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[world-local] Retry transport-level queue delivery failures - #2679
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The local queue's delivery loop only retried non-ok HTTP responses. When `fetch()` itself threw — e.g. `TypeError: fetch failed` with an ETIMEDOUT/ ECONNRESET cause, which undici raises when a single-process dev server can't accept all connections under many parallel steps — the exception escaped the retry loop, was logged by the outer catch, and the message was silently dropped. The step never started and was never retried. Wrap the dispatch in a try/catch and treat a transport throw like a failed delivery: back off and retry the same message. Abort (shutdown) and the detached-ArrayBuffer proxy misconfig stay non-retryable. Track the handler delivery attempt separately from the loop counter so a burst of transport timeouts doesn't inflate `x-vqs-message-attempt` and burn the handler's MAX_QUEUE_DELIVERIES budget before its first real execution. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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🦋 Changeset detectedLatest commit: 64488ef The changes in this PR will be included in the next version bump. This PR includes changesets to release 18 packages
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🧪 E2E Test Results✅ All tests passed Summary
Details by Category✅ ▲ Vercel Production
✅ 💻 Local Development
✅ 📦 Local Production
✅ 🐘 Local Postgres
✅ 🪟 Windows
✅ 📋 Other
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📊 Benchmark Results
workflow with no steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) workflow with 1 step💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) workflow with 10 sequential steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Nitro | Express | Next.js (Turbopack) workflow with 25 sequential steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Nitro | Express | Next.js (Turbopack) workflow with 50 sequential steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) Promise.all with 10 concurrent steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) Promise.all with 25 concurrent steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Nitro | Express | Next.js (Turbopack) Promise.all with 50 concurrent steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) Promise.race with 10 concurrent steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Nitro | Express | Next.js (Turbopack) Promise.race with 25 concurrent steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Nitro | Express | Next.js (Turbopack) Promise.race with 50 concurrent steps💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Next.js (Turbopack) | Nitro workflow with 10 sequential data payload steps (10KB)💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) workflow with 25 sequential data payload steps (10KB)💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) workflow with 50 sequential data payload steps (10KB)💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) workflow with 10 concurrent data payload steps (10KB)💻 Local Development
▲ Production (Vercel)
🔍 Observability: Nitro | Express | Next.js (Turbopack) workflow with 25 concurrent data payload steps (10KB)💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) workflow with 50 concurrent data payload steps (10KB)💻 Local Development
▲ Production (Vercel)
🔍 Observability: Nitro | Express | Next.js (Turbopack) Stream Benchmarks(includes TTFB metrics)workflow with stream💻 Local Development
▲ Production (Vercel)
🔍 Observability: Nitro | Express | Next.js (Turbopack) stream pipeline with 5 transform steps (1MB)💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) 10 parallel streams (1MB each)💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) fan-out fan-in 10 streams (1MB each)💻 Local Development
▲ Production (Vercel)
🔍 Observability: Express | Nitro | Next.js (Turbopack) SummaryFastest Framework by WorldWinner determined by most benchmark wins
Fastest World by FrameworkWinner determined by most benchmark wins
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pranaygp
approved these changes
Jun 27, 2026
VaguelySerious
enabled auto-merge (squash)
June 27, 2026 00:28
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Problem
When many steps run in parallel under
world-local(e.g. a workflow that fans out hundreds of"use step"calls viaPromise.all), the local queue dispatches each delivery as afetch()to the single-process dev server. Under that load the server can't accept every connection, so undici raisesTypeError: fetch failedwith anAggregateError [ETIMEDOUT](orECONNRESET) cause —localhostis dual-stack, so both::1and127.0.0.1connect attempts time out and get aggregated.The delivery loop only retried non-ok HTTP responses. A thrown
fetch()escaped the loop entirely, landed in the outer.catch()(logging[local world] Queue operation failed:), and the message was silently dropped — the step never started and was never retried. An HTTP 500 got up to 256 retries; a transport timeout got zero.Fix
Wrap the dispatch in a try/catch and treat a transport-level throw like a failed delivery: back off 5s and retry the same message instead of dropping it. Two cases stay non-retryable:
close()aborted the agent / backoff sleep),The handler delivery attempt (
x-vqs-message-attempt, which the step/flow handlers count againstMAX_QUEUE_DELIVERIES = 48) is now tracked separately from the loop counter, so a burst of transport timeouts can't inflate it and exhaust the handler's delivery budget before its first real execution.Tests
Added regression tests in
queue.test.ts:fetch failed/ETIMEDOUT throw is retried until it clears (was dropped at 1 call before),All existing
world-localqueue tests, including the detached-ArrayBuffer guidance test, still pass.🤖 Generated with Claude Code