node	157	0	3
✅ nextjs-turbopack-quickjs	157	0	3
✅ nextjs-webpack-node	157	0	3
✅ nextjs-webpack-quickjs	157	0	3
✅ nitro-node	132	0	28
✅ nitro-quickjs	132	0	28
✅ nuxt-node	132	0	28
✅ nuxt-quickjs	132	0	28
❌ python-node	0	8	152
✅ sveltekit-node	151	0	9
✅ sveltekit-quickjs	151	0	9
✅ tanstack-start-node	132	0	28
✅ tanstack-start-quickjs	132	0	28
✅ vite-node	132	0	28
✅ vite-quickjs	132	0	28

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	160	0	0
✅ nextjs-turbopack-quickjs	160	0	0

❌ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
❌ python	0	9	132

✅ vercel-http-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ hono	132	0	28
✅ nextjs-turbopack	157	0	3
✅ nitro	132	0	28
✅ vite	132	0	28

❌ vercel-multi-region

App	Passed	Failed	Skipped
❌ nextjs-turbopack	26	1	0

✅ vercel-ws-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ nextjs-turbopack	157	0	3
✅ vite	132	0	28

---

📋 View full workflow run

[github-actions]

📊 Workflow Benchmarks

commit db061c6 · Wed, 26 Aug 2026 21:00:08 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1329 (+39%) 🔻	1506 🔴 (+42%) 🔻	1575 🔴 (+43%) 🔻	1643 🔴 (+40%) 🔻	30
TTFS	stream	1061 (+539%) 🔻	1376 🔴 (+30%) 🔻	1420 🔴 (+25%) 🔻	1651 🔴 (+37%) 🔻	30
TTFS	hook + stream	493 (-61%) 💚	1633 🔴 (+22%) 🔻	1659 🔴 (+22%) 🔻	1707 🔴 (-24%) 💚	30
Fan-out TTFS	Promise.all(100 steps)	606 (+30%) 🔻	968 (+30%) 🔻	989 (-42%) 💚	2274 (-50%) 💚	10
Fan-out TTLS	Promise.all(100 steps)	2043 (+12%)	5113 (+23%) 🔻	5536 (+12%)	9647 (-2.8%)	10
STSO	1020 steps (inline)	89 (-14%)	135 (+5.5%)	160 (+8.1%)	217 (-26%) 💚	1019
WO	1020 steps	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	1
CRTT	first chunk (pooled)	110 (+41%) 🔻	148 (+11%)	189 (+12%)	270 (-18%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	125 (+21%)	167 (+31%)	213 (+17%)	312 (-21%)	123 (-24%)	10
size sweep (100/s, 160B-12KB)	132 (+25%)	174 (+7%)	236 (-50%)	356 (-60%)	155 (-32%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	135 (-20%)	1102 (+748%)	3758 (+2206%)	5151 (+787%)	362 (-15%)	3
replay eve-gpt-5.6-sol-2000t (1x)	136 (-1%)	151 (+11%)	199 (+11%)	321 (-59%)	255 (-60%)	2
replay eve-gpt-5.6-sol-2000t (2x)	171 (+29%)	194 (-2%)	377 (+17%)	931 (+63%)	301 (+11%)	3

📈 STSO distribution vs main (inline / queue-hop histograms)

1020 steps (inline)

Cumulative STSO time: main 134890ms → this run 136346ms (Δ +1456ms, +1%)

 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████┃█ main 924 this 869 -55
150-200 ms ██┃ main 76 this 133 +57
200-250 ms ┃ main 4 this 8 +4
250-300 ms ┃ main 5 this 3 -2
300-350 ms ┃ main 1 this 5 +4
350-400 ms ┃ main 1 this 0 -1
650-700 ms ┃ main 1 this 0 -1
700-750 ms ┃ main 2 this 0 -2
750-800 ms ┃ main 1 this 0 -1
800-850 ms ┃ main 2 this 0 -2
1150-1200 ms ┃ main 1 this 0 -1
1200-1250 ms ┃ main 1 this 0 -1

📈 CRTT drill-down vs main (RTT distributions & profiles)

variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▂█▁···· 133.7 (+23%) 124 (+27%) 213 (+17%) 312 (-21%) 3000
sweep ······▂█▂···· 140.1 (-4%) 127 (+25%) 236 (-50%) 356 (-60%) 3000
gw 1x ·····▁▃█▁▁▁▁▁ 397.7 (+245%) 118 (+16%) 3758 (+2206%) 5151 (+787%) 5295
eve 1x ·····▁▄█▁···· 127 (+5%) 118 (+26%) 199 (+11%) 321 (-59%) 5186
eve 2x ·····▁▂█▃▁··· 173.6 (+11%) 145 (+12%) 377 (+17%) 931 (+63%) 7779

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

control █▂▆▃▁▁▃▅▂▅ 125–148ms
sweep ▆▆█▅▆▂▁▅▆▆ 122–153ms
gw 1x ▁▁▁▁▁█▅▂▁▁ 115–1601ms
eve 1x ▂▂▅▅▁▄▇█▄▆ 114–141ms
eve 2x ▁▁▂▁▁▁▂█▃▁ 129–382ms

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

sweep ▃▆█▃▂▂▁ 139–142ms

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

control ▁▇▂▃▅▅▄▁▄█ 33–44ms
sweep ▁▂█▅▆▅▅▆▅▄ 40–56ms
gw 1x ▁▂▂▁█▄▁▂▂▂ 33–80ms
eve 1x ▁▃▁▃▂▄▆▃█▅ 22–27ms
eve 2x ▆▂▂▃▄▁▁▂█▄ 23–31ms

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.}

[github-actions]

Sim World

Simulated world deterministic testing for races. Traces

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

fence=per-spec

scenario	outcome	events	virt	replay	violations
✅ smoke-no-steps	completed	3	0ms	ok	0
✅ smoke-one-step	completed	6	0ms	ok	0
✅ hook-at-step-started	completed	12	0ms	ok	0
✅ hook-at-step-completed	completed	12	0ms	ok	0
✅ hook-at-hook-created	completed	12	0ms	ok	0
✅ deadline-hook-wins	completed	7	1.0h	ok	0
✅ deadline-expires	completed	7	1.0h	ok	0
✅ long-sleep	completed	11	30.0d	ok	0
✅ hook-never-arrives	stalled	3	0ms	skipped	0
✅ step-retries-twice	completed	10	2.0s	ok	0
✅ parallel-steps	completed	9	0ms	ok	0
✅ hook-on-execution-state	completed	12	0ms	ok	0
✅ peek-hook-before-branch	completed	12	0ms	ok	0
✅ peek-hook-after-branch	completed	12	0ms	ok	0
✅ peek-hook-at-registration	completed	12	0ms	ok	0
✅ race-hook-before-probe	completed	12	0ms	ok	0
✅ race-hook-after-probe	completed	12	0ms	ok	0
✅ race-duplicate-delivery	completed	13	0ms	ok	0
✅ attr-hook-before-step	completed	11	0ms	ok	0
✅ attr-hook-after-step	completed	11	0ms	ok	0
✅ attr-from-step-body	completed	13	0ms	ok	0
✅ fork-hook-after-timeout	completed	14	1.0m	ok	0
✅ fork-hook-before-timeout	completed	14	1.0m	ok	0
✅ count-hook-after-timeout	completed	17	1.0m	ok	0
✅ count-hook-before-timeout	completed	20	1.0m	ok	0
✅ stale-read-step-count-fork	completed	20	1.0m	ok	0
✅ stale-read-equal-step-counts	completed	14	1.0m	ok	0
✅ step-vs-step-fork	completed	12	0ms	ok	0
✅ step-vs-step-fork-fenced	completed	12	0ms	ok	0
✅ fence-catches-benign-direction	completed	12	5ms	ok	0
✅ in-flight-before-decision	completed	17	1.0m	ok	0
❌ in-flight-before-decision-counted	completed	17	1.0m	ok	0
✅ in-flight-after-decision	completed	19	2.0m	ok	0
✅ stale-read-step-count-fork-fenced	completed	20	1.0m	ok	0
✅ fork-hook-wins	completed	13	1.0m	ok	0
✅ fork-timeout-wins	completed	13	1.0m	ok	0
✅ unclaimed-payload-under-fork	completed	17	1.0m	ok	0
✅ claimed-payload-under-fork	completed	17	1.0m	ok	0
✅ writers-independent-step-bodies	completed	12	0ms	ok	0
✅ writers-scripted-tempo	completed	12	0ms	ok	0
✅ cancel-mid-step	cancelled	7	0ms	skipped	0

Full trace: world-sim.txt

[github-actions]

Framework	Flow route	Step reg.	Framework output
hono	200.9 KiB (±0)	40.3 KiB (±0)	1.76 MiB (+7 B)
nextjs-turbopack	206.3 KiB (±0)	439 B (±0)	763.1 KiB (+7 B)

About these numbers

Sizes are gzip; parentheses show the change against main.
Flow route and Step reg. gate this job, on raw bytes rather than the gzip shown, at max(2%, 50.0 KiB). Framework output is informational.

db061c6 · run

[github-actions]

Backport PR opened against stable: #3827. Merge conflicts were resolved by AI — please review carefully. (backport job run)

[AndrewBarba]

Description

world-local creates a shutdown AbortController, but the controller was only connected to delivery delays and retry backoffs. An HTTP delivery with disabled transport timeouts therefore remained active when the World closed, and undici's graceful Agent.close() waited indefinitely for that request to finish.

Pass the existing close signal to both HTTP transports. Closing the World now aborts its active delivery requests before releasing the transport pool, while preserving graceful agent cleanup and the durable message for recovery after restart.

This was exposed by vercel/eve#2609, which disables local delivery timeouts to prevent healthy long-running agent turns from being redelivered.

How did you test your changes?

Added a world-local queue regression test with both transport timeouts disabled and a server that accepts but never completes the delivery. The test reports timed-out on main and closes immediately with this change.

• pnpm exec turbo build --filter=@workflow/world-local...
• pnpm --filter @workflow/world-local exec vitest run src/queue.test.ts — 26 passed
• pnpm --filter @workflow/world-local typecheck
• pnpm exec biome check packages/world-local/src/queue.ts packages/world-local/src/queue.test.ts — passed with the two existing complexity warnings

PR Checklist - Required to merge

• 📦 pnpm changeset was run to create a changelog for this PR
• 🔒 DCO sign-off passes (run git commit --signoff on your commits)
• 📝 Ping @vercel/workflow in a comment once the PR is ready, and the above checklist is complete

[AndrewBarba]

@vercel/workflow ready for review.

[changeset-bot]

🦋 Changeset detected

Latest commit: db061c6

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

This PR includes changesets to release 18 packages

Name	Type
@workflow/world-local	Patch
@workflow/cli	Patch
@workflow/core	Patch
@workflow/vitest	Patch
@workflow/web	Patch
@workflow/world-postgres	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/web-shared	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

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

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-nextjs-workflow-webpack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-astro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-express-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-fastify-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-hono-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nestjs-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nitro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nuxt-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-python-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-sveltekit-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-tanstack-start-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-vite-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-docs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-swc-playground	Building	Preview, v0	Aug 26, 2026 8:36pm
workflow-tarballs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-web	Ready	Preview, v0	Aug 26, 2026 8:36pm

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

▲ Vercel Production (8 failed)

python-node (8 failed):

• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S | 🔍 observability
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ | 🔍 observability
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG | 🔍 observability
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE | 🔍 observability
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z | 🔍 observability
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT | 🔍 observability
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW | 🔍 observability
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE | 🔍 observability

🌐 Cross-language Conformance (9 failed)

python (9 failed):

• deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0ZWXYSJK22VDCG6YRXP6Q4B
• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE

vercel-multi-region (1 failed)

nextjs-turbopack (1 failed):

• multi-region (world-vercel) hooks on non-iad1 runs hook created by a sfo1 run resolves by token and resumes the run

⚠️ 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.

