[world-vercel] Bound the queue client's requests by VaguelySerious · Pull Request #4049 · vercel/workflow

VaguelySerious · 2026-09-09T14:22:24Z

What

Gives the @vercel/queue client its own undici agent and a total per-request deadline.

getQueueAgentOptions(): 64 connections (WORKFLOW_VERCEL_QUEUE_CONNECTIONS), explicit 30s headersTimeout / bodyTimeout (WORKFLOW_VERCEL_QUEUE_TIMEOUT_MS).
deadlineInterceptor(): a total deadline armed at dispatch, so it covers time spent waiting for a connection and not just time on the wire.
createQueueDispatcher() / its own pools.queueDispatcher singleton, so the queue no longer shares the control-plane agent.

Why

Two separate gaps, both on this one path.

It has no deadline. Every other request in this package goes through makeRequest or instrumentedFetch, which wrap the call in AbortSignal.timeout(getRequestTimeoutMs()). QueueClient calls global fetch itself and accepts no fetch override, so it cannot be handed one. On main the agents set no headersTimeout either (they deliberately inherit undici's 300s default, see the comment above NODE_HTTP_HEADERS_TIMEOUT_MS), so a stalled acknowledgement had a 300s floor and nothing above it. stable sets 30s explicitly, which is where that number comes from.

Waiting for a connection is not covered by headersTimeout. undici arms that timer only once a request reaches a socket. Sharing BASE_AGENT_OPTIONS.connections (8) with the control-plane paths therefore made invocation concurrency the binding constraint on acknowledging messages, and made the wait grow with backlog depth. Measured against the shipped configuration, 12 concurrent requests through 8 connections against a server that accepts and never answers:

req  0-7    30510ms  UND_ERR_HEADERS_TIMEOUT
req  8-11   61028ms  UND_ERR_HEADERS_TIMEOUT   <- 2x the 30s timeout

The k-th queued request settles at ceil(k / 8) x headersTimeout, confirmed to hold at 80 concurrent. So a transport fault that should surface as one failed ack instead grows without bound, and the loop feeds itself: each invocation the platform kills for exceeding maxDuration leaves its message unacknowledged, the queue redelivers after retryAfterSeconds: 5, and that adds another ack to the same queue. At the shipped 30s, roughly 216 queued acks on one instance's agent is enough to put a request at a Pro plan's 800s cap.

The queue client's shape is the opposite of the control plane's: about two small requests per invocation (one acknowledgeMessage, plus a changeVisibility per renewal interval), so its concurrency tracks how many invocations the instance is serving rather than any per-request fan-out. A shared 8-connection pool is the wrong budget for it.

Three things that did not work

Recorded in the comments so they are not retried:

opts.signal is ignored at the dispatch level. undici's higher-level request / fetch entry points translate a signal before dispatching; injecting one from an interceptor changes nothing. A request given a 2s injected signal still settled at the 60s headersTimeout.
A timer armed in onRequestStart cannot see the wait, because undici raises that callback only once the request reaches a connection. With connections: 1, the second request's onRequestStart fired at 2015ms, after the first had already aborted and freed the slot.
The interceptor must sit inside the RetryAgent. compose() returns a Proxy and RetryAgent.prototype.close reads a private field through this, so composing on the outside leaves a dispatcher that throws Cannot read private member #agent on close(). Inside costs nothing here: every request on this dispatcher is a POST, and RETRY_AGENT_OPTIONS inherits undici's default methods, which never retries POST, so per-attempt and per-request are the same deadline. They would diverge if a retryable method were added.

So the timer is armed in the interceptor and the abort is delivered through the controller onRequestStart hands over. A request whose deadline expires while queued is aborted the instant it reaches a connection, which is what keeps the bound flat: the backlog drains at the deadline rather than at deadline x queue depth.

Tests

packages/world-vercel/src/http-client.test.ts, new queue client transport suite: own dispatcher, connection budget above the shared pool, explicit deadlines, both env overrides with clamping, and the regression itself. That last one drives 6 concurrent requests through connections: 1 at a 5s deadline against a server that never answers and asserts they all settle inside 10s; with no queue-wait bound it would be 30s.

648 tests pass in @workflow/world-vercel.

Notes

Touches the same function as #4044, so the two conflict trivially and whichever lands second needs a one-line rebase. They fix different halves and neither depends on the other: #4044 lets the flag reach this path at all, this one bounds the path whether or not the flag is set.

Both new environment variables are documented in docs/content/docs/v5/configuration/runtime-tuning.mdx.

