[world-vercel] Honor WORKFLOW_NODE_HTTP on the queue transport by VaguelySerious · Pull Request #4044 · vercel/workflow

VaguelySerious · 2026-09-09T00:36:31Z

What

getQueueDispatcher was the one dispatcher getter in http-client.ts that ignored WORKFLOW_NODE_HTTP. It now goes through resolveDispatcher like every other getter.

-  return config?.dispatcher ?? getDefaultDispatcher();
+  return resolveDispatcher(config, getDefaultDispatcher);

Why the old reasoning was wrong

The comment argued that undefined cannot move the queue client onto node:http (true: QueueClient accepts a dispatcher and no fetch override), so returning it would only drop this package's pool tuning and land the request on undici's global agent.

That is the wrong framing of what the flag buys. The deployments the flag exists for are the ones where the undici copy this package bundles is unusable, and undefined does move the request off that copy: global fetch dispatches through the runtime's own undici instead. On such a deployment the flag rescues every request path except this one, and this one is the path that acknowledges queue messages.

The consequence is not a slow ack, it is an unbounded redelivery loop:

The handler finishes its work and journals its events over node:http.
processMessage then calls acknowledgeMessage, which dispatches through the broken bundled copy and never resolves.
The invocation never returns, so the platform kills it at maxDuration.
A killed invocation never acknowledges, so the queue redelivers the same message (retryAfterSeconds: 5), to the same deployment, and the cycle repeats.

The run's own state says nothing is wrong: every step is completed. This is the shape reported in #3373 ("messages received 27 times, deleted 0", Cannot read private member #u, Next 16 + Turbopack) and, at much larger scale, by a Pro customer who spent nine days at roughly one million maxDuration timeouts per day on the step and flow routes before patching this function locally. Their patched deployment returned 200 in about a second and logged zero timeouts afterwards.

Trade-off

Under the flag the queue send loses this package's pool tuning (8 connections, ~10s keep-alive) and inherits undici's global agent (unlimited connections, 4s keep-alive). That is the correct trade for a flag whose entire premise is that the bundled undici is not usable in this deployment.

The pool cap on this path is a separate problem, fixed independently in the follow-up PR that gives the queue client its own agent and a request deadline. The two PRs touch the same function and will conflict trivially; whichever lands second needs a one-line rebase.

An explicit config.dispatcher still wins over the flag, unchanged, because supplying one is an instruction to use undici.

Follow-up

The clean fix is a fetch override in @vercel/queue, which would let this path move onto node:http with the rest instead of onto a second undici copy. Worth raising there; this change is what we can do from our side today.

Tests

packages/world-vercel/src/http-client.test.ts: the test that asserted the queue client keeps the undici agent under the flag is replaced by two, one per flag state. 36 passed.

🤖 Generated with Claude Code

getQueueDispatcher was the one dispatcher getter that ignored the flag. The reasoning was that `undefined` cannot move the queue client onto node:http (QueueClient takes a dispatcher and no fetch override), so returning it would only drop this package's pool tuning and fall back to undici's global agent. That misses what the flag is actually for. The deployments that need it are the ones where the undici copy *this package bundles* is unusable, and `undefined` does move the request off that copy: global fetch dispatches on the runtime's own undici instead. On such a deployment every other request survives while the queue client keeps dispatching through the broken copy, and an acknowledgeMessage that never resolves means the message is redelivered for as long as the platform keeps killing the invocation holding it. Losing pool tuning is the correct trade under a flag whose premise is that the bundled undici is not usable here. An explicit config.dispatcher still wins. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

changeset-bot · 2026-09-09T00:36:35Z

🦋 Changeset detected

Latest commit: 6ce61db

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

This PR includes changesets to release 17 packages

Name	Type
@workflow/world-vercel	Patch
@workflow/cli	Patch
@workflow/core	Patch
@workflow/web	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/vitest	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 · 2026-09-09T00:36:38Z