• deploymentId: 'latest' is a no-op in non-Vercel worlds (nitro)
• hookWithSleepFinalStepWorkflow - step only on final payload (nextjs-webpack)
• hookWorkflow (vite)
• 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.

34 infra events

• cold-start-warmup · suite warmup (python) · at 20:37:39Z · abandoned wrun_41M0ZWJ7WC0GM60ZYBBV2EBQD7 · (+7 more)
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1214
• run-pickup-stall · sleepingWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1213
• run-pickup-stall · nullByteWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH80GVRAN0AWJ7YQ6MY
• run-pickup-stall · promiseAllWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWGY0GJMHCXMPNX6S92S
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWSR0GP3W2DTFB1K69G6
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:38:28Z · abandoned wrun_41M0ZWPVWH0GHX1S11MM5REDP6
• run-pickup-stall · sleepingWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRH0GWH567ZD71WNDMP
• run-pickup-stall · nullByteWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRV0GYJ9PNYHYS89384
• run-pickup-stall · promiseAllWorkflow (python) · at 20:38:57Z · abandoned wrun_41M0ZWQR210GYB5TX06QESX365
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQRH80GJW6FHAQ8V97R9Y
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQV270GWF3V8QH1A8TWMJ
• cold-start-warmup · suite warmup (tanstack-start) · at 20:39:32Z · abandoned wrun_01M0ZWRFCR447TPW9VBW47CCSW
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:40:39Z · abandoned wrun_41M0ZWSRM40GTN4NF0CM5BMN4Z
• cold-start-warmup · suite warmup (python) · at 20:40:49Z · abandoned wrun_01M0ZWR0BZGWCSF0604B0QCS6V · (+7 more)
• run-pickup-stall · sleepingWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH26HN0J7P54QFWRCBT
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGXC6S647VGAZRBBDM9
• run-pickup-stall · nullByteWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH4WVZDC8P1N4TTD1M0
• run-pickup-stall · promiseAllWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGYQHTPNF5W7QPC4MRT
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH3465Q0K3EF487NGED
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:41:18Z · abandoned wrun_41M0ZWSWDZ0GQJ7Q4JYSDDHBTC
• run-pickup-stall · promiseAllWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4EWN54KW4THDWD7T8P
• run-pickup-stall · sleepingWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4HPPDBEHP4NVYFDGN5
• run-pickup-stall · nullByteWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4PCAYE9B8P00J4SCJM
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4BX3YXM3R76WC7CEBX
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4JHHTBRP5FD3DY6392
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQRX9WM6Z4GWW3WJP2D
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQY8R1SKMNWJ5YA9TVE
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQZ8VVKD8GBGM62NTDW
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0838BE3N4FNY4W5KSPK6
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0836388GCBWB0RZF60FW
• run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (nextjs-webpack) · at 20:43:55Z · abandoned wrun_01M0ZX0WB1WDKJYXCQT7X2M0B3
• run-pickup-stall · concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (nextjs-webpack) · at 20:44:00Z · abandoned wrun_01M0ZX11CSS1MAQFSQMF187QW0
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:44:04Z · abandoned wrun_01M0ZX15B28M5P8J1N1VPYADWG

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
❌ ▲ Vercel Production	3570	8	742	4320
✅ 💻 Local Development	3922	0	558	4480
✅ 📦 Local Production	3922	0	558	4480
✅ 🐘 Local Postgres	3922	0	558	4480
✅ 🪟 Windows	320	0	0	320
❌ 🌐 Cross-language Conformance	0	9	132	141
✅ vercel-http-transport	817	0	143	960
❌ vercel-multi-region	26	1	0	27
✅ vercel-ws-transport	553	0	87	640
Total	17052	18	2778	19848

Details by Category

❌ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	132	0	28
✅ astro-quickjs	132	0	28
✅ example-node	132	0	28
✅ example-quickjs	132	0	28
✅ express-node	132	0	28
✅ express-quickjs	132	0	28
✅ fastify-node	132	0	28
✅ fastify-quickjs	132	0	28
✅ hono-node	132	0	28
✅ hono-quickjs	132	0	28
✅ nest-node	132	0	28
✅ nest-quickjs	132	0	28
✅ nextjs-turbopack-node	157	0	3
✅ nextjs-turbopack-quickjs	157	0	3
✅ nextjs-webpack-node	157	0	3
✅ nextjs-webpack-quickjs	157	0	3
✅ nitro-node	132	0	28
✅ nitro-quickjs	132	0	28
✅ nuxt-node	132	0	28
✅ nuxt-quickjs	132	0	28
❌ python-node	0	8	152
✅ sveltekit-node	151	0	9
✅ sveltekit-quickjs	151	0	9
✅ tanstack-start-node	132	0	28
✅ tanstack-start-quickjs	132	0	28
✅ vite-node	132	0	28
✅ vite-quickjs	132	0	28

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	160	0	0
✅ nextjs-turbopack-quickjs	160	0	0

❌ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
❌ python	0	9	132

✅ vercel-http-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ hono	132	0	28
✅ nextjs-turbopack	157	0	3
✅ nitro	132	0	28
✅ vite	132	0	28

❌ vercel-multi-region

App	Passed	Failed	Skipped
❌ nextjs-turbopack	26	1	0

✅ vercel-ws-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ nextjs-turbopack	157	0	3
✅ vite	132	0	28

---

📋 View full workflow run

[github-actions]

📊 Workflow Benchmarks

commit db061c6 · Wed, 26 Aug 2026 21:00:08 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1329 (+39%) 🔻	1506 🔴 (+42%) 🔻	1575 🔴 (+43%) 🔻	1643 🔴 (+40%) 🔻	30
TTFS	stream	1061 (+539%) 🔻	1376 🔴 (+30%) 🔻	1420 🔴 (+25%) 🔻	1651 🔴 (+37%) 🔻	30
TTFS	hook + stream	493 (-61%) 💚	1633 🔴 (+22%) 🔻	1659 🔴 (+22%) 🔻	1707 🔴 (-24%) 💚	30
Fan-out TTFS	Promise.all(100 steps)	606 (+30%) 🔻	968 (+30%) 🔻	989 (-42%) 💚	2274 (-50%) 💚	10
Fan-out TTLS	Promise.all(100 steps)	2043 (+12%)	5113 (+23%) 🔻	5536 (+12%)	9647 (-2.8%)	10
STSO	1020 steps (inline)	89 (-14%)	135 (+5.5%)	160 (+8.1%)	217 (-26%) 💚	1019
WO	1020 steps	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	1
CRTT	first chunk (pooled)	110 (+41%) 🔻	148 (+11%)	189 (+12%)	270 (-18%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	125 (+21%)	167 (+31%)	213 (+17%)	312 (-21%)	123 (-24%)	10
size sweep (100/s, 160B-12KB)	132 (+25%)	174 (+7%)	236 (-50%)	356 (-60%)	155 (-32%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	135 (-20%)	1102 (+748%)	3758 (+2206%)	5151 (+787%)	362 (-15%)	3
replay eve-gpt-5.6-sol-2000t (1x)	136 (-1%)	151 (+11%)	199 (+11%)	321 (-59%)	255 (-60%)	2
replay eve-gpt-5.6-sol-2000t (2x)	171 (+29%)	194 (-2%)	377 (+17%)	931 (+63%)	301 (+11%)	3

📈 STSO distribution vs main (inline / queue-hop histograms)

1020 steps (inline)

Cumulative STSO time: main 134890ms → this run 136346ms (Δ +1456ms, +1%)

 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████┃█ main 924 this 869 -55
150-200 ms ██┃ main 76 this 133 +57
200-250 ms ┃ main 4 this 8 +4
250-300 ms ┃ main 5 this 3 -2
300-350 ms ┃ main 1 this 5 +4
350-400 ms ┃ main 1 this 0 -1
650-700 ms ┃ main 1 this 0 -1
700-750 ms ┃ main 2 this 0 -2
750-800 ms ┃ main 1 this 0 -1
800-850 ms ┃ main 2 this 0 -2
1150-1200 ms ┃ main 1 this 0 -1
1200-1250 ms ┃ main 1 this 0 -1

📈 CRTT drill-down vs main (RTT distributions & profiles)

variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▂█▁···· 133.7 (+23%) 124 (+27%) 213 (+17%) 312 (-21%) 3000
sweep ······▂█▂···· 140.1 (-4%) 127 (+25%) 236 (-50%) 356 (-60%) 3000
gw 1x ·····▁▃█▁▁▁▁▁ 397.7 (+245%) 118 (+16%) 3758 (+2206%) 5151 (+787%) 5295
eve 1x ·····▁▄█▁···· 127 (+5%) 118 (+26%) 199 (+11%) 321 (-59%) 5186
eve 2x ·····▁▂█▃▁··· 173.6 (+11%) 145 (+12%) 377 (+17%) 931 (+63%) 7779

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

control █▂▆▃▁▁▃▅▂▅ 125–148ms
sweep ▆▆█▅▆▂▁▅▆▆ 122–153ms
gw 1x ▁▁▁▁▁█▅▂▁▁ 115–1601ms
eve 1x ▂▂▅▅▁▄▇█▄▆ 114–141ms
eve 2x ▁▁▂▁▁▁▂█▃▁ 129–382ms

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

sweep ▃▆█▃▂▂▁ 139–142ms

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

control ▁▇▂▃▅▅▄▁▄█ 33–44ms
sweep ▁▂█▅▆▅▅▆▅▄ 40–56ms
gw 1x ▁▂▂▁█▄▁▂▂▂ 33–80ms
eve 1x ▁▃▁▃▂▄▆▃█▅ 22–27ms
eve 2x ▆▂▂▃▄▁▁▂█▄ 23–31ms

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.}

[github-actions]

Sim World

Simulated world deterministic testing for races. Traces

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

fence=per-spec

scenario	outcome	events	virt	replay	violations
✅ smoke-no-steps	completed	3	0ms	ok	0
✅ smoke-one-step	completed	6	0ms	ok	0
✅ hook-at-step-started	completed	12	0ms	ok	0
✅ hook-at-step-completed	completed	12	0ms	ok	0
✅ hook-at-hook-created	completed	12	0ms	ok	0
✅ deadline-hook-wins	completed	7	1.0h	ok	0
✅ deadline-expires	completed	7	1.0h	ok	0
✅ long-sleep	completed	11	30.0d	ok	0
✅ hook-never-arrives	stalled	3	0ms	skipped	0
✅ step-retries-twice	completed	10	2.0s	ok	0
✅ parallel-steps	completed	9	0ms	ok	0
✅ hook-on-execution-state	completed	12	0ms	ok	0
✅ peek-hook-before-branch	completed	12	0ms	ok	0
✅ peek-hook-after-branch	completed	12	0ms	ok	0
✅ peek-hook-at-registration	completed	12	0ms	ok	0
✅ race-hook-before-probe	completed	12	0ms	ok	0
✅ race-hook-after-probe	completed	12	0ms	ok	0
✅ race-duplicate-delivery	completed	13	0ms	ok	0
✅ attr-hook-before-step	completed	11	0ms	ok	0
✅ attr-hook-after-step	completed	11	0ms	ok	0
✅ attr-from-step-body	completed	13	0ms	ok	0
✅ fork-hook-after-timeout	completed	14	1.0m	ok	0
✅ fork-hook-before-timeout	completed	14	1.0m	ok	0
✅ count-hook-after-timeout	completed	17	1.0m	ok	0
✅ count-hook-before-timeout	completed	20	1.0m	ok	0
✅ stale-read-step-count-fork	completed	20	1.0m	ok	0
✅ stale-read-equal-step-counts	completed	14	1.0m	ok	0
✅ step-vs-step-fork	completed	12	0ms	ok	0
✅ step-vs-step-fork-fenced	completed	12	0ms	ok	0
✅ fence-catches-benign-direction	completed	12	5ms	ok	0
✅ in-flight-before-decision	completed	17	1.0m	ok	0
❌ in-flight-before-decision-counted	completed	17	1.0m	ok	0
✅ in-flight-after-decision	completed	19	2.0m	ok	0
✅ stale-read-step-count-fork-fenced	completed	20	1.0m	ok	0
✅ fork-hook-wins	completed	13	1.0m	ok	0
✅ fork-timeout-wins	completed	13	1.0m	ok	0
✅ unclaimed-payload-under-fork	completed	17	1.0m	ok	0
✅ claimed-payload-under-fork	completed	17	1.0m	ok	0
✅ writers-independent-step-bodies	completed	12	0ms	ok	0
✅ writers-scripted-tempo	completed	12	0ms	ok	0
✅ cancel-mid-step	cancelled	7	0ms	skipped	0

