fix(responses): let retryOnReset replace a Codex WebSocket send that died unanswered

[FredAmartey]

Summary

• [Bug]: no SSE fallback after an established Codex WebSocket dies mid-turn (prelude-timeout half resolved) #4191 is about Codex turns that die through the proxy with codex websocket closed before a Responses terminal event (close 1006 ...). Since feat(responses): persist content-free Codex WS upstream stage records (#4191) #4427 and 42988a169 that death carries a content-free stage record and settles as an honest 502, and nothing sends the turn again: once the create frame has left, the WebSocket transport never replays, because the turn may already be running upstream. What was still missing is the fallback for a socket that opens and then dies.
• That is the same unknown state as an HTTP connection that resets before its head, and the repo already has an answer for it. feat(retry): opt-in replay of a pre-response reset for self-contained Responses sends #4942 and fix(responses): gate post-header reset recovery on SSE protocol state #4989 let an operator opt in with providers.<name>.retryOnReset: one replacement per logical request, only for a self-contained body, decided in src/lib/request-resend-gate.ts. This PR asks that gate about a socket that closed or errored under its create frame before any Responses event. Nothing changes for a provider that has not opted in.
• The exchange only records what happened. For a close or a transport error, failStream marks the 502 it already settles with the stage the exchange reached (markCodexWsSocketDeath): pre-header when nothing came back, protocol-prelude when frames arrived but none was a Responses event. Silence keeps its 504 and is never marked. A drop after a relayed event keeps the errored 200 body. A native steering or injection exchange is never marked, because its channel may already have sent continuation frames on that socket and the create frame alone no longer describes the turn.
• The passthrough dispatch asks once, at the end of the recovery loop, beside the SSE row. Every leg above already lets that 502 through, since it is non-replayable. The send budget is checked before the gate, which claims the grant last, so a replacement the request cannot fund leaves the grant unspent. The replacement is one HTTP send, never a second socket, logged the way the two HTTP rows log theirs. It is recorded as connection-reset on the same attempt, next to the dead socket's codexWsStage.
• The replacement's answer is settled by settleOperatorReplacement, the rule fetchWithResetRetry already applied after spending the grant, moved out so both rows share it: a status that invites another send becomes the upstream_reset_replay_refused refusal, and any other failure keeps its status and is marked non-replayable. A replacement that throws settles as the same refusal. The answer then goes round the loop like any other, and the SSE row finds the grant spent.
• reasoningEffortRejectionText now skips a non-replayable answer, as the Console Go and opaque-blob peeks already do. Without that, a spent replacement's 400 effort rejection started a downgrade send, from this row or from the pre-header one.
• Why at the end of the loop and not inside the exchange: the socket dies while fetchWithTransientRetry is still awaiting it, and that helper only charges its sends when it returns. A replacement bought from inside the exchange would read the budget one send short, and the helper would treat the replacement's answer as its own to retry.
• sendAmbiguousReplacement is the SSE row's replacement send moved into a helper, unchanged, so both rows send the same way.
• Docs: structure/transports/responses-wire-shapes.md (the WS contract paragraph, whose "errored SSE body" wording predated the 502 settle, and the stage record note), structure/transports/responses-failover.md (the gate section, and the replay boundary paragraph, which now states one rule: the 504 and a drop after the response started are never replaced, and only the 502 of a socket that closed or errored before any Responses event may be replaced once), server.md (the pre-response paragraph no longer says these statuses are never retried, and the retryOnReset paragraph covers the socket) and the retryOnReset row of providers.md in all eight locales. INV-RESEND-02 needs no change.
• Known gap, not fixed here; fix(responses): stop combo failover once a request has spent its ambiguous replacement #5646 fixes it: a 2xx replacement whose stream then fails with zero output. In a failover combo the preflight projects that terminal into a fresh 503 with no marker, so the combo sends the turn to its next target after the grant was spent. The pre-header and SSE rows have had the same gap since Rework #4942 and #4989 into one ambiguous-resend gate with one grant per request #5342, and this row reaches it the same way. fix(responses): stop combo failover once a request has spent its ambiguous replacement #5646 records a "replacement spent" fact on the shared execution budget, which combo failover and the direct path check. The replay boundary section names the gap and points at fix(responses): stop combo failover once a request has spent its ambiguous replacement #5646. The two PRs merge cleanly in either order; whichever lands second, I will rebase the other and drop that sentence.