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

Project	Deployment	Actions	Updated
example-nextjs-workflow-turbopack	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
example-nextjs-workflow-webpack	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
example-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-astro-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-express-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-fastify-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-hono-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-nestjs-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-nitro-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-nuxt-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-python-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-sveltekit-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-tanstack-start-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workbench-vite-workflow	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workflow-docs	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workflow-swc-playground	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workflow-tarballs	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC
workflow-web	Ready	Preview, v0	Sep 9, 2026 2:25pm UTC

github-actions · 2026-09-09T00:36:47Z

🧪 E2E Test Results

✅ All tests passed

⚠️ Flaky E2E Tests (passed on retry)

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

addTenWorkflow (nextjs-webpack)
addTenWorkflow (nitro)
addTenWorkflow (tanstack-start)
addTenWorkflow (vite)
cancelRun via CLI - cancelling a running workflow (astro)
concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (example)
deploymentId: 'latest' is a no-op in non-Vercel worlds (vite)
stepFunctionAsStartArgWorkflow - step function reference passed as start() argument (nuxt)
utf8StreamWorkflow (vite)

🛠 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.

cold-start-warmup · suite warmup (tanstack-start) · at 14:26:41Z · abandoned wrun_01M238ZTKCD056RPWA6CFQ3TFX
run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (nextjs-webpack) · at 14:33:38Z · abandoned wrun_01M239CY55TFH8F170ZQTP3N7Z
run-pickup-stall · concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (nextjs-webpack) · at 14:33:44Z · abandoned wrun_01M239D4FSB4PR33C9RX35KWGH

E2E Test Summary

Summary

	Passed	Skipped	Total
✅ ▲ Vercel Production	3662	685	4347
✅ 💻 Local Development	3922	586	4508
✅ 📦 Local Production	3922	586	4508
✅ 🐘 Local Postgres	3922	586	4508
✅ 🪟 Windows	320	2	322
✅ 🌐 Cross-language Conformance	68	74	142
✅ vercel-http-transport	823	143	966
✅ vercel-multi-region	27	0	27
✅ vercel-ws-transport	557	87	644
Total	17223	2749	19972

Details by Category

✅ ▲ Vercel Production

App	Passed	Skipped
✅ astro-node	133	28
✅ astro-quickjs	133	28
✅ example-node	133	28
✅ example-quickjs	133	28
✅ express-node	133	28
✅ express-quickjs	133	28
✅ fastify-node	133	28
✅ fastify-quickjs	133	28
✅ hono-node	133	28
✅ hono-quickjs	133	28
✅ nest-node	133	28
✅ nest-quickjs	133	28
✅ nextjs-turbopack-node	158	3
✅ nextjs-turbopack-quickjs	158	3
✅ nextjs-webpack-node	158	3
✅ nextjs-webpack-quickjs	158	3
✅ nitro-node	133	28
✅ nitro-quickjs	133	28
✅ nuxt-node	133	28
✅ nuxt-quickjs	133	28
✅ python-node	66	95
✅ sveltekit-node	152	9
✅ sveltekit-quickjs	152	9
✅ tanstack-start-node	133	28
✅ tanstack-start-quickjs	133	28
✅ vite-node	133	28
✅ vite-quickjs	133	28

✅ 💻 Local Development

App	Passed	Skipped
✅ astro-stable-node	134	27
✅ astro-stable-quickjs	134	27
✅ express-stable-node	134	27
✅ express-stable-quickjs	134	27
✅ fastify-stable-node	134	27
✅ fastify-stable-quickjs	134	27
✅ hono-stable-node	134	27
✅ hono-stable-quickjs	134	27
✅ nest-stable-node	134	27
✅ nest-stable-quickjs	134	27
✅ nextjs-turbopack-canary-node	141	20
✅ nextjs-turbopack-canary-quickjs	141	20
✅ nextjs-turbopack-stable-node	160	1
✅ nextjs-turbopack-stable-quickjs	160	1
✅ nextjs-webpack-canary-node	141	20
✅ nextjs-webpack-canary-quickjs	141	20
✅ nextjs-webpack-stable-node	160	1
✅ nextjs-webpack-stable-quickjs	160	1
✅ nitro-stable-node	134	27
✅ nitro-stable-quickjs	134	27
✅ nuxt-stable-node	134	27
✅ nuxt-stable-quickjs	134	27
✅ sveltekit-stable-node	153	8
✅ sveltekit-stable-quickjs	153	8
✅ tanstack-start-node	134	27
✅ tanstack-start-quickjs	134	27
✅ vite-stable-node	134	27
✅ vite-stable-quickjs	134	27