Full trace: world-sim.txt

[github-actions]

Framework	Flow route	Step reg.	Framework output
hono	200.9 KiB (±0)	40.3 KiB (±0)	1.76 MiB (+7 B)
nextjs-turbopack	206.3 KiB (±0)	439 B (±0)	763.1 KiB (+7 B)

About these numbers

Sizes are gzip; parentheses show the change against main.
Flow route and Step reg. gate this job, on raw bytes rather than the gzip shown, at max(2%, 50.0 KiB). Framework output is informational.

db061c6 · run

[github-actions]

Backport PR opened against stable: #3827. Merge conflicts were resolved by AI — please review carefully. (backport job run)

[AndrewBarba]

Description

world-local creates a shutdown AbortController, but the controller was only connected to delivery delays and retry backoffs. An HTTP delivery with disabled transport timeouts therefore remained active when the World closed, and undici's graceful Agent.close() waited indefinitely for that request to finish.

Pass the existing close signal to both HTTP transports. Closing the World now aborts its active delivery requests before releasing the transport pool, while preserving graceful agent cleanup and the durable message for recovery after restart.

This was exposed by vercel/eve#2609, which disables local delivery timeouts to prevent healthy long-running agent turns from being redelivered.

How did you test your changes?

Added a world-local queue regression test with both transport timeouts disabled and a server that accepts but never completes the delivery. The test reports timed-out on main and closes immediately with this change.

• pnpm exec turbo build --filter=@workflow/world-local...
• pnpm --filter @workflow/world-local exec vitest run src/queue.test.ts — 26 passed
• pnpm --filter @workflow/world-local typecheck
• pnpm exec biome check packages/world-local/src/queue.ts packages/world-local/src/queue.test.ts — passed with the two existing complexity warnings

PR Checklist - Required to merge

• 📦 pnpm changeset was run to create a changelog for this PR
• 🔒 DCO sign-off passes (run git commit --signoff on your commits)
• 📝 Ping @vercel/workflow in a comment once the PR is ready, and the above checklist is complete

[AndrewBarba]

@vercel/workflow ready for review.

[changeset-bot]

🦋 Changeset detected

Latest commit: db061c6

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

This PR includes changesets to release 18 packages

Name	Type
@workflow/world-local	Patch
@workflow/cli	Patch
@workflow/core	Patch
@workflow/vitest	Patch
@workflow/web	Patch
@workflow/world-postgres	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/web-shared	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

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

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-nextjs-workflow-webpack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-astro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-express-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-fastify-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-hono-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nestjs-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nitro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nuxt-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-python-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-sveltekit-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-tanstack-start-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-vite-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-docs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-swc-playground	Building	Preview, v0	Aug 26, 2026 8:36pm
workflow-tarballs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-web	Ready	Preview, v0	Aug 26, 2026 8:36pm

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

▲ Vercel Production (8 failed)

python-node (8 failed):

• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S | 🔍 observability
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ | 🔍 observability
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG | 🔍 observability
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE | 🔍 observability
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z | 🔍 observability
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT | 🔍 observability
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW | 🔍 observability
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE | 🔍 observability

🌐 Cross-language Conformance (9 failed)

python (9 failed):

• deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0ZWXYSJK22VDCG6YRXP6Q4B
• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE

vercel-multi-region (1 failed)

nextjs-turbopack (1 failed):

• multi-region (world-vercel) hooks on non-iad1 runs hook created by a sfo1 run resolves by token and resumes the run

⚠️ 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.

• deploymentId: 'latest' is a no-op in non-Vercel worlds (nitro)
• hookWithSleepFinalStepWorkflow - step only on final payload (nextjs-webpack)
• hookWorkflow (vite)
• 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.

34 infra events

• cold-start-warmup · suite warmup (python) · at 20:37:39Z · abandoned wrun_41M0ZWJ7WC0GM60ZYBBV2EBQD7 · (+7 more)
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1214
• run-pickup-stall · sleepingWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1213
• run-pickup-stall · nullByteWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH80GVRAN0AWJ7YQ6MY
• run-pickup-stall · promiseAllWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWGY0GJMHCXMPNX6S92S
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWSR0GP3W2DTFB1K69G6
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:38:28Z · abandoned wrun_41M0ZWPVWH0GHX1S11MM5REDP6
• run-pickup-stall · sleepingWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRH0GWH567ZD71WNDMP
• run-pickup-stall · nullByteWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRV0GYJ9PNYHYS89384
• run-pickup-stall · promiseAllWorkflow (python) · at 20:38:57Z · abandoned wrun_41M0ZWQR210GYB5TX06QESX365
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQRH80GJW6FHAQ8V97R9Y
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQV270GWF3V8QH1A8TWMJ
• cold-start-warmup · suite warmup (tanstack-start) · at 20:39:32Z · abandoned wrun_01M0ZWRFCR447TPW9VBW47CCSW
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:40:39Z · abandoned wrun_41M0ZWSRM40GTN4NF0CM5BMN4Z
• cold-start-warmup · suite warmup (python) · at 20:40:49Z · abandoned wrun_01M0ZWR0BZGWCSF0604B0QCS6V · (+7 more)
• run-pickup-stall · sleepingWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH26HN0J7P54QFWRCBT
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGXC6S647VGAZRBBDM9
• run-pickup-stall · nullByteWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH4WVZDC8P1N4TTD1M0
• run-pickup-stall · promiseAllWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGYQHTPNF5W7QPC4MRT
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH3465Q0K3EF487NGED
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:41:18Z · abandoned wrun_41M0ZWSWDZ0GQJ7Q4JYSDDHBTC
• run-pickup-stall · promiseAllWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4EWN54KW4THDWD7T8P
• run-pickup-stall · sleepingWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4HPPDBEHP4NVYFDGN5
• run-pickup-stall · nullByteWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4PCAYE9B8P00J4SCJM
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4BX3YXM3R76WC7CEBX
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4JHHTBRP5FD3DY6392
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQRX9WM6Z4GWW3WJP2D
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQY8R1SKMNWJ5YA9TVE
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQZ8VVKD8GBGM62NTDW
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0838BE3N4FNY4W5KSPK6
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0836388GCBWB0RZF60FW
• run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (nextjs-webpack) · at 20:43:55Z · abandoned wrun_01M0ZX0WB1WDKJYXCQT7X2M0B3
• run-pickup-stall · concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (nextjs-webpack) · at 20:44:00Z · abandoned wrun_01M0ZX11CSS1MAQFSQMF187QW0
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:44:04Z · abandoned wrun_01M0ZX15B28M5P8J1N1VPYADWG

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
❌ ▲ Vercel Production	3570	8	742	4320
✅ 💻 Local Development	3922	0	558	4480
✅ 📦 Local Production	3922	0	558	4480
✅ 🐘 Local Postgres	3922	0	558	4480
✅ 🪟 Windows	320	0	0	320
❌ 🌐 Cross-language Conformance	0	9	132	141
✅ vercel-http-transport	817	0	143	960
❌ vercel-multi-region	26	1	0	27
✅ vercel-ws-transport	553	0	87	640
Total	17052	18	2778	19848

Details by Category

❌ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	132	0	28
✅ astro-quickjs	132	0	28
✅ example-node	132	0	28
✅ example-quickjs	132	0	28
✅ express-node	132	0	28
✅ express-quickjs	132	0	28
✅ fastify-node	132	0	28
✅ fastify-quickjs	132	0	28
✅ hono-node	132	0	28
✅ hono-quickjs	132	0	28
✅ nest-node	132	0	28
✅ nest-quickjs	132	0	28
✅ nextjs-turbopack-node	157	0	3
✅ nextjs-turbopack-quickjs	157	0	3
✅ nextjs-webpack-node	157	0	3
✅ nextjs-webpack-quickjs	157	0	3
✅ nitro-node	132	0	28
✅ nitro-quickjs	132	0	28
✅ nuxt-node	132	0	28
✅ nuxt-quickjs	132	0	28
❌ python-node	0	8	152
✅ sveltekit-node	151	0	9
✅ sveltekit-quickjs	151	0	9
✅ tanstack-start-node	132	0	28
✅ tanstack-start-quickjs	132	0	28
✅ vite-node	132	0	28
✅ vite-quickjs	132	0	28

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	160	0	0
✅ nextjs-turbopack-quickjs	160	0	0

❌ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
❌ python	0	9	132

✅ vercel-http-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ hono	132	0	28
✅ nextjs-turbopack	157	0	3
✅ nitro	132	0	28
✅ vite	132	0	28

❌ vercel-multi-region

App	Passed	Failed	Skipped
❌ nextjs-turbopack	26	1	0

✅ vercel-ws-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ nextjs-turbopack	157	0	3
✅ vite	132	0	28

---

📋 View full workflow run

[github-actions]

📊 Workflow Benchmarks

commit db061c6 · Wed, 26 Aug 2026 21:00:08 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1329 (+39%) 🔻	1506 🔴 (+42%) 🔻	1575 🔴 (+43%) 🔻	1643 🔴 (+40%) 🔻	30
TTFS	stream	1061 (+539%) 🔻	1376 🔴 (+30%) 🔻	1420 🔴 (+25%) 🔻	1651 🔴 (+37%) 🔻	30
TTFS	hook + stream	493 (-61%) 💚	1633 🔴 (+22%) 🔻	1659 🔴 (+22%) 🔻	1707 🔴 (-24%) 💚	30
Fan-out TTFS	Promise.all(100 steps)	606 (+30%) 🔻	968 (+30%) 🔻	989 (-42%) 💚	2274 (-50%) 💚	10
Fan-out TTLS	Promise.all(100 steps)	2043 (+12%)	5113 (+23%) 🔻	5536 (+12%)	9647 (-2.8%)	10
STSO	1020 steps (inline)	89 (-14%)	135 (+5.5%)	160 (+8.1%)	217 (-26%) 💚	1019
WO	1020 steps	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	1
CRTT	first chunk (pooled)	110 (+41%) 🔻	148 (+11%)	189 (+12%)	270 (-18%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	125 (+21%)	167 (+31%)	213 (+17%)	312 (-21%)	123 (-24%)	10
size sweep (100/s, 160B-12KB)	132 (+25%)	174 (+7%)	236 (-50%)	356 (-60%)	155 (-32%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	135 (-20%)	1102 (+748%)	3758 (+2206%)	5151 (+787%)	362 (-15%)	3
replay eve-gpt-5.6-sol-2000t (1x)	136 (-1%)	151 (+11%)	199 (+11%)	321 (-59%)	255 (-60%)	2
replay eve-gpt-5.6-sol-2000t (2x)	171 (+29%)	194 (-2%)	377 (+17%)	931 (+63%)	301 (+11%)	3

