[VaguelySerious]

(AI) Once an entity's terminal event (step_completed/step_failed, wait_completed, hook_disposed, attr_set; never the run entity) has been consumed in replay, every later event under the same correlation id is inert, whatever its class.

Why. A step invocation that stalled past its queue lease can write a step_started or step_retrying after another invocation recorded the step's outcome, and a hook_received can commit behind the hook's hook_disposed. On main such an event repeats no class the walk has seen, so nothing claims it and the node:vm engine reports Replay could not consume event (CORRUPTED_EVENT_LOG). Now it is skipped like any other straggler. The observability duplicate fold (@workflow/web-shared) and the shared fixtures in @workflow/world/test-support apply the same rule; the fold no longer stops at what used to be a divergence point.

Determinism for existing runs.

• EventsConsumer consults the closed-entity map only after every registered callback declined the event, and only after the existing first-of-class check. Any event a consumer claims, and any repeat already skipped today, is handled exactly as before; a retry sequence (step_started, step_retrying, step_started, step_completed) is all claimed by the still-open step consumer.
• An event that hits the new rule had no consumer left on main either. The only way it could still be claimed is a later consumer registering under the same correlation id, and correlation ids are minted per body call from a monotonic ULID with a kind prefix (step_/wait_/hook_/attr_), so a closed id never gets a second consumer. On main such an event therefore always ended in divergence (directly, or as a stranded parked event once the workflow returned); the change only turns that failure into continued replay. Skipped events do not move the replay clock, as with every other skip.
• Events for other correlation ids are untouched: an unclaimed event for an entity that has not closed still diverges.

QuickJS. The QuickJS engine has no divergence detection. On main it already reads past all three straggler shapes (they only mark a pending op created, or buffer a payload nobody reads), so this change aligns the node:vm engine with what QuickJS already does. No QuickJS change is made here. #4661 also skips post-terminal events inside processEvents, but its per-VM closed set persists across processEvents' fixed-point re-scans, so a re-scan skips a closed step's step_created and leaves the step's pending op unmarked when its terminal was buffered before the VM called it (checked locally: the completed step resurfaces as pending-to-create). Left out for that reason. Remaining pre-existing differences, not changed here: QuickJS advances its clock on every event it reads, including stragglers, and a payload buffered after hook_disposed can still be returned by an await hook written after dispose().

Composes with #4683: that classification already treats a disposed hook as closed and counts other step executors' step_retrying as possibly path-changing. With this rule a post-outcome step event can no longer change a decision (on main it failed the run).

Tests. terminal-inert-replay.test.ts replays the same logs through both engines: start and retry after a completed step, start after a failed step, payload after disposal, wait event after completion, an unchanged retry sequence, and an unrelated entity that still diverges. Against main's EventsConsumer the three node:vm straggler cases fail and QuickJS passes. Plus EventsConsumer unit tests and the updated shared fixtures.

Extracted from #4661.

🤖 Generated with Claude Code

[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 9, 2026 9:16pm UTC
example-nextjs-workflow-webpack	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
example-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-astro-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-express-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-fastify-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-hono-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-nestjs-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-nitro-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-nuxt-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-python-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-sveltekit-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-tanstack-start-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workbench-vite-workflow	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workflow-docs	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workflow-swc-playground	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workflow-tarballs	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC
workflow-web	Ready	Preview, v0	Oct 9, 2026 9:16pm UTC

[changeset-bot]

🦋 Changeset detected

Latest commit: 9ba1eb8

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/web-shared	Patch
@workflow/builders	Patch
@workflow/cli	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/vitest	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

[github-actions]