✅ 📦 Local Production

App	Passed	Skipped
✅ astro-stable-node	134	27
✅ astro-stable-quickjs	134	27
✅ express-stable-node	134	27
✅ express-stable-quickjs	134	27
✅ fastify-stable-node	134	27
✅ fastify-stable-quickjs	134	27
✅ hono-stable-node	134	27
✅ hono-stable-quickjs	134	27
✅ nest-stable-node	134	27
✅ nest-stable-quickjs	134	27
✅ nextjs-turbopack-canary-node	141	20
✅ nextjs-turbopack-canary-quickjs	141	20
✅ nextjs-turbopack-stable-node	160	1
✅ nextjs-turbopack-stable-quickjs	160	1
✅ nextjs-webpack-canary-node	141	20
✅ nextjs-webpack-canary-quickjs	141	20
✅ nextjs-webpack-stable-node	160	1
✅ nextjs-webpack-stable-quickjs	160	1
✅ nitro-stable-node	134	27
✅ nitro-stable-quickjs	134	27
✅ nuxt-stable-node	134	27
✅ nuxt-stable-quickjs	134	27
✅ sveltekit-stable-node	153	8
✅ sveltekit-stable-quickjs	153	8
✅ tanstack-start-node	134	27
✅ tanstack-start-quickjs	134	27
✅ vite-stable-node	134	27
✅ vite-stable-quickjs	134	27

✅ 🐘 Local Postgres

App	Passed	Skipped
✅ astro-stable-node	134	27
✅ astro-stable-quickjs	134	27
✅ express-stable-node	134	27
✅ express-stable-quickjs	134	27
✅ fastify-stable-node	134	27
✅ fastify-stable-quickjs	134	27
✅ hono-stable-node	134	27
✅ hono-stable-quickjs	134	27
✅ nest-stable-node	134	27
✅ nest-stable-quickjs	134	27
✅ nextjs-turbopack-canary-node	141	20
✅ nextjs-turbopack-canary-quickjs	141	20
✅ nextjs-turbopack-stable-node	160	1
✅ nextjs-turbopack-stable-quickjs	160	1
✅ nextjs-webpack-canary-node	141	20
✅ nextjs-webpack-canary-quickjs	141	20
✅ nextjs-webpack-stable-node	160	1
✅ nextjs-webpack-stable-quickjs	160	1
✅ nitro-stable-node	134	27
✅ nitro-stable-quickjs	134	27
✅ nuxt-stable-node	134	27
✅ nuxt-stable-quickjs	134	27
✅ sveltekit-stable-node	153	8
✅ sveltekit-stable-quickjs	153	8
✅ tanstack-start-node	134	27
✅ tanstack-start-quickjs	134	27
✅ vite-stable-node	134	27
✅ vite-stable-quickjs	134	27

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	160	0	1
✅ nextjs-turbopack-quickjs	160	0	1

✅ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
✅ python	68	0	74

✅ vercel-http-transport

App	Passed	Skipped
✅ example	133	28
✅ express	133	28
✅ hono	133	28
✅ nextjs-turbopack	158	3
✅ nitro	133	28
✅ vite	133	28

✅ vercel-multi-region

App	Passed	Failed	Skipped
✅ nextjs-turbopack	27	0	0

✅ vercel-ws-transport

App	Passed	Skipped
✅ example	133	28
✅ express	133	28
✅ nextjs-turbopack	158	3
✅ vite	133	28