📈 STSO distribution vs main (inline / queue-hop histograms)

1020 steps (inline)

Cumulative STSO time: main 134890ms → this run 136346ms (Δ +1456ms, +1%)

 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████┃█ main 924 this 869 -55
150-200 ms ██┃ main 76 this 133 +57
200-250 ms ┃ main 4 this 8 +4
250-300 ms ┃ main 5 this 3 -2
300-350 ms ┃ main 1 this 5 +4
350-400 ms ┃ main 1 this 0 -1
650-700 ms ┃ main 1 this 0 -1
700-750 ms ┃ main 2 this 0 -2
750-800 ms ┃ main 1 this 0 -1
800-850 ms ┃ main 2 this 0 -2
1150-1200 ms ┃ main 1 this 0 -1
1200-1250 ms ┃ main 1 this 0 -1

📈 CRTT drill-down vs main (RTT distributions & profiles)

variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▂█▁···· 133.7 (+23%) 124 (+27%) 213 (+17%) 312 (-21%) 3000
sweep ······▂█▂···· 140.1 (-4%) 127 (+25%) 236 (-50%) 356 (-60%) 3000
gw 1x ·····▁▃█▁▁▁▁▁ 397.7 (+245%) 118 (+16%) 3758 (+2206%) 5151 (+787%) 5295
eve 1x ·····▁▄█▁···· 127 (+5%) 118 (+26%) 199 (+11%) 321 (-59%) 5186
eve 2x ·····▁▂█▃▁··· 173.6 (+11%) 145 (+12%) 377 (+17%) 931 (+63%) 7779

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

control █▂▆▃▁▁▃▅▂▅ 125–148ms
sweep ▆▆█▅▆▂▁▅▆▆ 122–153ms
gw 1x ▁▁▁▁▁█▅▂▁▁ 115–1601ms
eve 1x ▂▂▅▅▁▄▇█▄▆ 114–141ms
eve 2x ▁▁▂▁▁▁▂█▃▁ 129–382ms

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

sweep ▃▆█▃▂▂▁ 139–142ms

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

control ▁▇▂▃▅▅▄▁▄█ 33–44ms
sweep ▁▂█▅▆▅▅▆▅▄ 40–56ms
gw 1x ▁▂▂▁█▄▁▂▂▂ 33–80ms
eve 1x ▁▃▁▃▂▄▆▃█▅ 22–27ms
eve 2x ▆▂▂▃▄▁▁▂█▄ 23–31ms

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.}

[github-actions]

Sim World

Simulated world deterministic testing for races. Traces

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

fence=per-spec

scenario	outcome	events	virt	replay	violations
✅ smoke-no-steps	completed	3	0ms	ok	0
✅ smoke-one-step	completed	6	0ms	ok	0
✅ hook-at-step-started	completed	12	0ms	ok	0
✅ hook-at-step-completed	completed	12	0ms	ok	0
✅ hook-at-hook-created	completed	12	0ms	ok	0
✅ deadline-hook-wins	completed	7	1.0h	ok	0
✅ deadline-expires	completed	7	1.0h	ok	0
✅ long-sleep	completed	11	30.0d	ok	0
✅ hook-never-arrives	stalled	3	0ms	skipped	0
✅ step-retries-twice	completed	10	2.0s	ok	0
✅ parallel-steps	completed	9	0ms	ok	0
✅ hook-on-execution-state	completed	12	0ms	ok	0
✅ peek-hook-before-branch	completed	12	0ms	ok	0
✅ peek-hook-after-branch	completed	12	0ms	ok	0
✅ peek-hook-at-registration	completed	12	0ms	ok	0
✅ race-hook-before-probe	completed	12	0ms	ok	0
✅ race-hook-after-probe	completed	12	0ms	ok	0
✅ race-duplicate-delivery	completed	13	0ms	ok	0
✅ attr-hook-before-step	completed	11	0ms	ok	0
✅ attr-hook-after-step	completed	11	0ms	ok	0
✅ attr-from-step-body	completed	13	0ms	ok	0
✅ fork-hook-after-timeout	completed	14	1.0m	ok	0
✅ fork-hook-before-timeout	completed	14	1.0m	ok	0
✅ count-hook-after-timeout	completed	17	1.0m	ok	0
✅ count-hook-before-timeout	completed	20	1.0m	ok	0
✅ stale-read-step-count-fork	completed	20	1.0m	ok	0
✅ stale-read-equal-step-counts	completed	14	1.0m	ok	0
✅ step-vs-step-fork	completed	12	0ms	ok	0
✅ step-vs-step-fork-fenced	completed	12	0ms	ok	0
✅ fence-catches-benign-direction	completed	12	5ms	ok	0
✅ in-flight-before-decision	completed	17	1.0m	ok	0
❌ in-flight-before-decision-counted	completed	17	1.0m	ok	0
✅ in-flight-after-decision	completed	19	2.0m	ok	0
✅ stale-read-step-count-fork-fenced	completed	20	1.0m	ok	0
✅ fork-hook-wins	completed	13	1.0m	ok	0
✅ fork-timeout-wins	completed	13	1.0m	ok	0
✅ unclaimed-payload-under-fork	completed	17	1.0m	ok	0
✅ claimed-payload-under-fork	completed	17	1.0m	ok	0
✅ writers-independent-step-bodies	completed	12	0ms	ok	0
✅ writers-scripted-tempo	completed	12	0ms	ok	0
✅ cancel-mid-step	cancelled	7	0ms	skipped	0

Full trace: world-sim.txt

[github-actions]

Framework	Flow route	Step reg.	Framework output
hono	200.9 KiB (±0)	40.3 KiB (±0)	1.76 MiB (+7 B)
nextjs-turbopack	206.3 KiB (±0)	439 B (±0)	763.1 KiB (+7 B)

About these numbers

Sizes are gzip; parentheses show the change against main.
Flow route and Step reg. gate this job, on raw bytes rather than the gzip shown, at max(2%, 50.0 KiB). Framework output is informational.

db061c6 · run

[github-actions]

Backport PR opened against stable: #3827. Merge conflicts were resolved by AI — please review carefully. (backport job run)

[AndrewBarba]

Description

world-local creates a shutdown AbortController, but the controller was only connected to delivery delays and retry backoffs. An HTTP delivery with disabled transport timeouts therefore remained active when the World closed, and undici's graceful Agent.close() waited indefinitely for that request to finish.

Pass the existing close signal to both HTTP transports. Closing the World now aborts its active delivery requests before releasing the transport pool, while preserving graceful agent cleanup and the durable message for recovery after restart.

This was exposed by vercel/eve#2609, which disables local delivery timeouts to prevent healthy long-running agent turns from being redelivered.

How did you test your changes?

Added a world-local queue regression test with both transport timeouts disabled and a server that accepts but never completes the delivery. The test reports timed-out on main and closes immediately with this change.

• pnpm exec turbo build --filter=@workflow/world-local...
• pnpm --filter @workflow/world-local exec vitest run src/queue.test.ts — 26 passed
• pnpm --filter @workflow/world-local typecheck
• pnpm exec biome check packages/world-local/src/queue.ts packages/world-local/src/queue.test.ts — passed with the two existing complexity warnings

PR Checklist - Required to merge

• 📦 pnpm changeset was run to create a changelog for this PR
• 🔒 DCO sign-off passes (run git commit --signoff on your commits)
• 📝 Ping @vercel/workflow in a comment once the PR is ready, and the above checklist is complete

[AndrewBarba]

@vercel/workflow ready for review.

[changeset-bot]

🦋 Changeset detected

Latest commit: db061c6

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

This PR includes changesets to release 18 packages

Name	Type
@workflow/world-local	Patch
@workflow/cli	Patch
@workflow/core	Patch
@workflow/vitest	Patch
@workflow/web	Patch
@workflow/world-postgres	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/web-shared	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

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

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-nextjs-workflow-webpack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-astro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-express-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-fastify-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-hono-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nestjs-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nitro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nuxt-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-python-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-sveltekit-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-tanstack-start-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-vite-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-docs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-swc-playground	Building	Preview, v0	Aug 26, 2026 8:36pm
workflow-tarballs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-web	Ready	Preview, v0	Aug 26, 2026 8:36pm

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

▲ Vercel Production (8 failed)

python-node (8 failed):

• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S | 🔍 observability
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ | 🔍 observability
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG | 🔍 observability
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE | 🔍 observability
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z | 🔍 observability
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT | 🔍 observability
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW | 🔍 observability
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE | 🔍 observability

🌐 Cross-language Conformance (9 failed)

python (9 failed):

• deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0ZWXYSJK22VDCG6YRXP6Q4B
• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE

vercel-multi-region (1 failed)

nextjs-turbopack (1 failed):

• multi-region (world-vercel) hooks on non-iad1 runs hook created by a sfo1 run resolves by token and resumes the run

⚠️ 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.

• deploymentId: 'latest' is a no-op in non-Vercel worlds (nitro)
• hookWithSleepFinalStepWorkflow - step only on final payload (nextjs-webpack)
• hookWorkflow (vite)
• 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.

34 infra events

• cold-start-warmup · suite warmup (python) · at 20:37:39Z · abandoned wrun_41M0ZWJ7WC0GM60ZYBBV2EBQD7 · (+7 more)
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1214
• run-pickup-stall · sleepingWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1213
• run-pickup-stall · nullByteWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH80GVRAN0AWJ7YQ6MY
• run-pickup-stall · promiseAllWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWGY0GJMHCXMPNX6S92S
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWSR0GP3W2DTFB1K69G6
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:38:28Z · abandoned wrun_41M0ZWPVWH0GHX1S11MM5REDP6
• run-pickup-stall · sleepingWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRH0GWH567ZD71WNDMP
• run-pickup-stall · nullByteWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRV0GYJ9PNYHYS89384
• run-pickup-stall · promiseAllWorkflow (python) · at 20:38:57Z · abandoned wrun_41M0ZWQR210GYB5TX06QESX365
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQRH80GJW6FHAQ8V97R9Y
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQV270GWF3V8QH1A8TWMJ
• cold-start-warmup · suite warmup (tanstack-start) · at 20:39:32Z · abandoned wrun_01M0ZWRFCR447TPW9VBW47CCSW
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:40:39Z · abandoned wrun_41M0ZWSRM40GTN4NF0CM5BMN4Z
• cold-start-warmup · suite warmup (python) · at 20:40:49Z · abandoned wrun_01M0ZWR0BZGWCSF0604B0QCS6V · (+7 more)
• run-pickup-stall · sleepingWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH26HN0J7P54QFWRCBT
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGXC6S647VGAZRBBDM9
• run-pickup-stall · nullByteWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH4WVZDC8P1N4TTD1M0
• run-pickup-stall · promiseAllWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGYQHTPNF5W7QPC4MRT
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH3465Q0K3EF487NGED
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:41:18Z · abandoned wrun_41M0ZWSWDZ0GQJ7Q4JYSDDHBTC
• run-pickup-stall · promiseAllWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4EWN54KW4THDWD7T8P
• run-pickup-stall · sleepingWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4HPPDBEHP4NVYFDGN5
• run-pickup-stall · nullByteWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4PCAYE9B8P00J4SCJM
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4BX3YXM3R76WC7CEBX
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4JHHTBRP5FD3DY6392
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQRX9WM6Z4GWW3WJP2D
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQY8R1SKMNWJ5YA9TVE
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQZ8VVKD8GBGM62NTDW
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0838BE3N4FNY4W5KSPK6
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0836388GCBWB0RZF60FW
• run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (nextjs-webpack) · at 20:43:55Z · abandoned wrun_01M0ZX0WB1WDKJYXCQT7X2M0B3
• run-pickup-stall · concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (nextjs-webpack) · at 20:44:00Z · abandoned wrun_01M0ZX11CSS1MAQFSQMF187QW0
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:44:04Z · abandoned wrun_01M0ZX15B28M5P8J1N1VPYADWG