📊 Workflow Benchmarks

commit 9ba1eb8 · Fri, 09 Oct 2026 21:23:42 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1867 (+480%) 🔻	2202 🔴 (+46%) 🔻	2223 🔴 (+41%) 🔻	2297 🔴 (+34%) 🔻	30
TTFS	stream	1823 (+411%) 🔻	2135 🔴 (+45%) 🔻	2181 🔴 (+45%) 🔻	2240 🔴 (+31%) 🔻	30
TTFS	hook + stream	1829 (+174%) 🔻	2516 🔴 (+50%) 🔻	2569 🔴 (+49%) 🔻	4892 🔴 (+159%) 🔻	30
Fan-out TTFS	Promise.all(100 steps)	495 (-11%)	1190 (+26%) 🔻	1220 (+17%) 🔻	2306 (+32%) 🔻	10
Fan-out TTLS	Promise.all(100 steps)	2068 (-11%)	4034 (-6.4%)	4382 (-2.9%)	7491 (+19%) 🔻	10
STSO	1020 steps (inline)	68 (-19%) 💚	106 (-24%) 💚	122 (-31%) 💚	159 (-59%) 💚	1019
WO	1020 steps	106294 (-24%) 💚	106294 (-24%) 💚	106294 (-24%) 💚	106294 (-24%) 💚	1

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

1020 steps (inline)

Cumulative STSO time: main 140168ms → this run 105874ms (Δ -34294ms, -24%)

 50-100 ms  █░░░░░░░░░░░░░┃           main   1  this 525  +524
100-150 ms  █████████████┃██████████  main 820  this 478  -342
150-200 ms  ┃███                      main 133  this  13  -120
200-250 ms  ┃                         main  23  this   2   -21
250-300 ms  ┃                         main   7  this   0    -7
300-350 ms  ┃                         main  16  this   1   -15
350-400 ms  ┃                         main   9  this   0    -9
400-450 ms  ┃                         main   3  this   0    -3
450-500 ms  ┃                         main   2  this   0    -2
500-550 ms  ┃                         main   2  this   0    -2
550-600 ms  ┃                         main   1  this   0    -1
700-750 ms  ┃                         main   1  this   0    -1
850-900 ms  ┃                         main   1  this   0    -1

ℹ️ Metric definitions & methodology

_{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.}

_{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)}

_{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}

_{🔴 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. Streaming delivery performance is measured in durabench.}

_{Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.}

[github-actions]

🧪 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.

• a run can take over its own earlier hook (nextjs-webpack · local-dev / local / node / stable)
• a run can take over its own earlier hook (hono · local-prod / local / quickjs / stable)
• hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (python · vercel-prod / vercel / node / production)

🛠 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 21:19:12Z · abandoned wrun_01M4H8H3J4NWNW8C22AX3H94JF
• cold-start-warmup · suite warmup (tanstack-start) · at 21:19:12Z · abandoned wrun_01M4H8H3JAER27Z196NSAGGDAY
• run-pickup-stall · takes a retained token from a finished run without touching its log (nextjs-webpack) · at 21:25:55Z · abandoned wrun_01M4H8XDHQWRYKJ8ZEB18V4V52
• run-pickup-stall · hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (nextjs-webpack) · at 21:25:55Z · abandoned wrun_01M4H8XDHY56TQBHQ4C1C898WT
• run-pickup-stall · a chain of takeovers: each victim ends with HookForceClaimedError, deliveries follow the current owner (nextjs-webpack) · at 21:25:55Z · abandoned wrun_01M4H8XDR15APM2GT5ZJPE8N21

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
✅ ▲ Vercel Production	3982	0	878	4860
✅ 💻 Local Development	4669	0	551	5220
✅ 📦 Local Production	4669	0	551	5220
✅ 🐘 Local Postgres	4669	0	551	5220
✅ 🪟 Windows	348	0	12	360
✅ 🌐 Cross-language Conformance	68	0	87	155
✅ dynamic-runs	0	0	0	0
✅ vercel-http-transport	897	0	183	1080
✅ vercel-multi-region	27	0	0	27
✅ vercel-ws-transport	607	0	113	720
Total	19936	0	2926	22862

