Behind the new `OPENCODE_TRANSIENT_FAILOVER_BACKOFF` flag (default off), after two consecutive transient upstream failures the opencode rotation pauses before each later account (1.5s, 3s, 6s, capped at 10s per request) instead of hammering the upstream.
Maintainer rework before merge (kept the idea, no default behavior change):
- The pause honors the client abort signal (no dispatch after a disconnect), the failed attempt's body is cancelled before sleeping, `transientRetryDelayMs` now uses its arguments, and the sleep is injectable so the tests run without real timers.
Validated first on the combined board of all 38 PRs of this batch (10 merged as-is, 28 after the maintainer rework) on top of release/v3.8.51 c0f92ec: typecheck:core, check:open-sse-typecheck and check:dashboard-typecheck clean; ESLint clean on every changed file; file-size (rebaselined for the combined growth), complexity, cognitive-complexity, changelog-integrity, docs-counts, docs-sync, migration-numbering and i18n new-key gates green; 735 focused node:test cases with the only batch-caused failure (a flag-count assertion) fixed. Then re-validated alone on the fresh release tip right before this merge: ESLint on the changed files, typecheck:core, check:open-sse-typecheck, the file-size/complexity/changelog gates and this PR's own tests.
Thanks @maxmad64bis!
Reconciled and merged. This branch was stacked on #12941, which has since landed, so it read as 1484 additions across 16 files and CONFLICTING. I merged the current `release/v3.8.51` into it rather than rewriting your branch: `open-sse/executors/opencode.ts` conflicted in six places where your side was a strict superset of the squashed #12941, and the tip had touched that file through nothing but #12941, so your side was taken whole. The PR now reads as its real 12 files, +839/-25.
The change itself is right: a flapping upstream 5xx aborting the whole agentic chain is exactly the case where rotating to the next healthy account is safe, and keeping it a separate arm from the 400-empty branch matters because that one has to clone-read the body while this one never touches it. Threading `correlationId` through so interleaved requests stay attributable — and never fabricating one when absent — is the right discipline.
Both geo-block regression suites pass alongside the new ones (43/43 across the five opencode test files), which is what proves the conflict resolution preserved #12941's behaviour.
I also tightened the batch's file-size rebaseline here: `src/sse/handlers/chat.ts` needed no bump at all (it lands at 2452, under its existing 2458 freeze) and `open-sse/executors/base.ts` needed only your +2. An earlier measurement had included a local prettier reformat that is not part of this branch.
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Validated in one consolidated worktree cut from `release/v3.8.51`, boarded together with the rest of this batch — zero conflicts between them.
- `typecheck:core` clean; `check:changelog-integrity` OK
- complexity 2799 / baseline 3218 and cognitive-complexity 1265 / baseline 1437 — both under baseline
- 86 focused assertions green across the batch's 10 unit test files, plus 16/16 on the v1 plugin option schema and 16/16 on the v2 option tests
- `check-file-size` rebaselined for this batch's real growth (annotation `_rebaseline_2026_09_11_mergebatch_v3851_maxmad_opencode`, landed on #13141). `open-sse/utils/stream.ts` was deliberately left frozen: it is already 3115 > 3098 on the pure tip with zero contribution from this batch.
⚠️ base-red inherited: #12732 — `Docs Gates`, `Merge integrity`, `No new ESLint warnings`, `Unit Tests fast-path` and `Fast Quality Gates` all reproduce on the pure `release/v3.8.51` tip (provider count 356 vs the 358 the modules define, SKILL.md drift, and the `stream.ts` freeze above). None of them touch these diffs.
Thanks @maxmad64bis.