📋 View full workflow run

github-actions · 2026-09-09T00:36:52Z

📊 Workflow Benchmarks

commit 6ce61db · Wed, 09 Sep 2026 14:47:11 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	269 (+37%) 🔻	1418 🔴 (+34%) 🔻	1495 🔴 (+33%) 🔻	3382 🔴 (+187%) 🔻	30
TTFS	stream	232 (-76%) 💚	1334 🔴 (+29%) 🔻	1363 🔴 (+27%) 🔻	1463 🔴 (+33%) 🔻	30
TTFS	hook + stream	1481 (+23%) 🔻	1649 🔴 (+24%) 🔻	1659 🔴 (+19%) 🔻	1758 🔴 (+20%) 🔻	30
Fan-out TTFS	Promise.all(100 steps)	651 (+12%)	2133 (+121%) 🔻	2139 (+39%) 🔻	2305 (+38%) 🔻	10
Fan-out TTLS	Promise.all(100 steps)	2057 (+29%) 🔻	4450 (+40%) 🔻	6075 (+65%) 🔻	9631 (+44%) 🔻	10
STSO	1020 steps (inline)	105 (+5.0%)	132 (+2.3%)	150 (+3.4%)	189 (+3.8%)	1019
WO	1020 steps	133120 (+2.3%)	133120 (+2.3%)	133120 (+2.3%)	133120 (+2.3%)	1
CRTT	first chunk (pooled)	64 (+12%)	128 (+39%) 🔻	190 (+42%) 🔻	4347 (+1885%) 🔻	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	98.5 (+37%)	197 (+22%)	285 (+23%)	425 (-49%)	140 (+8%)	10
size sweep (100/s, 160B-12KB)	96.5 (+17%)	214 (+38%)	281 (+34%)	4309 (+764%)	166 (+31%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	71 (-47%)	148 (+10%)	192 (+1%)	796 (+104%)	215 (-15%)	3
replay eve-gpt-5.6-sol-2000t (1x)	110 (+25%)	136 (+18%)	183 (+25%)	373 (+15%)	338 (+3%)	2
replay eve-gpt-5.6-sol-2000t (2x)	88 (-1%)	239 (+44%)	342 (+43%)	607 (+45%)	248 (+4%)	3

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

1020 steps (inline)

Cumulative STSO time: main 129994ms → this run 131849ms (Δ +1855ms, +1%)

100-150 ms  ██████████████████████┃█  main 947  this 915   -32
150-200 ms  █┃                        main  63  this  96   +33
200-250 ms  ┃                         main   9  this   6    -3
250-300 ms  ┃                         main   0  this   1    +1
300-350 ms  ┃                         main   0  this   1    +1

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

variant  RTT 1ms→5s+              avg         p50         p90           p99     n
control  ······▂█▂····   148.2 (+15%)  130 (+31%)  285 (+23%)    425 (-49%)  3000
sweep    ······▂█▃·▁▂·  433.6 (+248%)  133 (+16%)  281 (+34%)  4309 (+764%)  3000
gw 1x    ·····▁▄█▁▁···   132.5 (+18%)  118 (+17%)   192 (+1%)   796 (+104%)  5295
eve 1x   ·····▁▆█▂▁···   119.5 (+20%)  107 (+22%)  183 (+25%)    373 (+15%)  5186
eve 2x   ·····▁▂█▄▁···   180.8 (+35%)  158 (+34%)  342 (+43%)    607 (+45%)  7779

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

control  █▃▂▂▂▄▁▁▁▁  137–188ms
sweep    █▇▇▆▅▄▃▂▂▁  306–566ms
gw 1x    ▂▂█▂▁▂▂▁▁▁  114–220ms
eve 1x   ▃▁█▆▂▂▅▄▃▂  104–148ms
eve 2x   ▃▁▃▃▁▃▄█▅▁  132–284ms

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

sweep  ▇█▇▆▂▁▃  431–436ms

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

control  ▅▅▁▄▅▄▆▄█▄  37–50ms
sweep    ▁▆▃█▄▃▃▃▅▄  46–70ms
gw 1x    ▅▅█▁▂▃▃▂▂▁  34–51ms
eve 1x   ▅▅█▆▃▁▇▆▄▇  21–26ms
eve 2x   █▄▁▃▁▄▅▂▃▄  22–34ms

