[core] Keep step errors whose stack is read-only

[VaguelySerious]

When a step throws, the step executor writes the normalized, source-mapped stack back onto the thrown value before serializing it. Some libraries make stack read-only. postgres.js decorates every query error with Object.defineProperties(err, { stack: { value } }), which turns it into a non-writable data property. Assigning to it throws in strict mode, so the user's error gets replaced by:

TypeError: Cannot assign to read only property 'stack' of object 'PostgresError: relation "embeddings" does not exist'

This happens on every retry attempt and on FatalErrors. The original message only reappears once retries run out, because that path wraps the error in a new FatalError instead of mutating it. I hit this running a RAG example backed by Postgres.

Fix: a setErrorStack helper assigns when it can, redefines the property when it's non-writable but configurable (the postgres.js case), and otherwise leaves the original stack in place. It's used at the three sites that mutate a thrown value's stack: the step retry path, the step fatal path, and the workflow terminal-error path in runtime.ts.

Tests:

• step-executor.test.ts: a step that throws a postgres.js-style error records step_retrying / step_failed with the original message. Both tests failed with the TypeError before the fix.
• set-error-stack.test.ts: writable, postgres.js-style, and non-configurable cases.

🤖 Generated with Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: 65e74c3

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

This PR includes changesets to release 17 packages

Name	Type
@workflow/core	Patch
@workflow/builders	Patch
@workflow/cli	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/vitest	Patch
@workflow/web-shared	Patch
@workflow/web	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch
@workflow/world-vercel	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
example-nextjs-workflow-turbopack	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
example-nextjs-workflow-webpack	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
example-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-astro-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-express-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-fastify-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-hono-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-nestjs-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-nitro-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-nuxt-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-python-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-sveltekit-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-tanstack-start-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workbench-vite-workflow	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workflow-docs	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workflow-swc-playground	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workflow-tarballs	Ready	Preview, v0	Oct 1, 2026 1:28am UTC
workflow-web	Ready	Preview, v0	Oct 1, 2026 1:28am UTC

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

💻 Local Development (1 failed)

sveltekit-stable-node (1 failed):

• createHook({ experimental_force: true }) a run can take over its own earlier hook

⚠️ 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.

• health check (CLI) - workflow health command reports healthy endpoints (nextjs-webpack · local-dev / local / node / canary)

🛠 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.

• run-pickup-stall · runs app-generated source against a registered step (tanstack-start) · at 01:29:29Z · abandoned wrun_01M3TH8XZE4JMRJ4HFGBZQ4QJK
• cold-start-warmup · suite warmup (tanstack-start) · at 01:29:37Z · abandoned wrun_01M3TH8XZE70EME0T1S0SPM1Y4
• run-pickup-stall · fibonacciWorkflow - recursive workflow composition via start() (nextjs-webpack) · at 01:49:29Z · abandoned wrun_01M3TJDJBAKGEPMFX091RH9G1H

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
✅ ▲ Vercel Production	3904	0	875	4779
❌ 💻 Local Development	4405	1	550	4956
✅ 📦 Local Production	4406	0	550	4956
✅ 🐘 Local Postgres	4406	0	550	4956
✅ 🪟 Windows	342	0	12	354
✅ 🌐 Cross-language Conformance	68	0	84	152
✅ dynamic-runs	0	0	0	0
✅ vercel-http-transport	879	0	183	1062
✅ vercel-multi-region	27	0	0	27
✅ vercel-ws-transport	595	0	113	708
Total	19032	1	2917	21950

Details by Category

✅ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	142	0	35
✅ astro-quickjs	142	0	35
✅ example-node	142	0	35
✅ example-quickjs	142	0	35
✅ express-node	142	0	35
✅ express-quickjs	142	0	35
✅ fastify-node	142	0	35
✅ fastify-quickjs	142	0	35
✅ hono-node	142	0	35
✅ hono-quickjs	142	0	35
✅ nest-node	142	0	35
✅ nest-quickjs	142	0	35
✅ nextjs-turbopack-node	169	0	8
✅ nextjs-turbopack-quickjs	169	0	8
✅ nextjs-webpack-node	169	0	8
✅ nextjs-webpack-quickjs	169	0	8
✅ nitro-node	142	0	35
✅ nitro-quickjs	142	0	35
✅ nuxt-node	142	0	35
✅ nuxt-quickjs	142	0	35
✅ python-node	66	0	111
✅ sveltekit-node	161	0	16
✅ sveltekit-quickjs	161	0	16
✅ tanstack-start-node	142	0	35
✅ tanstack-start-quickjs	142	0	35
✅ vite-node	142	0	35
✅ vite-quickjs	142	0	35

