fix(server): stop tying codex text-generation temp files to the caller's scope

[juliusmarminge]

Stacked on #2829. Follow-up to #5309 — explains and fixes why branch renaming still didn't work in real builds even though #5309's rename path executed.

Diagnosis (from a live Alpha build containing #5176 + #5309)

Titles generated fine, branches stayed t3code/<hash>. Traces showed the rename fork running and failing in 22ms:

TextGenerationError: Text generation failed in generateBranchName: Failed to write temp file
  [cause]: ENOENT: no such file or directory, open '/var/folders/.../T/t3code-codex-schema-10580-Ahg5y9/a30ebec4bc02'

runCodexJson writes its --output-schema / --output-last-message temp files with makeTempFileScoped, whose Scope requirement leaks to the ambient fiber context (swallowed by the generic S["DecodingServices"] in the return annotation, so it never typechecked as missing). The branch rename fork inherits its context from the launchThread RPC request, whose scope has long since closed by the time the fork runs — and registering a finalizer on a closed scope runs it immediately, deleting the temp directory between creation and write. Hence ENOENT on every branch generation, with #5309's deliberate fallback keeping the temp name.

Title generation kept working because #5176 runs it on the durable effect worker, whose ambient scope stays live — which is exactly why the symptom split (titles ✓ / branches ✗).

Fix

Use unscoped makeTempFile and remove the per-file temp directories in runCodexJson's existing explicit Effect.ensuring(cleanup) instead. Generation is now self-contained regardless of which fiber calls it, and the temp directories (previously left behind by the file-only unlink whenever the scope path wasn't exercised) are cleaned up too.

Testing

• New regression test: generateBranchName succeeds with an explicitly closed ambient Scope provided — fails with the ENOENT error before the fix, passes after.
• Full CodexTextGeneration suite: 18 passed.
• Typecheck clean for t3.

🤖 Generated with Claude Code

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Note

Medium Risk
Changes temp-file lifecycle for all Codex JSON generation paths; behavior is intentional but touches shared CLI orchestration used by commits, PRs, branches, and titles.

Overview
Fixes background generateBranchName failures (ENOENT on temp files) when Codex CLI schema/output temps were created via makeTempFileScoped, so a closed ambient Scope from the launching RPC could reap the directory before the write finished.

writeTempFile now uses unscoped makeTempFile with explicit cleanup: removeTempFileDir on write failure, and runCodexJson’s existing Effect.ensuring removes the full temp directories (not single-file unlinks) on success or failure.

Adds a regression test that generateBranchName succeeds when Scope.Scope is already closed.

^{Reviewed by Cursor Bugbot for commit 0a5b8c1. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Fix codex text-generation temp files to be independent of the caller's scope

• writeTempFile in CodexTextGeneration.ts switches from makeTempFileScoped to makeTempFile, removing the dependency on an ambient Scope being open.
• A new removeTempFileDir helper cleans up the entire temp directory (recursively) on both success and error paths, replacing per-file unlinks that could leave directories behind.
• If output temp file creation fails, the schema temp directory is now explicitly removed to prevent leakage.
• A regression test verifies that generateBranchName works correctly even when the ambient scope is already closed.

^{Macroscope summarized 0a5b8c1.}

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Approvability

Verdict: Approved 0a5b8c1

Straightforward bug fix changing temp file management from scope-based to manual cleanup, addressing an issue where background fibers outlive their launching scope. The author is the primary contributor to this code, and the fix includes a test case.

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