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
❌ ▲ Vercel Production	3570	8	742	4320
✅ 💻 Local Development	3922	0	558	4480
✅ 📦 Local Production	3922	0	558	4480
✅ 🐘 Local Postgres	3922	0	558	4480
✅ 🪟 Windows	320	0	0	320
❌ 🌐 Cross-language Conformance	0	9	132	141
✅ vercel-http-transport	817	0	143	960
❌ vercel-multi-region	26	1	0	27
✅ vercel-ws-transport	553	0	87	640
Total	17052	18	2778	19848

Details by Category

❌ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	132	0	28
✅ astro-quickjs	132	0	28
✅ example-node	132	0	28
✅ example-quickjs	132	0	28
✅ express-node	132	0	28
✅ express-quickjs	132	0	28
✅ fastify-node	132	0	28
✅ fastify-quickjs	132	0	28
✅ hono-node	132	0	28
✅ hono-quickjs	132	0	28
✅ nest-node	132	0	28
✅ nest-quickjs	132	0	28
✅ nextjs-turbopack-node	157	0	3
✅ nextjs-turbopack-quickjs	157	0	3
✅ nextjs-webpack-node	157	0	3
✅ nextjs-webpack-quickjs	157	0	3
✅ nitro-node	132	0	28
✅ nitro-quickjs	132	0	28
✅ nuxt-node	132	0	28
✅ nuxt-quickjs	132	0	28
❌ python-node	0	8	152
✅ sveltekit-node	151	0	9
✅ sveltekit-quickjs	151	0	9
✅ tanstack-start-node	132	0	28
✅ tanstack-start-quickjs	132	0	28
✅ vite-node	132	0	28
✅ vite-quickjs	132	0	28

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	160	0	0
✅ nextjs-turbopack-quickjs	160	0	0

❌ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
❌ python	0	9	132

✅ vercel-http-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ hono	132	0	28
✅ nextjs-turbopack	157	0	3
✅ nitro	132	0	28
✅ vite	132	0	28

❌ vercel-multi-region

App	Passed	Failed	Skipped
❌ nextjs-turbopack	26	1	0

✅ vercel-ws-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ nextjs-turbopack	157	0	3
✅ vite	132	0	28

---

📋 View full workflow run

[github-actions]

📊 Workflow Benchmarks

commit db061c6 · Wed, 26 Aug 2026 21:00:08 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1329 (+39%) 🔻	1506 🔴 (+42%) 🔻	1575 🔴 (+43%) 🔻	1643 🔴 (+40%) 🔻	30
TTFS	stream	1061 (+539%) 🔻	1376 🔴 (+30%) 🔻	1420 🔴 (+25%) 🔻	1651 🔴 (+37%) 🔻	30
TTFS	hook + stream	493 (-61%) 💚	1633 🔴 (+22%) 🔻	1659 🔴 (+22%) 🔻	1707 🔴 (-24%) 💚	30
Fan-out TTFS	Promise.all(100 steps)	606 (+30%) 🔻	968 (+30%) 🔻	989 (-42%) 💚	2274 (-50%) 💚	10
Fan-out TTLS	Promise.all(100 steps)	2043 (+12%)	5113 (+23%) 🔻	5536 (+12%)	9647 (-2.8%)	10
STSO	1020 steps (inline)	89 (-14%)	135 (+5.5%)	160 (+8.1%)	217 (-26%) 💚	1019
WO	1020 steps	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	1
CRTT	first chunk (pooled)	110 (+41%) 🔻	148 (+11%)	189 (+12%)	270 (-18%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	125 (+21%)	167 (+31%)	213 (+17%)	312 (-21%)	123 (-24%)	10
size sweep (100/s, 160B-12KB)	132 (+25%)	174 (+7%)	236 (-50%)	356 (-60%)	155 (-32%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	135 (-20%)	1102 (+748%)	3758 (+2206%)	5151 (+787%)	362 (-15%)	3
replay eve-gpt-5.6-sol-2000t (1x)	136 (-1%)	151 (+11%)	199 (+11%)	321 (-59%)	255 (-60%)	2
replay eve-gpt-5.6-sol-2000t (2x)	171 (+29%)	194 (-2%)	377 (+17%)	931 (+63%)	301 (+11%)	3

📈 STSO distribution vs main (inline / queue-hop histograms)

1020 steps (inline)

Cumulative STSO time: main 134890ms → this run 136346ms (Δ +1456ms, +1%)

 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████┃█ main 924 this 869 -55
150-200 ms ██┃ main 76 this 133 +57
200-250 ms ┃ main 4 this 8 +4
250-300 ms ┃ main 5 this 3 -2
300-350 ms ┃ main 1 this 5 +4
350-400 ms ┃ main 1 this 0 -1
650-700 ms ┃ main 1 this 0 -1
700-750 ms ┃ main 2 this 0 -2
750-800 ms ┃ main 1 this 0 -1
800-850 ms ┃ main 2 this 0 -2
1150-1200 ms ┃ main 1 this 0 -1
1200-1250 ms ┃ main 1 this 0 -1

📈 CRTT drill-down vs main (RTT distributions & profiles)

variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▂█▁···· 133.7 (+23%) 124 (+27%) 213 (+17%) 312 (-21%) 3000
sweep ······▂█▂···· 140.1 (-4%) 127 (+25%) 236 (-50%) 356 (-60%) 3000
gw 1x ·····▁▃█▁▁▁▁▁ 397.7 (+245%) 118 (+16%) 3758 (+2206%) 5151 (+787%) 5295
eve 1x ·····▁▄█▁···· 127 (+5%) 118 (+26%) 199 (+11%) 321 (-59%) 5186
eve 2x ·····▁▂█▃▁··· 173.6 (+11%) 145 (+12%) 377 (+17%) 931 (+63%) 7779

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

control █▂▆▃▁▁▃▅▂▅ 125–148ms
sweep ▆▆█▅▆▂▁▅▆▆ 122–153ms
gw 1x ▁▁▁▁▁█▅▂▁▁ 115–1601ms
eve 1x ▂▂▅▅▁▄▇█▄▆ 114–141ms
eve 2x ▁▁▂▁▁▁▂█▃▁ 129–382ms

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

sweep ▃▆█▃▂▂▁ 139–142ms

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

control ▁▇▂▃▅▅▄▁▄█ 33–44ms
sweep ▁▂█▅▆▅▅▆▅▄ 40–56ms
gw 1x ▁▂▂▁█▄▁▂▂▂ 33–80ms
eve 1x ▁▃▁▃▂▄▆▃█▅ 22–27ms
eve 2x ▆▂▂▃▄▁▁▂█▄ 23–31ms

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.}

[github-actions]

Sim World

Simulated world deterministic testing for races. Traces

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

fence=per-spec

scenario	outcome	events	virt	replay	violations
✅ smoke-no-steps	completed	3	0ms	ok	0
✅ smoke-one-step	completed	6	0ms	ok	0
✅ hook-at-step-started	completed	12	0ms	ok	0
✅ hook-at-step-completed	completed	12	0ms	ok	0
✅ hook-at-hook-created	completed	12	0ms	ok	0
✅ deadline-hook-wins	completed	7	1.0h	ok	0
✅ deadline-expires	completed	7	1.0h	ok	0
✅ long-sleep	completed	11	30.0d	ok	0
✅ hook-never-arrives	stalled	3	0ms	skipped	0
✅ step-retries-twice	completed	10	2.0s	ok	0
✅ parallel-steps	completed	9	0ms	ok	0
✅ hook-on-execution-state	completed	12	0ms	ok	0
✅ peek-hook-before-branch	completed	12	0ms	ok	0
✅ peek-hook-after-branch	completed	12	0ms	ok	0
✅ peek-hook-at-registration	completed	12	0ms	ok	0
✅ race-hook-before-probe	completed	12	0ms	ok	0
✅ race-hook-after-probe	completed	12	0ms	ok	0
✅ race-duplicate-delivery	completed	13	0ms	ok	0
✅ attr-hook-before-step	completed	11	0ms	ok	0
✅ attr-hook-after-step	completed	11	0ms	ok	0
✅ attr-from-step-body	completed	13	0ms	ok	0
✅ fork-hook-after-timeout	completed	14	1.0m	ok	0
✅ fork-hook-before-timeout	completed	14	1.0m	ok	0
✅ count-hook-after-timeout	completed	17	1.0m	ok	0
✅ count-hook-before-timeout	completed	20	1.0m	ok	0
✅ stale-read-step-count-fork	completed	20	1.0m	ok	0
✅ stale-read-equal-step-counts	completed	14	1.0m	ok	0
✅ step-vs-step-fork	completed	12	0ms	ok	0
✅ step-vs-step-fork-fenced	completed	12	0ms	ok	0
✅ fence-catches-benign-direction	completed	12	5ms	ok	0
✅ in-flight-before-decision	completed	17	1.0m	ok	0
❌ in-flight-before-decision-counted	completed	17	1.0m	ok	0
✅ in-flight-after-decision	completed	19	2.0m	ok	0
✅ stale-read-step-count-fork-fenced	completed	20	1.0m	ok	0
✅ fork-hook-wins	completed	13	1.0m	ok	0
✅ fork-timeout-wins	completed	13	1.0m	ok	0
✅ unclaimed-payload-under-fork	completed	17	1.0m	ok	0
✅ claimed-payload-under-fork	completed	17	1.0m	ok	0
✅ writers-independent-step-bodies	completed	12	0ms	ok	0
✅ writers-scripted-tempo	completed	12	0ms	ok	0
✅ cancel-mid-step	cancelled	7	0ms	skipped	0

Full trace: world-sim.txt

[github-actions]

Framework	Flow route	Step reg.	Framework output
hono	200.9 KiB (±0)	40.3 KiB (±0)	1.76 MiB (+7 B)
nextjs-turbopack	206.3 KiB (±0)	439 B (±0)	763.1 KiB (+7 B)

About these numbers

Sizes are gzip; parentheses show the change against main.
Flow route and Step reg. gate this job, on raw bytes rather than the gzip shown, at max(2%, 50.0 KiB). Framework output is informational.

db061c6 · run

[github-actions]

Backport PR opened against stable: #3827. Merge conflicts were resolved by AI — please review carefully. (backport job run)

[AndrewBarba]

Description

world-local creates a shutdown AbortController, but the controller was only connected to delivery delays and retry backoffs. An HTTP delivery with disabled transport timeouts therefore remained active when the World closed, and undici's graceful Agent.close() waited indefinitely for that request to finish.

Pass the existing close signal to both HTTP transports. Closing the World now aborts its active delivery requests before releasing the transport pool, while preserving graceful agent cleanup and the durable message for recovery after restart.

This was exposed by vercel/eve#2609, which disables local delivery timeouts to prevent healthy long-running agent turns from being redelivered.

How did you test your changes?