Refs #4191

Verification

On dev at fa81e5a2a, the base of this PR, with the pinned Bun 1.4.0 (node_modules/.bin/bun):

• Driven red first: the new tests/responses/ws-ambiguous-resend.test.ts, 16 tests. On untouched dev the file does not load, because it imports the new codexWsSocketDeathStage. With that import and the exchange cases taken out, the seven handler cases for the new behaviour fail there (a 502 where one HTTP replacement should serve the turn, no HTTP send, a 502 where the refusal belongs). Three guard cases pass on both sides by design: no grant, a stored turn and a replacement the budget cannot fund, which leaves the grant claimable. With only the reasoningEffortRejectionText line reverted, the effort case fails: the downgrade fires, opens a second socket and ends in a 502. Swapping the budget and gate checks fails the budget case, and dropping the steering exclusion fails the steering case.
• Pool mode, added in review: three cases where the dead socket was the first account's and the HTTP replacement answers a quota 429, a 503 or an unsupported-model 400. Each pins one socket and one HTTP send, both with the first account's bearer and account id, and nothing under the second account's credentials, so no pool ladder turns the replacement's answer or the dead socket's own 502 into a third send. Removing the marker check from shouldRetryCodexPoolAccountQuota fails the 429 and 503 cases, and removing it from codexPoolAccountModel400Denial fails the 400 case, each by sending with the second account.
• The 37 test files around the change (ws-*, reset replay, replay refusal, resend gate, send budget, upstream retry, passthrough, opaque recovery, effort downgrade, pool 401 refresh) with --isolate, in 12-file batches: 1049 pass, 0 fail.
• Full suite on this head, sliced the way scripts/ci/run-bun-test-batches.sh shards CI since ci: release preflight, separate release outcomes, duration-balanced shards, narrow scope checks #5653 (duration-balanced batches of at most 12 files, bun test --isolate --timeout 60000, CI=true): every batch of shards 1/4 to 4/4, past failing batches, the four shards in parallel on one macOS machine, with a 300 s kill deadline per batch in place of CI's 120 s because the machine was shared. 29978 pass and 2 fail across 1573 files, and no batch timed out. Both failures fail the same way on untouched dev at fa81e5a2a when their batch runs alone: codex-runtime.test.ts (treats missing persisted and resolved versions as the same selection) and the provider-option integration spine, whose last assertion hashes the real ~/.claude before and after the test; another process on this machine writes there during the run, so the hash moves.
• cd docs-site && bun run build: 505 pages.
• bun run typecheck, bun run structure:check, bun run privacy:scan, git diff --check and bun test tests/test-layout.test.ts tests/test-layout-tooling.test.ts tests/ci-workflows/file-size-ratchet.test.ts: passed.

Checklist

• Scope stays focused and avoids unrelated cleanup.
• Docs or release notes were updated when needed.
• Security-sensitive changes were reviewed for secrets, auth, and unsafe defaults.

Review readiness checklist

This PR stays in draft until every box below is ticked. Tick all four boxes once the requirements are met:

• Required local validation passed; commands, results, and any full-suite exception are documented.

• I pushed my PR to a recent dev commit (at most 10 behind; a maintainer may still ask for the exact tip before merge).

• I resolved all correct Codex and CodeRabbit findings.

• My PR is ready for review.

Summary by CodeRabbit

• New Features
  • Providers configured with retryOnReset can replace eligible Codex WebSocket failures that occur after the create request is sent but before the first Responses event. The replacement is sent once over HTTP, subject to existing eligibility and retry limits.
• Bug Fixes
  • Silent connections retain their timeout response, and native steering or injection exchanges are not replaced. Failed or refused replacements do not trigger further sends.
• Documentation
  • Updated configuration and transport references across supported languages to describe the retry behavior and its limitations.

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• scripts/test-layout/layout.json
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• tests/responses/ws-ambiguous-resend.test.ts

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📝 Walkthrough

Walkthrough

A Codex WebSocket close or transport error after the create frame but before a Responses event can now enter the ambiguous resend flow. When the resend grant and send budget permit it, the proxy sends one HTTP replacement. Tests and documentation cover this behavior and its limits.