❌ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable-node	148	0	29
✅ astro-stable-quickjs	148	0	29
✅ express-stable-node	148	0	29
✅ express-stable-quickjs	148	0	29
✅ fastify-stable-node	148	0	29
✅ fastify-stable-quickjs	148	0	29
✅ hono-stable-node	148	0	29
✅ hono-stable-quickjs	148	0	29
✅ nest-stable-node	148	0	29
✅ nest-stable-quickjs	148	0	29
✅ nextjs-turbopack-canary-node	176	0	1
✅ nextjs-turbopack-canary-quickjs	176	0	1
✅ nextjs-turbopack-stable-node	176	0	1
✅ nextjs-turbopack-stable-quickjs	176	0	1
✅ nextjs-webpack-canary-node	176	0	1
✅ nextjs-webpack-canary-quickjs	176	0	1
✅ nextjs-webpack-stable-node	176	0	1
✅ nextjs-webpack-stable-quickjs	176	0	1
✅ nitro-stable-node	148	0	29
✅ nitro-stable-quickjs	148	0	29
✅ nuxt-stable-node	148	0	29
✅ nuxt-stable-quickjs	148	0	29
❌ sveltekit-stable-node	166	1	10
✅ sveltekit-stable-quickjs	167	0	10
✅ tanstack-start-node	148	0	29
✅ tanstack-start-quickjs	148	0	29
✅ vite-stable-node	148	0	29
✅ vite-stable-quickjs	148	0	29

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable-node	148	0	29
✅ astro-stable-quickjs	148	0	29
✅ express-stable-node	148	0	29
✅ express-stable-quickjs	148	0	29
✅ fastify-stable-node	148	0	29
✅ fastify-stable-quickjs	148	0	29
✅ hono-stable-node	148	0	29
✅ hono-stable-quickjs	148	0	29
✅ nest-stable-node	148	0	29
✅ nest-stable-quickjs	148	0	29
✅ nextjs-turbopack-canary-node	176	0	1
✅ nextjs-turbopack-canary-quickjs	176	0	1
✅ nextjs-turbopack-stable-node	176	0	1
✅ nextjs-turbopack-stable-quickjs	176	0	1
✅ nextjs-webpack-canary-node	176	0	1
✅ nextjs-webpack-canary-quickjs	176	0	1
✅ nextjs-webpack-stable-node	176	0	1
✅ nextjs-webpack-stable-quickjs	176	0	1
✅ nitro-stable-node	148	0	29
✅ nitro-stable-quickjs	148	0	29
✅ nuxt-stable-node	148	0	29
✅ nuxt-stable-quickjs	148	0	29
✅ sveltekit-stable-node	167	0	10
✅ sveltekit-stable-quickjs	167	0	10
✅ tanstack-start-node	148	0	29
✅ tanstack-start-quickjs	148	0	29
✅ vite-stable-node	148	0	29
✅ vite-stable-quickjs	148	0	29

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable-node	148	0	29
✅ astro-stable-quickjs	148	0	29
✅ express-stable-node	148	0	29
✅ express-stable-quickjs	148	0	29
✅ fastify-stable-node	148	0	29
✅ fastify-stable-quickjs	148	0	29
✅ hono-stable-node	148	0	29
✅ hono-stable-quickjs	148	0	29
✅ nest-stable-node	148	0	29
✅ nest-stable-quickjs	148	0	29
✅ nextjs-turbopack-canary-node	176	0	1
✅ nextjs-turbopack-canary-quickjs	176	0	1
✅ nextjs-turbopack-stable-node	176	0	1
✅ nextjs-turbopack-stable-quickjs	176	0	1
✅ nextjs-webpack-canary-node	176	0	1
✅ nextjs-webpack-canary-quickjs	176	0	1
✅ nextjs-webpack-stable-node	176	0	1
✅ nextjs-webpack-stable-quickjs	176	0	1
✅ nitro-stable-node	148	0	29
✅ nitro-stable-quickjs	148	0	29
✅ nuxt-stable-node	148	0	29
✅ nuxt-stable-quickjs	148	0	29
✅ sveltekit-stable-node	167	0	10
✅ sveltekit-stable-quickjs	167	0	10
✅ tanstack-start-node	148	0	29
✅ tanstack-start-quickjs	148	0	29
✅ vite-stable-node	148	0	29
✅ vite-stable-quickjs	148	0	29