Added a world-local queue regression test with both transport timeouts disabled and a server that accepts but never completes the delivery. The test reports timed-out on main and closes immediately with this change.

• pnpm exec turbo build --filter=@workflow/world-local...
• pnpm --filter @workflow/world-local exec vitest run src/queue.test.ts — 26 passed
• pnpm --filter @workflow/world-local typecheck
• pnpm exec biome check packages/world-local/src/queue.ts packages/world-local/src/queue.test.ts — passed with the two existing complexity warnings

PR Checklist - Required to merge

• 📦 pnpm changeset was run to create a changelog for this PR
• 🔒 DCO sign-off passes (run git commit --signoff on your commits)
• 📝 Ping @vercel/workflow in a comment once the PR is ready, and the above checklist is complete

[AndrewBarba]

@vercel/workflow ready for review.

[changeset-bot]

🦋 Changeset detected

Latest commit: db061c6

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

This PR includes changesets to release 18 packages

Name	Type
@workflow/world-local	Patch
@workflow/cli	Patch
@workflow/core	Patch
@workflow/vitest	Patch
@workflow/web	Patch
@workflow/world-postgres	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/web-shared	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

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

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-nextjs-workflow-webpack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-astro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-express-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-fastify-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-hono-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nestjs-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nitro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nuxt-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-python-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-sveltekit-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-tanstack-start-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-vite-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-docs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-swc-playground	Building	Preview, v0	Aug 26, 2026 8:36pm
workflow-tarballs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-web	Ready	Preview, v0	Aug 26, 2026 8:36pm

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

▲ Vercel Production (8 failed)

python-node (8 failed):

• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S | 🔍 observability
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ | 🔍 observability
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG | 🔍 observability
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE | 🔍 observability
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z | 🔍 observability
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT | 🔍 observability
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW | 🔍 observability
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE | 🔍 observability

🌐 Cross-language Conformance (9 failed)

python (9 failed):

• deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0ZWXYSJK22VDCG6YRXP6Q4B
• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE

vercel-multi-region (1 failed)

nextjs-turbopack (1 failed):

• multi-region (world-vercel) hooks on non-iad1 runs hook created by a sfo1 run resolves by token and resumes the run

⚠️ 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.

• deploymentId: 'latest' is a no-op in non-Vercel worlds (nitro)
• hookWithSleepFinalStepWorkflow - step only on final payload (nextjs-webpack)
• hookWorkflow (vite)
• 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.

34 infra events

• cold-start-warmup · suite warmup (python) · at 20:37:39Z · abandoned wrun_41M0ZWJ7WC0GM60ZYBBV2EBQD7 · (+7 more)
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1214
• run-pickup-stall · sleepingWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1213
• run-pickup-stall · nullByteWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH80GVRAN0AWJ7YQ6MY
• run-pickup-stall · promiseAllWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWGY0GJMHCXMPNX6S92S
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWSR0GP3W2DTFB1K69G6
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:38:28Z · abandoned wrun_41M0ZWPVWH0GHX1S11MM5REDP6
• run-pickup-stall · sleepingWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRH0GWH567ZD71WNDMP
• run-pickup-stall · nullByteWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRV0GYJ9PNYHYS89384
• run-pickup-stall · promiseAllWorkflow (python) · at 20:38:57Z · abandoned wrun_41M0ZWQR210GYB5TX06QESX365
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQRH80GJW6FHAQ8V97R9Y
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQV270GWF3V8QH1A8TWMJ
• cold-start-warmup · suite warmup (tanstack-start) · at 20:39:32Z · abandoned wrun_01M0ZWRFCR447TPW9VBW47CCSW
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:40:39Z · abandoned wrun_41M0ZWSRM40GTN4NF0CM5BMN4Z
• cold-start-warmup · suite warmup (python) · at 20:40:49Z · abandoned wrun_01M0ZWR0BZGWCSF0604B0QCS6V · (+7 more)
• run-pickup-stall · sleepingWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH26HN0J7P54QFWRCBT
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGXC6S647VGAZRBBDM9
• run-pickup-stall · nullByteWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH4WVZDC8P1N4TTD1M0
• run-pickup-stall · promiseAllWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGYQHTPNF5W7QPC4MRT
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH3465Q0K3EF487NGED
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:41:18Z · abandoned wrun_41M0ZWSWDZ0GQJ7Q4JYSDDHBTC
• run-pickup-stall · promiseAllWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4EWN54KW4THDWD7T8P
• run-pickup-stall · sleepingWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4HPPDBEHP4NVYFDGN5
• run-pickup-stall · nullByteWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4PCAYE9B8P00J4SCJM
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4BX3YXM3R76WC7CEBX
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4JHHTBRP5FD3DY6392
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQRX9WM6Z4GWW3WJP2D
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQY8R1SKMNWJ5YA9TVE
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQZ8VVKD8GBGM62NTDW
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0838BE3N4FNY4W5KSPK6
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0836388GCBWB0RZF60FW
• run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (nextjs-webpack) · at 20:43:55Z · abandoned wrun_01M0ZX0WB1WDKJYXCQT7X2M0B3
• run-pickup-stall · concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (nextjs-webpack) · at 20:44:00Z · abandoned wrun_01M0ZX11CSS1MAQFSQMF187QW0
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:44:04Z · abandoned wrun_01M0ZX15B28M5P8J1N1VPYADWG

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
❌ ▲ Vercel Production	3570	8	742	4320
✅ 💻 Local Development	3922	0	558	4480
✅ 📦 Local Production	3922	0	558	4480
✅ 🐘 Local Postgres	3922	0	558	4480
✅ 🪟 Windows	320	0	0	320
❌ 🌐 Cross-language Conformance	0	9	132	141
✅ vercel-http-transport	817	0	143	960
❌ vercel-multi-region	26	1	0	27
✅ vercel-ws-transport	553	0	87	640
Total	17052	18	2778	19848

Details by Category

❌ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	132	0	28
✅ astro-quickjs	132	0	28
✅ example-node	132	0	28
✅ example-quickjs	132	0	28
✅ express-node	132	0	28
✅ express-quickjs	132	0	28
✅ fastify-node	132	0	28
✅ fastify-quickjs	132	0	28
✅ hono-node	132	0	28
✅ hono-quickjs	132	0	28
✅ nest-node	132	0	28
✅ nest-quickjs	132	0	28
✅ nextjs-turbopack-node	157	0	3
✅ nextjs-turbopack-quickjs	157	0	3
✅ nextjs-webpack-node	157	0	3
✅ nextjs-webpack-quickjs	157	0	3
✅ nitro-node	132	0	28
✅ nitro-quickjs	132	0	28
✅ nuxt-node	132	0	28
✅ nuxt-quickjs	132	0	28
❌ python-node	0	8	152
✅ sveltekit-node	151	0	9
✅ sveltekit-quickjs	151	0	9
✅ tanstack-start-node	132	0	28
✅ tanstack-start-quickjs	132	0	28
✅ vite-node	132	0	28
✅ vite-quickjs	132	0	28

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	160	0	0
✅ nextjs-turbopack-quickjs	160	0	0

❌ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
❌ python	0	9	132

✅ vercel-http-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ hono	132	0	28
✅ nextjs-turbopack	157	0	3
✅ nitro	132	0	28
✅ vite	132	0	28

❌ vercel-multi-region

App	Passed	Failed	Skipped
❌ nextjs-turbopack	26	1	0

✅ vercel-ws-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ nextjs-turbopack	157	0	3
✅ vite	132	0	28

---

📋 View full workflow run

[github-actions]

📊 Workflow Benchmarks

commit db061c6 · Wed, 26 Aug 2026 21:00:08 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1329 (+39%) 🔻	1506 🔴 (+42%) 🔻	1575 🔴 (+43%) 🔻	1643 🔴 (+40%) 🔻	30
TTFS	stream	1061 (+539%) 🔻	1376 🔴 (+30%) 🔻	1420 🔴 (+25%) 🔻	1651 🔴 (+37%) 🔻	30
TTFS	hook + stream	493 (-61%) 💚	1633 🔴 (+22%) 🔻	1659 🔴 (+22%) 🔻	1707 🔴 (-24%) 💚	30
Fan-out TTFS	Promise.all(100 steps)	606 (+30%) 🔻	968 (+30%) 🔻	989 (-42%) 💚	2274 (-50%) 💚	10
Fan-out TTLS	Promise.all(100 steps)	2043 (+12%)	5113 (+23%) 🔻	5536 (+12%)	9647 (-2.8%)	10
STSO	1020 steps (inline)	89 (-14%)	135 (+5.5%)	160 (+8.1%)	217 (-26%) 💚	1019
WO	1020 steps	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	1
CRTT	first chunk (pooled)	110 (+41%) 🔻	148 (+11%)	189 (+12%)	270 (-18%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	125 (+21%)	167 (+31%)	213 (+17%)	312 (-21%)	123 (-24%)	10
size sweep (100/s, 160B-12KB)	132 (+25%)	174 (+7%)	236 (-50%)	356 (-60%)	155 (-32%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	135 (-20%)	1102 (+748%)	3758 (+2206%)	5151 (+787%)	362 (-15%)	3
replay eve-gpt-5.6-sol-2000t (1x)	136 (-1%)	151 (+11%)	199 (+11%)	321 (-59%)	255 (-60%)	2
replay eve-gpt-5.6-sol-2000t (2x)	171 (+29%)	194 (-2%)	377 (+17%)	931 (+63%)	301 (+11%)	3

📈 STSO distribution vs main (inline / queue-hop histograms)

1020 steps (inline)

Cumulative STSO time: main 134890ms → this run 136346ms (Δ +1456ms, +1%)

 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████┃█ main 924 this 869 -55
150-200 ms ██┃ main 76 this 133 +57
200-250 ms ┃ main 4 this 8 +4
250-300 ms ┃ main 5 this 3 -2
300-350 ms ┃ main 1 this 5 +4
350-400 ms ┃ main 1 this 0 -1
650-700 ms ┃ main 1 this 0 -1
700-750 ms ┃ main 2 this 0 -2
750-800 ms ┃ main 1 this 0 -1
800-850 ms ┃ main 2 this 0 -2
1150-1200 ms ┃ main 1 this 0 -1
1200-1250 ms ┃ main 1 this 0 -1

📈 CRTT drill-down vs main (RTT distributions & profiles)

variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▂█▁···· 133.7 (+23%) 124 (+27%) 213 (+17%) 312 (-21%) 3000
sweep ······▂█▂···· 140.1 (-4%) 127 (+25%) 236 (-50%) 356 (-60%) 3000
gw 1x ·····▁▃█▁▁▁▁▁ 397.7 (+245%) 118 (+16%) 3758 (+2206%) 5151 (+787%) 5295
eve 1x ·····▁▄█▁···· 127 (+5%) 118 (+26%) 199 (+11%) 321 (-59%) 5186
eve 2x ·····▁▂█▃▁··· 173.6 (+11%) 145 (+12%) 377 (+17%) 931 (+63%) 7779

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

control █▂▆▃▁▁▃▅▂▅ 125–148ms
sweep ▆▆█▅▆▂▁▅▆▆ 122–153ms
gw 1x ▁▁▁▁▁█▅▂▁▁ 115–1601ms
eve 1x ▂▂▅▅▁▄▇█▄▆ 114–141ms
eve 2x ▁▁▂▁▁▁▂█▃▁ 129–382ms

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

sweep ▃▆█▃▂▂▁ 139–142ms

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

control ▁▇▂▃▅▅▄▁▄█ 33–44ms
sweep ▁▂█▅▆▅▅▆▅▄ 40–56ms
gw 1x ▁▂▂▁█▄▁▂▂▂ 33–80ms
eve 1x ▁▃▁▃▂▄▆▃█▅ 22–27ms
eve 2x ▆▂▂▃▄▁▁▂█▄ 23–31ms