📜 Previous results (1)

`0d2778b`

Wed, 09 Sep 2026 01:01:02 GMT · run logs

vercel / nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1227 (+526%) 🔻	1334 🔴 (+26%) 🔻	1372 🔴 (+22%) 🔻	1549 🔴 (+31%) 🔻	30
TTFS	stream	1247 (+31%) 🔻	1314 🔴 (+27%) 🔻	1354 🔴 (+26%) 🔻	1478 🔴 (+34%) 🔻	30
TTFS	hook + stream	1465 (+21%) 🔻	1559 🔴 (+17%) 🔻	1596 🔴 (+15%)	1787 🔴 (+22%) 🔻	30
Fan-out TTFS	Promise.all(100 steps)	614 (+6.0%)	1017 (+5.5%)	1987 (+29%) 🔻	2162 (+30%) 🔻	10
Fan-out TTLS	Promise.all(100 steps)	1870 (+17%) 🔻	2812 (-11%)	4321 (+17%) 🔻	8497 (+27%) 🔻	10
STSO	1020 steps (inline)	92 (-8.0%)	125 (-3.1%)	140 (-3.4%)	213 (+17%) 🔻	1019
WO	1020 steps	124339 (-4.4%)	124339 (-4.4%)	124339 (-4.4%)	124339 (-4.4%)	1
CRTT	first chunk (pooled)	58 (+1.8%)	121 (+32%) 🔻	188 (+40%) 🔻	217 (-0.9%)	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	86.5 (+20%)	178 (+10%)	308 (+33%)	768 (-8%)	123 (-5%)	10
size sweep (100/s, 160B-12KB)	81 (-2%)	147 (-5%)	210 (±0%)	310 (-38%)	117 (-8%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	81 (-40%)	130 (-4%)	171 (-10%)	393 (+1%)	166 (-34%)	3
replay eve-gpt-5.6-sol-2000t (1x)	92 (+5%)	129 (+12%)	165 (+13%)	265 (-18%)	257 (-22%)	2
replay eve-gpt-5.6-sol-2000t (2x)	66 (-26%)	193 (+16%)	290 (+21%)	470 (+12%)	261 (+10%)	3

ℹ️ Metric definitions & methodology

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

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

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

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

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

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

_{Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000t eaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t 6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041}

_{🔴 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 · 2026-09-09T00:40:22Z

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

Full trace: world-sim.txt

github-actions · 2026-09-09T00:41:20Z

Framework	Flow route	Step reg.	Framework output
hono	201.6 KiB (±0)	41.7 KiB (±0)	1.78 MiB (+255 B)
nextjs-turbopack	207.8 KiB (±0)	439 B (±0)	771.6 KiB (-2 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.

6ce61db · run

The queue client is a partial exception to the flag, not a full one: it cannot move to node:http, but it does honor the flag by dispatching through the runtime's own copy of the HTTP client library instead of the copy the World bundles. That distinction is the whole point when the bundled copy is what does not work. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

github-actions · 2026-09-09T17:18:19Z

Backport to stable failed for f83e836 due to a workflow error (backport job run).

This is usually an infrastructure problem (e.g. the configured AI model could not be found, an AI Gateway error, or an opencode crash) rather than a merge conflict. Check the job logs linked above for details.

Once the underlying issue is fixed, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:

f83e8367f43b73e36e5dde9fdd29279dc51c3e09

* fix(world-vercel): honor WORKFLOW_NODE_HTTP on the queue transport getQueueDispatcher was the one dispatcher getter that ignored the flag. The reasoning was that `undefined` cannot move the queue client onto node:http (QueueClient takes a dispatcher and no fetch override), so returning it would only drop this package's pool tuning and fall back to undici's global agent. That misses what the flag is actually for. The deployments that need it are the ones where the undici copy *this package bundles* is unusable, and `undefined` does move the request off that copy: global fetch dispatches on the runtime's own undici instead. On such a deployment every other request survives while the queue client keeps dispatching through the broken copy, and an acknowledgeMessage that never resolves means the message is redelivered for as long as the platform keeps killing the invocation holding it. Losing pool tuning is the correct trade under a flag whose premise is that the bundled undici is not usable here. An explicit config.dispatcher still wins. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> * docs: correct the queue-send note for WORKFLOW_NODE_HTTP The queue client is a partial exception to the flag, not a full one: it cannot move to node:http, but it does honor the flag by dispatching through the runtime's own copy of the HTTP client library instead of the copy the World bundles. That distinction is the whole point when the bundled copy is what does not work. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com> Signed-off-by: Peter Wielander <mittgfu@gmail.com>

github-actions · 2026-09-09T17:35:17Z

Backport PR opened against stable: #4054. Merge conflicts were resolved by AI — please review carefully. (backport job run)

…c-workflow-source * origin/main: (22 commits) feat(streams): add writer session seam (#3832) docs: document WORKFLOW_NODE_HTTP in the v4 World docs (#4050) [world-vercel] Honor WORKFLOW_NODE_HTTP on the queue transport (#4044) feat(streams): add WebSocket capability gate (#3764) fix(world-local): retry JSON reads on Windows (#4051) [core] Add the wake-loop scenario to the event log race repro (#4017) [ci] Cap concurrent Vercel E2E action repo-wide (10 by default) (#4039) Add `Run#getWritable()` for appending to another run's stream (#3972) feat(streams): add WebSocket v1 client protocol contract (#3763) [swc-playground] Update to Next.js v16.3.4 (#4018) [core] Add a retention option to start() (#3787) fix(swc-plugin): register class expressions via an IIFE instead of by name (#3971) [docs] Fix prose typos across v4/v5 docs and the SWC plugin README (#3948) Validate pending changesets in CI so a bad one fails the PR, not the Release job (#3964) Version Packages (beta) (#3919) Classify Workflow stream failures (#3850) Drop the ignored @workflow/world-sim package from the hook_conflict delta changeset (#3963) Add attribute inspection to the CLI (#3950) [core] Settle a hook's awaiter in-process instead of re-invoking, on creation and on conflict (#3938) Use the storage APIs for run detail views (#3944) ...

…transport (#4054) Co-authored-by: Peter Wielander <mittgfu@gmail.com> Co-authored-by: Peter Wielander <peter.wielander@vercel.com>

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VaguelySerious mentioned this pull request Sep 9, 2026

[world-vercel] Bound the queue client's requests #4049

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VaguelySerious marked this pull request as ready for review September 9, 2026 14:28

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karthikscale3 approved these changes Sep 9, 2026

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VaguelySerious merged commit f83e836 into main Sep 9, 2026
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VaguelySerious deleted the peter/queue-flag branch September 9, 2026 17:17

github-actions Bot mentioned this pull request Sep 9, 2026

Version Packages (beta) #4011

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github-actions Bot mentioned this pull request Sep 9, 2026

Backport #4044: [world-vercel] Honor WORKFLOW_NODE_HTTP on the queue transport #4054

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VaguelySerious mentioned this pull request Sep 9, 2026

[ci] Print opencode's server log in the backport job #4056

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Backport #4044: [world-vercel] Honor WORKFLOW_NODE_HTTP on the queue …

4607916

…transport (#4054) Co-authored-by: Peter Wielander <mittgfu@gmail.com> Co-authored-by: Peter Wielander <peter.wielander@vercel.com>

github-actions Bot mentioned this pull request Sep 9, 2026

Version Packages #4060

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[world-vercel] Honor WORKFLOW_NODE_HTTP on the queue transport - #4044

[world-vercel] Honor WORKFLOW_NODE_HTTP on the queue transport#4044
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VaguelySerious commented Sep 9, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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🧪 E2E Test Results

⚠️ Flaky E2E Tests (passed on retry)

🛠 Infra Events (absorbed by the harness)

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📊 Workflow Benchmarks

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