🤖 Generated with Claude Code

vercel · 2026-09-09T14:22:31Z

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 6:28pm UTC
example-nextjs-workflow-webpack	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
example-workflow	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
workbench-astro-workflow	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
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workbench-fastify-workflow	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
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workbench-nestjs-workflow	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
workbench-nitro-workflow	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
workbench-nuxt-workflow	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
workbench-python-workflow	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
workbench-sveltekit-workflow	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
workbench-tanstack-start-workflow	Ready	Preview, v0	Sep 9, 2026 6:28pm UTC
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1 Skipped Deployment

Project	Deployment	Actions	Updated
workflow-docs	Skipped	v0	Sep 9, 2026 6:28pm UTC

changeset-bot · 2026-09-09T14:22:33Z

🦋 Changeset detected

Latest commit: fb474c7

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

github-actions · 2026-09-09T14:22:47Z

🧪 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.

abortHookOrderingWorkflow [hook-first-hook-first]: hook.then → addEventListener → resumeHook → abort() (nextjs-webpack)
AllInOneService.processNumber - static workflow method using sibling static step methods (sveltekit)
cancelRun via CLI - cancelling a running workflow (hono)
cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
cancelRun via CLI - cancelling a running workflow (nitro)
cancelRun via CLI - cancelling a running workflow (nuxt)
cancelRun via CLI - cancelling a running workflow (sveltekit)
cancelRun via CLI - cancelling a running workflow (vite)
deploymentId: 'latest' is a no-op in non-Vercel worlds (nitro)

🛠 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 18:26:48Z · abandoned wrun_01M23PQGDC0VGA9Y27A342BMY0
run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (nextjs-webpack) · at 18:32:06Z · abandoned wrun_01M23Q1JNS401JXHXT4A03HB98
run-pickup-stall · concurrent hook token conflict - two workflows cannot use the same hook token simultaneously (nextjs-webpack) · at 18:32:07Z · abandoned wrun_01M23Q1KGPQNBT4K905T3DC6NE

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 · 2026-09-09T14:23:23Z

📊 Workflow Benchmarks

commit fb474c7 · Wed, 09 Sep 2026 18:49:18 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	181 (-72%) 💚	1240 🔴 (+12%)	1284 🔴 (+11%)	1654 🔴 (+40%) 🔻	30
TTFS	stream	217 (-7.7%)	1272 🔴 (+19%) 🔻	1300 🔴 (+17%) 🔻	1328 🔴 (+13%)	30
TTFS	hook + stream	1094 (+161%) 🔻	1591 🔴 (+18%) 🔻	1603 🔴 (+16%) 🔻	1789 🔴 (+26%) 🔻	30
Fan-out TTFS	Promise.all(100 steps)	735 (+23%) 🔻	821 (-53%) 💚	827 (-55%) 💚	1215 (-34%) 💚	10
Fan-out TTLS	Promise.all(100 steps)	1600 (-28%) 💚	5623 (+47%) 🔻	6931 (+49%) 🔻	8495 (+50%) 🔻	10
STSO	1020 steps (inline)	109 (+17%) 🔻	149 (+9.6%)	173 (+13%)	270 (+22%) 🔻	1019
WO	1020 steps	143733 (+6.5%)	143733 (+6.5%)	143733 (+6.5%)	143733 (+6.5%)	1
CRTT	first chunk (pooled)	65 (-7.1%)	99 (-42%) 💚	143 (-23%) 💚	201 (+5.2%)	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	94 (+4%)	225 (-10%)	767 (+125%)	1022 (+58%)	160 (-35%)	10
size sweep (100/s, 160B-12KB)	89 (-3%)	181 (-45%)	327 (-38%)	610 (-38%)	157 (-47%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	113 (-39%)	140 (-49%)	241 (-45%)	755 (+1%)	279 (-24%)	3
replay eve-gpt-5.6-sol-2000t (1x)	95.5 (-11%)	141 (-32%)	190 (-70%)	395 (-90%)	286 (-86%)	2
replay eve-gpt-5.6-sol-2000t (2x)	72 (-58%)	294 (-30%)	550 (-6%)	935 (+13%)	432 (+17%)	3

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

1020 steps (inline)

Cumulative STSO time: main 133880ms → this run 143551ms (Δ +9671ms, +7%)

 50-100 ms  ┃                         main   2  this   0    -2
100-150 ms  ████████████████████┃███  main 884  this 774  -110
150-200 ms  ███░┃                     main 118  this 193   +75
200-250 ms  ┃                         main  11  this  39   +28
250-300 ms  ┃                         main   3  this   4    +1
300-350 ms  ┃                         main   0  this   6    +6
350-400 ms  ┃                         main   1  this   2    +1
500-550 ms  ┃                         main   0  this   1    +1