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.}

[github-actions]

Sim World

Simulated world deterministic testing for races. Traces

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

fence=per-spec

scenario	outcome	events	virt	replay	violations
✅ smoke-no-steps	completed	3	0ms	ok	0
✅ smoke-one-step	completed	6	0ms	ok	0
✅ hook-at-step-started	completed	12	0ms	ok	0
✅ hook-at-step-completed	completed	12	0ms	ok	0
✅ hook-at-hook-created	completed	12	0ms	ok	0
✅ deadline-hook-wins	completed	7	1.0h	ok	0
✅ deadline-expires	completed	7	1.0h	ok	0
✅ long-sleep	completed	11	30.0d	ok	0
✅ hook-never-arrives	stalled	3	0ms	skipped	0
✅ step-retries-twice	completed	10	2.0s	ok	0
✅ parallel-steps	completed	9	0ms	ok	0
✅ hook-on-execution-state	completed	12	0ms	ok	0
✅ peek-hook-before-branch	completed	12	0ms	ok	0
✅ peek-hook-after-branch	completed	12	0ms	ok	0
✅ peek-hook-at-registration	completed	12	0ms	ok	0
✅ race-hook-before-probe	completed	12	0ms	ok	0
✅ race-hook-after-probe	completed	12	0ms	ok	0
✅ race-duplicate-delivery	completed	13	0ms	ok	0
✅ attr-hook-before-step	completed	11	0ms	ok	0
✅ attr-hook-after-step	completed	11	0ms	ok	0
✅ attr-from-step-body	completed	13	0ms	ok	0
✅ fork-hook-after-timeout	completed	14	1.0m	ok	0
✅ fork-hook-before-timeout	completed	14	1.0m	ok	0
✅ count-hook-after-timeout	completed	17	1.0m	ok	0
✅ count-hook-before-timeout	completed	20	1.0m	ok	0
✅ stale-read-step-count-fork	completed	20	1.0m	ok	0
✅ stale-read-equal-step-counts	completed	14	1.0m	ok	0
✅ step-vs-step-fork	completed	12	0ms	ok	0
✅ step-vs-step-fork-fenced	completed	12	0ms	ok	0
✅ fence-catches-benign-direction	completed	12	5ms	ok	0
✅ in-flight-before-decision	completed	17	1.0m	ok	0
❌ in-flight-before-decision-counted	completed	17	1.0m	ok	0
✅ in-flight-after-decision	completed	19	2.0m	ok	0
✅ stale-read-step-count-fork-fenced	completed	20	1.0m	ok	0
✅ fork-hook-wins	completed	13	1.0m	ok	0
✅ fork-timeout-wins	completed	13	1.0m	ok	0
✅ unclaimed-payload-under-fork	completed	17	1.0m	ok	0
✅ claimed-payload-under-fork	completed	17	1.0m	ok	0
✅ writers-independent-step-bodies	completed	12	0ms	ok	0
✅ writers-scripted-tempo	completed	12	0ms	ok	0
✅ cancel-mid-step	cancelled	7	0ms	skipped	0

Full trace: world-sim.txt

[github-actions]

Framework	Flow route	Step reg.	Framework output
hono	200.9 KiB (±0)	40.3 KiB (±0)	1.76 MiB (+7 B)
nextjs-turbopack	206.3 KiB (±0)	439 B (±0)	763.1 KiB (+7 B)

About these numbers

Sizes are gzip; parentheses show the change against main.
Flow route and Step reg. gate this job, on raw bytes rather than the gzip shown, at max(2%, 50.0 KiB). Framework output is informational.

db061c6 · run

[github-actions]

Backport PR opened against stable: #3827. Merge conflicts were resolved by AI — please review carefully. (backport job run)

[AndrewBarba]

Description

world-local creates a shutdown AbortController, but the controller was only connected to delivery delays and retry backoffs. An HTTP delivery with disabled transport timeouts therefore remained active when the World closed, and undici's graceful Agent.close() waited indefinitely for that request to finish.

Pass the existing close signal to both HTTP transports. Closing the World now aborts its active delivery requests before releasing the transport pool, while preserving graceful agent cleanup and the durable message for recovery after restart.

This was exposed by vercel/eve#2609, which disables local delivery timeouts to prevent healthy long-running agent turns from being redelivered.

How did you test your changes?

Added a world-local queue regression test with both transport timeouts disabled and a server that accepts but never completes the delivery. The test reports timed-out on main and closes immediately with this change.

• pnpm exec turbo build --filter=@workflow/world-local...
• pnpm --filter @workflow/world-local exec vitest run src/queue.test.ts — 26 passed
• pnpm --filter @workflow/world-local typecheck
• pnpm exec biome check packages/world-local/src/queue.ts packages/world-local/src/queue.test.ts — passed with the two existing complexity warnings

PR Checklist - Required to merge

• 📦 pnpm changeset was run to create a changelog for this PR
• 🔒 DCO sign-off passes (run git commit --signoff on your commits)
• 📝 Ping @vercel/workflow in a comment once the PR is ready, and the above checklist is complete

[AndrewBarba]

@vercel/workflow ready for review.

[changeset-bot]

🦋 Changeset detected

Latest commit: db061c6

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

This PR includes changesets to release 18 packages

Name	Type
@workflow/world-local	Patch
@workflow/cli	Patch
@workflow/core	Patch
@workflow/vitest	Patch
@workflow/web	Patch
@workflow/world-postgres	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/web-shared	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

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

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-nextjs-workflow-webpack	Ready	Preview, v0	Aug 26, 2026 8:36pm
example-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-astro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-express-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-fastify-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-hono-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nestjs-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nitro-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-nuxt-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-python-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-sveltekit-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-tanstack-start-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workbench-vite-workflow	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-docs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-swc-playground	Building	Preview, v0	Aug 26, 2026 8:36pm
workflow-tarballs	Ready	Preview, v0	Aug 26, 2026 8:36pm
workflow-web	Ready	Preview, v0	Aug 26, 2026 8:36pm

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

▲ Vercel Production (8 failed)

python-node (8 failed):

• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S | 🔍 observability
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ | 🔍 observability
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG | 🔍 observability
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE | 🔍 observability
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z | 🔍 observability
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT | 🔍 observability
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW | 🔍 observability
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE | 🔍 observability

🌐 Cross-language Conformance (9 failed)

python (9 failed):

• deploymentId: 'latest' is a no-op in non-Vercel worlds | wrun_01M0ZWXYSJK22VDCG6YRXP6Q4B
• promiseAllWorkflow | wrun_41M0ZWKMC20GZRB79Y2H0G880S
• sleepingWorkflow | wrun_41M0ZWMBYF0GKC9T5SBV5RAAMZ
• parallelSleepWorkflow | wrun_41M0ZWMC950GMMD63PVABGE9TG
• nullByteWorkflow | wrun_41M0ZWMJSG0GXGYYR8P1K58BTE
• cancelRun - cancelling a running workflow | wrun_41M0ZWSDB50GTT56JH3992183Z
• cancelRun via CLI - cancelling a running workflow | wrun_41M0ZWSGGA0GNM56HTY6WVWJBT
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M0ZWSR9E0GSHZQX17RCTZFSW
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M0ZWTDKR0GY6QQ3VBAB6X1PE

vercel-multi-region (1 failed)

nextjs-turbopack (1 failed):

• multi-region (world-vercel) hooks on non-iad1 runs hook created by a sfo1 run resolves by token and resumes the run

⚠️ 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.

• deploymentId: 'latest' is a no-op in non-Vercel worlds (nitro)
• hookWithSleepFinalStepWorkflow - step only on final payload (nextjs-webpack)
• hookWorkflow (vite)
• 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.

34 infra events

• cold-start-warmup · suite warmup (python) · at 20:37:39Z · abandoned wrun_41M0ZWJ7WC0GM60ZYBBV2EBQD7 · (+7 more)
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1214
• run-pickup-stall · sleepingWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH40GTDXN3JHDQB1213
• run-pickup-stall · nullByteWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWH80GVRAN0AWJ7YQ6MY
• run-pickup-stall · promiseAllWorkflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWGY0GJMHCXMPNX6S92S
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:37:56Z · abandoned wrun_41M0ZWNWSR0GP3W2DTFB1K69G6
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:38:28Z · abandoned wrun_41M0ZWPVWH0GHX1S11MM5REDP6
• run-pickup-stall · sleepingWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRH0GWH567ZD71WNDMP
• run-pickup-stall · nullByteWorkflow (python) · at 20:38:56Z · abandoned wrun_41M0ZWQQRV0GYJ9PNYHYS89384
• run-pickup-stall · promiseAllWorkflow (python) · at 20:38:57Z · abandoned wrun_41M0ZWQR210GYB5TX06QESX365
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQRH80GJW6FHAQ8V97R9Y
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:39:01Z · abandoned wrun_41M0ZWQV270GWF3V8QH1A8TWMJ
• cold-start-warmup · suite warmup (tanstack-start) · at 20:39:32Z · abandoned wrun_01M0ZWRFCR447TPW9VBW47CCSW
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:40:39Z · abandoned wrun_41M0ZWSRM40GTN4NF0CM5BMN4Z
• cold-start-warmup · suite warmup (python) · at 20:40:49Z · abandoned wrun_01M0ZWR0BZGWCSF0604B0QCS6V · (+7 more)
• run-pickup-stall · sleepingWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH26HN0J7P54QFWRCBT
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGXC6S647VGAZRBBDM9
• run-pickup-stall · nullByteWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH4WVZDC8P1N4TTD1M0
• run-pickup-stall · promiseAllWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNGYQHTPNF5W7QPC4MRT
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:41:04Z · abandoned wrun_01M0ZWVNH3465Q0K3EF487NGED
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:41:18Z · abandoned wrun_41M0ZWSWDZ0GQJ7Q4JYSDDHBTC
• run-pickup-stall · promiseAllWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4EWN54KW4THDWD7T8P
• run-pickup-stall · sleepingWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4HPPDBEHP4NVYFDGN5
• run-pickup-stall · nullByteWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4PCAYE9B8P00J4SCJM
• run-pickup-stall · deploymentId: 'latest' is a no-op in non-Vercel worlds (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4BX3YXM3R76WC7CEBX
• run-pickup-stall · parallelSleepWorkflow (python) · at 20:42:04Z · abandoned wrun_01M0ZWXG4JHHTBRP5FD3DY6392
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQRX9WM6Z4GWW3WJP2D
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQY8R1SKMNWJ5YA9TVE
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:43:04Z · abandoned wrun_01M0ZWZAQZ8VVKD8GBGM62NTDW
• run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0838BE3N4FNY4W5KSPK6
• run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:43:34Z · abandoned wrun_01M0ZX0836388GCBWB0RZF60FW
• run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (nextjs-webpack) · at 20:43:55Z · abandoned wrun_01M0ZX0WB1WDKJYXCQT7X2M0B3
• run-pickup-stall · concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (nextjs-webpack) · at 20:44:00Z · abandoned wrun_01M0ZX11CSS1MAQFSQMF187QW0
• run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:44:04Z · abandoned wrun_01M0ZX15B28M5P8J1N1VPYADWG

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
❌ ▲ Vercel Production	3570	8	742	4320
✅ 💻 Local Development	3922	0	558	4480
✅ 📦 Local Production	3922	0	558	4480
✅ 🐘 Local Postgres	3922	0	558	4480
✅ 🪟 Windows	320	0	0	320
❌ 🌐 Cross-language Conformance	0	9	132	141
✅ vercel-http-transport	817	0	143	960
❌ vercel-multi-region	26	1	0	27
✅ vercel-ws-transport	553	0	87	640
Total	17052	18	2778	19848