Details by Category

✅ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	145	0	35
✅ astro-quickjs	145	0	35
✅ example-node	145	0	35
✅ example-quickjs	145	0	35
✅ express-node	145	0	35
✅ express-quickjs	145	0	35
✅ fastify-node	145	0	35
✅ fastify-quickjs	145	0	35
✅ hono-node	145	0	35
✅ hono-quickjs	145	0	35
✅ nest-node	145	0	35
✅ nest-quickjs	145	0	35
✅ nextjs-turbopack-node	172	0	8
✅ nextjs-turbopack-quickjs	172	0	8
✅ nextjs-webpack-node	172	0	8
✅ nextjs-webpack-quickjs	172	0	8
✅ nitro-node	145	0	35
✅ nitro-quickjs	145	0	35
✅ nuxt-node	145	0	35
✅ nuxt-quickjs	145	0	35
✅ python-node	66	0	114
✅ sveltekit-node	164	0	16
✅ sveltekit-quickjs	164	0	16
✅ tanstack-start-node	145	0	35
✅ tanstack-start-quickjs	145	0	35
✅ vite-node	145	0	35
✅ vite-quickjs	145	0	35

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable-node	151	0	29
✅ astro-stable-quickjs	151	0	29
✅ express-stable-node	151	0	29
✅ express-stable-quickjs	151	0	29
✅ fastify-stable-node	151	0	29
✅ fastify-stable-quickjs	151	0	29
✅ hono-stable-node	151	0	29
✅ hono-stable-quickjs	151	0	29
✅ nest-stable-node	151	0	29
✅ nest-stable-quickjs	151	0	29
✅ nextjs-turbopack-canary-node	179	0	1
✅ nextjs-turbopack-canary-quickjs	179	0	1
✅ nextjs-turbopack-quickjs-snapshot	179	0	1
✅ nextjs-turbopack-stable-node	179	0	1
✅ nextjs-turbopack-stable-quickjs	179	0	1
✅ nextjs-webpack-canary-node	179	0	1
✅ nextjs-webpack-canary-quickjs	179	0	1
✅ nextjs-webpack-stable-node	179	0	1
✅ nextjs-webpack-stable-quickjs	179	0	1
✅ nitro-stable-node	151	0	29
✅ nitro-stable-quickjs	151	0	29
✅ nuxt-stable-node	151	0	29
✅ nuxt-stable-quickjs	151	0	29
✅ sveltekit-stable-node	170	0	10
✅ sveltekit-stable-quickjs	170	0	10
✅ tanstack-start-node	151	0	29
✅ tanstack-start-quickjs	151	0	29
✅ vite-stable-node	151	0	29
✅ vite-stable-quickjs	151	0	29

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable-node	151	0	29
✅ astro-stable-quickjs	151	0	29
✅ express-stable-node	151	0	29
✅ express-stable-quickjs	151	0	29
✅ fastify-stable-node	151	0	29
✅ fastify-stable-quickjs	151	0	29
✅ hono-stable-node	151	0	29
✅ hono-stable-quickjs	151	0	29
✅ nest-stable-node	151	0	29
✅ nest-stable-quickjs	151	0	29
✅ nextjs-turbopack-canary-node	179	0	1
✅ nextjs-turbopack-canary-quickjs	179	0	1
✅ nextjs-turbopack-quickjs-snapshot	179	0	1
✅ nextjs-turbopack-stable-node	179	0	1
✅ nextjs-turbopack-stable-quickjs	179	0	1
✅ nextjs-webpack-canary-node	179	0	1
✅ nextjs-webpack-canary-quickjs	179	0	1
✅ nextjs-webpack-stable-node	179	0	1
✅ nextjs-webpack-stable-quickjs	179	0	1
✅ nitro-stable-node	151	0	29
✅ nitro-stable-quickjs	151	0	29
✅ nuxt-stable-node	151	0	29
✅ nuxt-stable-quickjs	151	0	29
✅ sveltekit-stable-node	170	0	10
✅ sveltekit-stable-quickjs	170	0	10
✅ tanstack-start-node	151	0	29
✅ tanstack-start-quickjs	151	0	29
✅ vite-stable-node	151	0	29
✅ vite-stable-quickjs	151	0	29