Changes

Codex WebSocket recovery

Layer / File(s)	Summary
Record pre-response socket deaths src/server/responses/codex-ws-wire.ts, src/server/responses/codex-ws-exchange.ts, src/lib/request-resend-gate.ts	The exchange records the projected failure stage for a socket close or transport error before a Responses event, except when native control is present. The wire module exposes the recorded stage to the recovery path.
Authorize and send one HTTP replacement src/server/responses/passthrough-dispatch.ts, src/lib/upstream-retry.ts, src/server/responses/core-opaque-recovery.ts	The recovery path checks the recorded stage, resend grant, and send budget. It uses a shared HTTP-only replacement helper and settles the replacement response. Non-replayable responses skip the reasoning-effort body peek.
Validate and document recovery tests/responses/ws-ambiguous-resend.test.ts, scripts/test-layout/layout.json, tests/fixtures/test-layout-expected.json, docs-site/src/content/docs/reference/configuration/*, docs-site/src/content/docs/{fr,ja,ko,ru,tr,zh-cn,zh-tw}/reference/configuration/providers.md, structure/transports/responses-*	Tests cover socket-death stages, silence, steering exchanges, resend authorization, replacement failures, and send limits. Documentation describes the one-time HTTP replacement and its restrictions, including that silence remains a 504 and native steering or injection turns are not replaced.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant CodexWebSocket
  participant codexWsExchange
  participant passthroughDispatch
  participant resendGate
  participant HTTPUpstream
  CodexWebSocket->>codexWsExchange: close or transport error before a Responses event
  codexWsExchange->>codexWsExchange: record projected socket-death stage
  passthroughDispatch->>codexWsExchange: read recorded stage
  passthroughDispatch->>resendGate: request resend authorization
  resendGate-->>passthroughDispatch: grant or refusal
  passthroughDispatch->>HTTPUpstream: send one HTTP replacement when granted
  HTTPUpstream-->>passthroughDispatch: replacement response

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Merge Risk: 🟡 Moderate · up to 65938

A replacement that fails before producing output can still cause a combo to send the turn to another target. Resolve or explicitly accept that duplicate-send risk before merging.

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❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 58.82% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 17 functions across 7 files. (3 skipped: …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: allowing retryOnReset to replace an unanswered Codex WebSocket send. It matches the implementation and stated pull request objective.

Full details: Docstring Coverage

Explanation

Docstring coverage is 58.82% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 17 functions across 7 files. (3 skipped: 3 unsupported.)

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Maintainers notified: @lidge-jun @Ingwannu

[lidge-jun]

리뷰 · 우선순위 62 / 80

이 변경은 Codex로 가는 웹소켓이 질문을 보낸 뒤, 답의 첫 조각이 오기 전에 끊길 때를 다룹니다.

지금은 그때 502로 끝나고, 프록시는 같은 질문을 다시 보내지 않습니다. 서버가 이미 답을 만들기 시작했을 수 있어서, 또 보내면 같은 일이 두 번 돌 수 있기 때문입니다.

운영자가 그 제공자에 retryOnReset을 켜 둔 경우에만, 이번 변경은 그 끊김을 "응답이 오기 전에 연결이 끊긴 것"과 같이 봅니다. 그래서 허락된 횟수 안에서 HTTP로 한 번만 다시 보냅니다. 웹소켓을 다시 열지는 않습니다. 아무 응답 없이 시간만 지난 504는 그대로입니다. 답을 받기 시작한 뒤의 끊김도 그대로입니다. 조향이나 주입처럼, 그 소켓으로 이어지는 말이 더 나갔을 수 있는 교환도 다시 보내지 않습니다.

다시 보낸 결과가 또 재시도를 부르는 상태(5xx 등)면 거절로 바꿉니다. 400처럼 이유를 보여 줘야 하는 상태는 그 상태 그대로 두고, 그 답으로 추론 강도를 낮춰 또 보내지는 않습니다. 옵션을 끄면 예전과 같습니다.

src/lib/upstream-retry.ts:453 - 대체가 200이면 "다시 보내지 마" 표시를 붙이지 않고 그대로 돌려줍니다. 그 200 뒤에 이어져야 할 답이 글자 하나 없이 끊기면, 콤보는 그걸 새 5xx로 만들고, 표시가 없는 그 5xx를 보고 다음 대상으로 같은 질문을 또 보냅니다. 한 번 더 보내라는 허락은 이미 쓴 뒤입니다. 작성자가 structure/transports/responses-failover.md:284 에 적어 둔 구멍이고, HTTP 쪽 두 길도 같은 구멍입니다. 이 PR은 웹소켓 길을 그 구멍에 하나 더 연결합니다.

structure/transports/responses-failover.md:294 - "이번 릴리스는 그 상태 코드를 옮기지 않는다"고 한 다음 문장이, 옵션을 켠 제공자는 그 502를 HTTP로 한 번 바꿀 수 있다고 합니다. 502가 그대로인지, 한 번 바뀌는지, 한 문단이 두 가지를 말합니다.

tests/responses/ws-ambiguous-resend.test.ts:205 - 테스트는 직접 계정만 봅니다. 계정 풀에서 HTTP 대체가 나간 뒤 세 번째 전송이 막히는 경우는 이 파일에 없습니다. 원래 502를 막는 검사는 src/server/responses/core-codex-account.ts:231 에 있고, 그 파일은 이번 변경에 없습니다.