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	171	0	6
✅ nextjs-turbopack-quickjs	171	0	6

✅ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
✅ python	68	0	84

✅ dynamic-runs

App	Passed	Failed	Skipped
✅ astro-vercel	0	0	0
✅ example-vercel	0	0	0
✅ express-vercel	0	0	0
✅ fastify-vercel	0	0	0
✅ hono-vercel	0	0	0
✅ nest-vercel	0	0	0
✅ nextjs-turbopack-vercel	0	0	0
✅ nextjs-webpack-vercel	0	0	0
✅ nitro-vercel	0	0	0
✅ nuxt-vercel	0	0	0
✅ sveltekit-vercel	0	0	0
✅ tanstack-start-vercel	0	0	0
✅ vite-vercel	0	0	0

✅ vercel-http-transport

App	Passed	Failed	Skipped
✅ example	142	0	35
✅ express	142	0	35
✅ hono	142	0	35
✅ nextjs-turbopack	169	0	8
✅ nitro	142	0	35
✅ vite	142	0	35

✅ vercel-multi-region

App	Passed	Failed	Skipped
✅ nextjs-turbopack	27	0	0

✅ vercel-ws-transport

App	Passed	Failed	Skipped
✅ example	142	0	35
✅ express	142	0	35
✅ nextjs-turbopack	169	0	8
✅ vite	142	0	35

---

📋 View full workflow run

[github-actions]

📊 Workflow Benchmarks

commit 65e74c3 · Thu, 01 Oct 2026 01:44:28 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	650 (-66%) 💚	2696 🔴 (+31%) 🔻	2809 🔴 (+32%) 🔻	2905 🔴 (+31%) 🔻	30
TTFS	stream	340 (-34%) 💚	2630 🔴 (+15%)	2734 🔴 (+16%) 🔻	2797 🔴 (+2.2%)	30
TTFS	hook + stream	607 (-75%) 💚	2774 🔴 (+3.8%)	2803 🔴 (+0.5%)	2841 🔴 (-1.5%)	30
Fan-out TTFS	Promise.all(100 steps)	555 (+2.6%)	717 (-10%)	730 (-27%) 💚	2809 (+1.0%)	10
Fan-out TTLS	Promise.all(100 steps)	1752 (-37%) 💚	6981 (-24%) 💚	6994 (-24%) 💚	8358 (-10%)	10
STSO	1020 steps (inline)	135 (-6.3%)	179 (-31%) 💚	194 (-46%) 💚	258 (-65%) 💚	1019
WO	1020 steps	177539 (-29%) 💚	177539 (-29%) 💚	177539 (-29%) 💚	177539 (-29%) 💚	1
CRTT	first chunk (pooled)	61 (-9.0%)	94 (-36%) 💚	116 (-29%) 💚	157 (-27%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	80.5 (-32%)	124 (-37%)	165 (-44%)	297 (-49%)	124 (-49%)	10
size sweep (100/s, 160B-12KB)	78.5 (-17%)	129 (-26%)	173 (-29%)	352 (-6%)	150 (-25%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	73 (-49%)	116 (-37%)	135 (-47%)	250 (-66%)	136 (-51%)	3
replay eve-gpt-5.6-sol-2000t (1x)	94 (-39%)	126 (-32%)	156 (-35%)	200 (-67%)	150 (-72%)	2
replay eve-gpt-5.6-sol-2000t (2x)	116 (-5%)	259 (+16%)	690 (+128%)	1148 (+151%)	491 (+65%)	3