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable-node	151	0	29
✅ astro-stable-quickjs	151	0	29
✅ express-stable-node	151	0	29
✅ express-stable-quickjs	151	0	29
✅ fastify-stable-node	151	0	29
✅ fastify-stable-quickjs	151	0	29
✅ hono-stable-node	151	0	29
✅ hono-stable-quickjs	151	0	29
✅ nest-stable-node	151	0	29
✅ nest-stable-quickjs	151	0	29
✅ nextjs-turbopack-canary-node	179	0	1
✅ nextjs-turbopack-canary-quickjs	179	0	1
✅ nextjs-turbopack-quickjs-snapshot	179	0	1
✅ nextjs-turbopack-stable-node	179	0	1
✅ nextjs-turbopack-stable-quickjs	179	0	1
✅ nextjs-webpack-canary-node	179	0	1
✅ nextjs-webpack-canary-quickjs	179	0	1
✅ nextjs-webpack-stable-node	179	0	1
✅ nextjs-webpack-stable-quickjs	179	0	1
✅ nitro-stable-node	151	0	29
✅ nitro-stable-quickjs	151	0	29
✅ nuxt-stable-node	151	0	29
✅ nuxt-stable-quickjs	151	0	29
✅ sveltekit-stable-node	170	0	10
✅ sveltekit-stable-quickjs	170	0	10
✅ tanstack-start-node	151	0	29
✅ tanstack-start-quickjs	151	0	29
✅ vite-stable-node	151	0	29
✅ vite-stable-quickjs	151	0	29

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	174	0	6
✅ nextjs-turbopack-quickjs	174	0	6

✅ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
✅ python	68	0	87

✅ 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	145	0	35
✅ express	145	0	35
✅ hono	145	0	35
✅ nextjs-turbopack	172	0	8
✅ nitro	145	0	35
✅ vite	145	0	35

✅ vercel-multi-region

App	Passed	Failed	Skipped
✅ nextjs-turbopack	27	0	0

✅ vercel-ws-transport

App	Passed	Failed	Skipped
✅ example	145	0	35
✅ express	145	0	35
✅ nextjs-turbopack	172	0	8
✅ vite	145	0	35

---

📋 View full workflow run

[github-actions]

Sim World

Simulated world deterministic testing for races. Traces

🟢 world-sim scenario book — 0 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	267.4 KiB (±0)	95.4 KiB (±0)	1.99 MiB (+490 B)
nextjs-turbopack	274.8 KiB (±0)	426 B (±0)	969.1 KiB (+212 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.

9ba1eb8 · run

[karthikscale3]

AI Review: No blocking issues found. Reviewed and tested commit 9ba1eb8.

Built and packed this SDK into a standalone Next.js 16.3.8 production application on Node.js 24.13.1. With both Node and QuickJS workflow engines using the local World, checked 12 parallel steps, an intentional retry, durable sleep, caught FatalError, hook receipt/disposal, and restart replay. Filesystem audits confirmed completed steps were not executed again.

Created paused runs with the base SDK, stopped the app, and injected late step_started/step_retrying events after a completed step plus hook_received after hook disposal. The base Node SDK rejected this history with CORRUPTED_EVENT_LOG. Restored the identical pre-replay snapshot, upgraded to this PR, and verified that the pending hook resumed, the original hook payload/result stayed intact, and completed-step side effects were not repeated. Also checked the late-event history with QuickJS and passed 105 focused EventsConsumer, terminal-replay and duplicate-classification tests.

CI currently has 164 successful checks and 6 skipped checks. Scope: local World with controlled persisted-history injection; deployed Vercel delivery and performance benchmarks were not tested.

[github-actions]

No backport to stable for cd2f917 (AI decision).

This is a genuine correctness fix (it stops CORRUPTED_EVENT_LOG failures when a straggling writer appends events after an entity's terminal event), but it is built entirely on main-only infrastructure: packages/world/src/event-metadata.ts (classifyEntityEvent, TERMINAL_EVENT_CLASSES, RUN_ENTITY_KEY, entityEventClass), packages/world/src/test-support/duplicate-event-fixtures.ts, and the whole packages/web-shared package are all absent on stable, and stable's events-consumer.ts has none of the seenEventClasses / firstEventTypeOfClass machinery this change extends. Porting it would mean rewriting the fix against a different replay implementation rather than cherry-picking it; if the underlying failure also affects 4.x, it should be fixed there deliberately via workflow_dispatch or a stable-targeted PR.

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

cd2f917e0fdc5d1f5e35d9ef9508e65d8ddd729a