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

variant  RTT 1ms→5s+             avg         p50          p90          p99     n
control  ······▂█▃▁▁··   195.7 (±0%)  136 (-23%)  767 (+125%)  1022 (+58%)  3000
sweep    ······▃█▂▁···  148.6 (-40%)  127 (-37%)   327 (-38%)   610 (-38%)  3000
gw 1x    ·····▁▅█▂▁···  131.4 (-27%)  110 (-24%)   241 (-45%)    755 (+1%)  5295
eve 1x   ·····▁▆█▂▁···  122.5 (-56%)  107 (-25%)   190 (-70%)   395 (-90%)  5186
eve 2x   ·····▁▂█▄▁▁··  208.3 (-21%)  157 (-32%)    550 (-6%)   935 (+13%)  7779

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

control  ▆▃▃▁▁▂▆██▇  140–250ms
sweep    ▇▇▇▇▃▁▁▁▇█  119–171ms
gw 1x    ▃▂▁▃▁▁█▂▃▂  111–202ms
eve 1x   ▁▂▅▅▂▂▅█▇▁  103–151ms
eve 2x   ▁▁▁▂▁▂▄█▆▂  149–378ms

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

sweep  ▁▆▅█▅▃▄  147–151ms

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

control  ▂▅▂▃▄▄▆█▄▁  44–71ms
sweep    ▁▇█▆▄▄▂▅█▃  46–73ms
gw 1x    ▂▃▄▂▂▁█▂▂▂  33–50ms
eve 1x   ▁▃▅▆▅▄▅▇█▃  22–29ms
eve 2x   ▅▂▁▂▃▃▆█▁▇  30–37ms

📜 Previous results (1)

`76088df`

Wed, 09 Sep 2026 14:42:21 GMT · run logs

vercel / nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1037 (+429%) 🔻	1242 🔴 (+18%) 🔻	1264 🔴 (+12%)	1438 🔴 (+22%) 🔻	30
TTFS	stream	212 (-78%) 💚	1208 🔴 (+16%) 🔻	1216 🔴 (+13%)	1276 🔴 (+16%) 🔻	30
TTFS	hook + stream	1406 (+16%) 🔻	1510 🔴 (+13%)	1642 🔴 (+18%) 🔻	1688 🔴 (+15%)	30
Fan-out TTFS	Promise.all(100 steps)	570 (-1.6%)	811 (-16%) 💚	816 (-47%) 💚	2327 (+40%) 🔻	10
Fan-out TTLS	Promise.all(100 steps)	1573 (-1.3%)	8025 (+153%) 🔻	8043 (+119%) 🔻	9151 (+37%) 🔻	10
STSO	1020 steps (inline)	91 (-9.0%)	119 (-7.8%)	135 (-6.9%)	181 (-0.5%)	1019
WO	1020 steps	119430 (-8.2%)	119430 (-8.2%)	119430 (-8.2%)	119430 (-8.2%)	1
CRTT	first chunk (pooled)	47 (-18%) 💚	82 (-11%)	99 (-26%) 💚	781 (+257%) 🔻	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	75.5 (+5%)	132 (-19%)	342 (+48%)	900 (+8%)	124 (-5%)	10
size sweep (100/s, 160B-12KB)	70 (-15%)	123 (-21%)	165 (-21%)	255 (-49%)	104 (-19%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	77 (-43%)	109 (-19%)	124 (-35%)	195 (-50%)	132 (-48%)	3
replay eve-gpt-5.6-sol-2000t (1x)	61.5 (-30%)	109 (-5%)	142 (-3%)	234 (-28%)	153 (-53%)	2
replay eve-gpt-5.6-sol-2000t (2x)	59 (-34%)	185 (+11%)	273 (+14%)	4219 (+909%)	254 (+7%)	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 · 2026-09-09T14:26:25Z

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

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

github-actions · 2026-09-09T18:51:16Z

Backport to stable failed for 2354301 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:

2354301f39d5740b33ffbbb4dc8573108006619a

Signed-off-by: Peter Wielander <mittgfu@gmail.com>

github-actions · 2026-09-09T19:16:43Z

Backport PR opened against stable: #4061. Merge conflicts were resolved by AI — please review carefully. (backport job run)

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chore: trigger CI

fb474c7

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

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VaguelySerious enabled auto-merge (squash) September 9, 2026 18:43

VaguelySerious merged commit 2354301 into main Sep 9, 2026
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VaguelySerious deleted the peter/queue-pool branch September 9, 2026 18:50

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

Version Packages (beta) #4011

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

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Signed-off-by: Peter Wielander <mittgfu@gmail.com>

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Backport #4049: [world-vercel] Bound the queue client's requests #4061

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[world-vercel] Bound the queue client's requests (#4049) (#4061)

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Version Packages #4060

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

[world-vercel] Bound the queue client's requests#4049
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VaguelySerious commented Sep 9, 2026

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Three things that did not work

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🧪 E2E Test Results

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🛠 Infra Events (absorbed by the harness)

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📊 Workflow Benchmarks

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