Details by Category

❌ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	132	0	28
✅ astro-quickjs	132	0	28
✅ example-node	132	0	28
✅ example-quickjs	132	0	28
✅ express-node	132	0	28
✅ express-quickjs	132	0	28
✅ fastify-node	132	0	28
✅ fastify-quickjs	132	0	28
✅ hono-node	132	0	28
✅ hono-quickjs	132	0	28
✅ nest-node	132	0	28
✅ nest-quickjs	132	0	28
✅ nextjs-turbopack-node	157	0	3
✅ nextjs-turbopack-quickjs	157	0	3
✅ nextjs-webpack-node	157	0	3
✅ nextjs-webpack-quickjs	157	0	3
✅ nitro-node	132	0	28
✅ nitro-quickjs	132	0	28
✅ nuxt-node	132	0	28
✅ nuxt-quickjs	132	0	28
❌ python-node	0	8	152
✅ sveltekit-node	151	0	9
✅ sveltekit-quickjs	151	0	9
✅ tanstack-start-node	132	0	28
✅ tanstack-start-quickjs	132	0	28
✅ vite-node	132	0	28
✅ vite-quickjs	132	0	28

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable-node	134	0	26
✅ astro-stable-quickjs	134	0	26
✅ express-stable-node	134	0	26
✅ express-stable-quickjs	134	0	26
✅ fastify-stable-node	134	0	26
✅ fastify-stable-quickjs	134	0	26
✅ hono-stable-node	134	0	26
✅ hono-stable-quickjs	134	0	26
✅ nest-stable-node	134	0	26
✅ nest-stable-quickjs	134	0	26
✅ nextjs-turbopack-canary-node	141	0	19
✅ nextjs-turbopack-canary-quickjs	141	0	19
✅ nextjs-turbopack-stable-node	160	0	0
✅ nextjs-turbopack-stable-quickjs	160	0	0
✅ nextjs-webpack-canary-node	141	0	19
✅ nextjs-webpack-canary-quickjs	141	0	19
✅ nextjs-webpack-stable-node	160	0	0
✅ nextjs-webpack-stable-quickjs	160	0	0
✅ nitro-stable-node	134	0	26
✅ nitro-stable-quickjs	134	0	26
✅ nuxt-stable-node	134	0	26
✅ nuxt-stable-quickjs	134	0	26
✅ sveltekit-stable-node	153	0	7
✅ sveltekit-stable-quickjs	153	0	7
✅ tanstack-start-node	134	0	26
✅ tanstack-start-quickjs	134	0	26
✅ vite-stable-node	134	0	26
✅ vite-stable-quickjs	134	0	26

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	160	0	0
✅ nextjs-turbopack-quickjs	160	0	0

❌ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
❌ python	0	9	132

✅ vercel-http-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ hono	132	0	28
✅ nextjs-turbopack	157	0	3
✅ nitro	132	0	28
✅ vite	132	0	28

❌ vercel-multi-region

App	Passed	Failed	Skipped
❌ nextjs-turbopack	26	1	0

✅ vercel-ws-transport

App	Passed	Failed	Skipped
✅ example	132	0	28
✅ express	132	0	28
✅ nextjs-turbopack	157	0	3
✅ vite	132	0	28

---

📋 View full workflow run

[github-actions]

📊 Workflow Benchmarks

commit db061c6 · Wed, 26 Aug 2026 21:00:08 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1329 (+39%) 🔻	1506 🔴 (+42%) 🔻	1575 🔴 (+43%) 🔻	1643 🔴 (+40%) 🔻	30
TTFS	stream	1061 (+539%) 🔻	1376 🔴 (+30%) 🔻	1420 🔴 (+25%) 🔻	1651 🔴 (+37%) 🔻	30
TTFS	hook + stream	493 (-61%) 💚	1633 🔴 (+22%) 🔻	1659 🔴 (+22%) 🔻	1707 🔴 (-24%) 💚	30
Fan-out TTFS	Promise.all(100 steps)	606 (+30%) 🔻	968 (+30%) 🔻	989 (-42%) 💚	2274 (-50%) 💚	10
Fan-out TTLS	Promise.all(100 steps)	2043 (+12%)	5113 (+23%) 🔻	5536 (+12%)	9647 (-2.8%)	10
STSO	1020 steps (inline)	89 (-14%)	135 (+5.5%)	160 (+8.1%)	217 (-26%) 💚	1019
WO	1020 steps	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	136473 (+1.1%)	1
CRTT	first chunk (pooled)	110 (+41%) 🔻	148 (+11%)	189 (+12%)	270 (-18%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	125 (+21%)	167 (+31%)	213 (+17%)	312 (-21%)	123 (-24%)	10
size sweep (100/s, 160B-12KB)	132 (+25%)	174 (+7%)	236 (-50%)	356 (-60%)	155 (-32%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	135 (-20%)	1102 (+748%)	3758 (+2206%)	5151 (+787%)	362 (-15%)	3
replay eve-gpt-5.6-sol-2000t (1x)	136 (-1%)	151 (+11%)	199 (+11%)	321 (-59%)	255 (-60%)	2
replay eve-gpt-5.6-sol-2000t (2x)	171 (+29%)	194 (-2%)	377 (+17%)	931 (+63%)	301 (+11%)	3

📈 STSO distribution vs main (inline / queue-hop histograms)

1020 steps (inline)

Cumulative STSO time: main 134890ms → this run 136346ms (Δ +1456ms, +1%)

 50-100 ms ┃ main 0 this 1 +1
100-150 ms ██████████████████████┃█ main 924 this 869 -55
150-200 ms ██┃ main 76 this 133 +57
200-250 ms ┃ main 4 this 8 +4
250-300 ms ┃ main 5 this 3 -2
300-350 ms ┃ main 1 this 5 +4
350-400 ms ┃ main 1 this 0 -1
650-700 ms ┃ main 1 this 0 -1
700-750 ms ┃ main 2 this 0 -2
750-800 ms ┃ main 1 this 0 -1
800-850 ms ┃ main 2 this 0 -2
1150-1200 ms ┃ main 1 this 0 -1
1200-1250 ms ┃ main 1 this 0 -1

📈 CRTT drill-down vs main (RTT distributions & profiles)

variant RTT 1ms→5s+ avg p50 p90 p99 n
control ······▂█▁···· 133.7 (+23%) 124 (+27%) 213 (+17%) 312 (-21%) 3000
sweep ······▂█▂···· 140.1 (-4%) 127 (+25%) 236 (-50%) 356 (-60%) 3000
gw 1x ·····▁▃█▁▁▁▁▁ 397.7 (+245%) 118 (+16%) 3758 (+2206%) 5151 (+787%) 5295
eve 1x ·····▁▄█▁···· 127 (+5%) 118 (+26%) 199 (+11%) 321 (-59%) 5186
eve 2x ·····▁▂█▃▁··· 173.6 (+11%) 145 (+12%) 377 (+17%) 931 (+63%) 7779

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

control █▂▆▃▁▁▃▅▂▅ 125–148ms
sweep ▆▆█▅▆▂▁▅▆▆ 122–153ms
gw 1x ▁▁▁▁▁█▅▂▁▁ 115–1601ms
eve 1x ▂▂▅▅▁▄▇█▄▆ 114–141ms
eve 2x ▁▁▂▁▁▁▂█▃▁ 129–382ms

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

sweep ▃▆█▃▂▂▁ 139–142ms

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

control ▁▇▂▃▅▅▄▁▄█ 33–44ms
sweep ▁▂█▅▆▅▅▆▅▄ 40–56ms
gw 1x ▁▂▂▁█▄▁▂▂▂ 33–80ms
eve 1x ▁▃▁▃▂▄▆▃█▅ 22–27ms
eve 2x ▆▂▂▃▄▁▁▂█▄ 23–31ms

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.}

[github-actions]

Sim World

Simulated world deterministic testing for races. Traces

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

fence=per-spec

scenario	outcome	events	virt	replay	violations
✅ smoke-no-steps	completed	3	0ms	ok	0
✅ smoke-one-step	completed	6	0ms	ok	0
✅ hook-at-step-started	completed	12	0ms	ok	0
✅ hook-at-step-completed	completed	12	0ms	ok	0
✅ hook-at-hook-created	completed	12	0ms	ok	0
✅ deadline-hook-wins	completed	7	1.0h	ok	0
✅ deadline-expires	completed	7	1.0h	ok	0
✅ long-sleep	completed	11	30.0d	ok	0
✅ hook-never-arrives	stalled	3	0ms	skipped	0
✅ step-retries-twice	completed	10	2.0s	ok	0
✅ parallel-steps	completed	9	0ms	ok	0
✅ hook-on-execution-state	completed	12	0ms	ok	0
✅ peek-hook-before-branch	completed	12	0ms	ok	0
✅ peek-hook-after-branch	completed	12	0ms	ok	0
✅ peek-hook-at-registration	completed	12	0ms	ok	0
✅ race-hook-before-probe	completed	12	0ms	ok	0
✅ race-hook-after-probe	completed	12	0ms	ok	0
✅ race-duplicate-delivery	completed	13	0ms	ok	0
✅ attr-hook-before-step	completed	11	0ms	ok	0
✅ attr-hook-after-step	completed	11	0ms	ok	0
✅ attr-from-step-body	completed	13	0ms	ok	0
✅ fork-hook-after-timeout	completed	14	1.0m	ok	0
✅ fork-hook-before-timeout	completed	14	1.0m	ok	0
✅ count-hook-after-timeout	completed	17	1.0m	ok	0
✅ count-hook-before-timeout	completed	20	1.0m	ok	0
✅ stale-read-step-count-fork	completed	20	1.0m	ok	0
✅ stale-read-equal-step-counts	completed	14	1.0m	ok	0
✅ step-vs-step-fork	completed	12	0ms	ok	0
✅ step-vs-step-fork-fenced	completed	12	0ms	ok	0
✅ fence-catches-benign-direction	completed	12	5ms	ok	0
✅ in-flight-before-decision	completed	17	1.0m	ok	0
❌ in-flight-before-decision-counted	completed	17	1.0m	ok	0
✅ in-flight-after-decision	completed	19	2.0m	ok	0
✅ stale-read-step-count-fork-fenced	completed	20	1.0m	ok	0
✅ fork-hook-wins	completed	13	1.0m	ok	0
✅ fork-timeout-wins	completed	13	1.0m	ok	0
✅ unclaimed-payload-under-fork	completed	17	1.0m	ok	0
✅ claimed-payload-under-fork	completed	17	1.0m	ok	0
✅ writers-independent-step-bodies	completed	12	0ms	ok	0
✅ writers-scripted-tempo	completed	12	0ms	ok	0
✅ cancel-mid-step	cancelled	7	0ms	skipped	0

Full trace: world-sim.txt

[github-actions]

Framework	Flow route	Step reg.	Framework output
hono	200.9 KiB (±0)	40.3 KiB (±0)	1.76 MiB (+7 B)
nextjs-turbopack	206.3 KiB (±0)	439 B (±0)	763.1 KiB (+7 B)

About these numbers

Sizes are gzip; parentheses show the change against main.
Flow route and Step reg. gate this job, on raw bytes rather than the gzip shown, at max(2%, 50.0 KiB). Framework output is informational.

db061c6 · run

[github-actions]

Backport PR opened against stable: #3827. Merge conflicts were resolved by AI — please review carefully. (backport job run)