메인테이너의 판단이 필요한 지점

빈 200 답이 콤보를 다음 대상으로 보내는 구멍을 이 PR과 같이 둘지, 작성자가 말한 다음 PR(요청 쪽에 "대체를 이미 썼다"를 남기는 일) 다음에 합칠지.

응답 이벤트 전에 소켓이 닫히면 닫힘 코드가 1006이든 정상 종료든 같이 한 번 더 보냅니다. 정상 종료도 포함할지.

너의 추천

옵션 기본값은 꺼짐이라, 켜지 않은 제공자는 동작이 그대로입니다. 콤보 장애 조치를 쓰는 제공자만, 이 PR만 넣으면 "한 번만 다시 보낸다"가 빈 답에서 깨집니다. 콤보를 당장 쓰지 않으면 합쳐도 됩니다. 구조 문서 294행은 합치기 전에 "504와, 답을 받기 시작한 뒤의 끊김은 그대로다. 이벤트 전에 닫힌 502만, 옵션을 켰을 때 HTTP로 한 번 바꾼다"로 고치면 됩니다.

이 댓글은 grok-bot이 작성했습니다

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Actionable comments posted: 1

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Inline comments:
In `@src/lib/upstream-retry.ts`:
- Line 453: Update the `response.ok` path to preserve replacement-grant
provenance through the response body and combo failure projection; when that
replacement stream fails, prevent `passthrough-dispatch` from replaying to
another target. Add a combo regression that verifies the case does not cause a
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• docs-site/src/content/docs/fr/reference/configuration/providers.md
• docs-site/src/content/docs/ja/reference/configuration/providers.md
• docs-site/src/content/docs/ko/reference/configuration/providers.md
• docs-site/src/content/docs/reference/configuration/providers.md
• docs-site/src/content/docs/reference/configuration/server.md
• docs-site/src/content/docs/ru/reference/configuration/providers.md
• docs-site/src/content/docs/tr/reference/configuration/providers.md
• docs-site/src/content/docs/zh-cn/reference/configuration/providers.md
• docs-site/src/content/docs/zh-tw/reference/configuration/providers.md
• scripts/test-layout/layout.json
• src/lib/request-resend-gate.ts
• src/lib/upstream-retry.ts
• src/server/responses/codex-ws-exchange.ts
• src/server/responses/codex-ws-wire.ts
• src/server/responses/core-opaque-recovery.ts
• src/server/responses/passthrough-dispatch.ts
• structure/transports/responses-failover.md
• structure/transports/responses-wire-shapes.md
• tests/fixtures/test-layout-expected.json
• tests/responses/ws-ambiguous-resend.test.ts

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[FredAmartey]

Appreciate you going through this one. The fixes are up as 659387449, rebased onto fa81e5a2a while I was at it.

• You're right that the failover doc paragraph said two things at once. It now states one rule: the 504 and a drop after the response started are never replaced, and only the 502 of a socket that closed or errored before any Responses event can be replaced, once, over HTTP, when the provider has retryOnReset on.
• Pool mode has its own cases now in ws-ambiguous-resend.test.ts. The first account's socket dies, then the HTTP replacement comes back with a quota 429, a 503 or an unsupported-model 400. Each case checks for one socket and one HTTP send, both on the first account, with nothing going out under the second account's credentials. Between them they cover the three pool checks that could make a third send: shouldRetryCodexPoolAccountQuota on the refusal's 429, codexPoolAccountModel400Denial on a kept 400 and the transient rotation on the dead socket's own 502. If I pull the marker check out of the quota or model-400 predicate, the matching cases go red.
• The empty 200 in a combo is what fix(responses): stop combo failover once a request has spent its ambiguous replacement #5646 is for. It records "replacement spent" on the shared execution budget, and the WebSocket row's claim sets that too. The two branches merge cleanly in either order, and whichever lands second I'll rebase to drop the "not covered yet" sentence. If you'd rather not ship this row with that gap open, landing fix(responses): stop combo failover once a request has spent its ambiguous replacement #5646 first closes the window.
• On close codes, I'd keep all of them. Nothing in a close frame before a Responses event tells us whether the turn ran. A 1008 or 1009 means the frame was refused, so the replacement is the right fallback there rather than a duplicate. A 1000 or 1001 straight after the create frame is exactly the ambiguous case: the server went away after taking the turn. The grant still caps it at one send, and closeCode stays in the attempt's stage record, so an operator can see which codes led to a replacement.

The push reset the readiness boxes, so I'll tick them again once the full suite has run on this head.

[lidge-jun]

Carried onto dev in bundle PR #5675 (squash-merged as aed3bb8), rebuilt on current dev as commit 27c7aa2 on the lane branch with a Co-authored-by trailer for you, so the credit stays on the merged commit. Closing this one as superseded. Thank you for the fix.