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

1020 steps (inline)

Cumulative STSO time: main 249094ms → this run 177033ms (Δ -72061ms, -29%)

  100-150 ms  ┃                         main   3  this  27   +24
  150-200 ms  ███████████░░░░░░░░░░░░┃  main 423  this 913  +490
  200-250 ms  █┃██████                  main 314  this  60  -254
  250-300 ms  ┃██                       main 120  this  17  -103
  300-350 ms  ┃                         main  52  this   2   -50
  350-400 ms  ┃                         main  30  this   0   -30
  400-450 ms  ┃                         main  24  this   0   -24
  450-500 ms  ┃                         main  12  this   0   -12
  500-550 ms  ┃                         main  10  this   0   -10
  550-600 ms  ┃                         main   7  this   0    -7
  600-650 ms  ┃                         main   6  this   0    -6
  650-700 ms  ┃                         main   4  this   0    -4
  700-750 ms  ┃                         main   4  this   0    -4
  750-800 ms  ┃                         main   2  this   0    -2
  800-850 ms  ┃                         main   4  this   0    -4
  850-900 ms  ┃                         main   1  this   0    -1
  900-950 ms  ┃                         main   1  this   0    -1
1200-1250 ms  ┃                         main   2  this   0    -2

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

variant  RTT 1ms→5s+             avg         p50          p90           p99     n
control  ······▆█▁····  109.6 (-33%)  104 (-27%)   165 (-44%)    297 (-49%)  3000
sweep    ······██▁····  109.2 (-25%)  101 (-25%)   173 (-29%)     352 (-6%)  3000
gw 1x    ·····▁██▁····  102.2 (-33%)  100 (-26%)   135 (-47%)    250 (-66%)  5295
eve 1x   ·····▁██▁····  104.9 (-33%)  100 (-28%)   156 (-35%)    200 (-67%)  5186
eve 2x   ·····▁▃█▂▁▁··   177.6 (-3%)  125 (-26%)  690 (+128%)  1148 (+151%)  7779

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

control  █▅▄▁█▁▄▂▁▂  104–120ms
sweep    ▇▅█▂▅▃▃▃▆▁  103–116ms
gw 1x    ▁█▃▂▄▄▄▁▄▆  99–108ms
eve 1x   ▆▁▄▄▂▃▆█▅▁  97–116ms
eve 2x   ▂▁▂▂▁▁▂▅█▇  111–344ms

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

sweep  ▄▅█▇▇▃▁  106–112ms

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

control  ▅▅▄▄█▁▇▇▂▄  27–36ms
sweep    ▄▃█▃█▂▅█▃▁  39–48ms
gw 1x    ▂▆▄▁▅▅▇▆▅█  26–33ms
eve 1x   ▂▁▄▃▅█▁▃█▇  21–24ms
eve 2x   ▅▂▁▂▃▁▂▅██  19–34ms

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]

Sim World

Simulated world deterministic testing for races. Traces

🟠 world-sim scenario book — 1 fail of 42 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
✅ step-vs-timer-early-settlement	completed	8	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	265.9 KiB (±0)	97.2 KiB (±0)	1.99 MiB (+284 B)
nextjs-turbopack	273.3 KiB (±0)	426 B (±0)	981.7 KiB (+99 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.

65e74c3 · run

[karthikscale3]

Reviewed the read-only stack handling across step retry, fatal step, and terminal workflow failure paths. The focused tests and core typecheck pass locally. Looks good.

[github-actions]

No backport to stable for 98442de (AI decision).

This is a genuine correctness fix, but the defect it fixes does not exist on stable. The two mutation sites it patches are main-only: packages/core/src/runtime/step-executor.ts is absent on stable (the step error path there is runtime/step-handler.ts, which serializes normalizedStack into the event data rather than assigning it onto the thrown value), and stable's runtime.ts never assigns terminalError.stack. A grep of packages/core/src on origin/stable finds stack assignments only on freshly constructed errors in serialization.ts and step.ts, which are always writable, so backporting would add a new setErrorStack module with no behavior to fix.

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

98442dea24a392c29adcf843ef1a65c1ed94f32c