[Kewe63]

Summary

• Reject linked, hard-linked, and non-regular response-cache entries before reading.
• Publish cache updates through private same-directory temporary files and atomic rename.
• Enforce 0600 for new and rewritten cache entries on POSIX.
• Preserve primary I/O errors and avoid deleting a newer cache entry during read-side cleanup races.
• Add focused coverage for linked entries, permissions, atomic replacement, descriptor cleanup, and replacement races.

Fixes #764

Checklist

• Tests pass (npm test)
• src/schema.json updated if new commands or flags were added — not applicable; no command surface changes
• README.md updated if new top-level commands or categories were added — not applicable; no command surface changes
• Changeset added (.changeset/) — only required for user-facing changes (new commands, flags, bug fixes, breaking changes)

Verification

• npx vitest run src/__tests__/api-cache.test.js — 14 passed
• Impacted response-cache/API suites — 6 files, 395 passed
• Production-boundary synthetic PoC — 8 passed, including under umask 077
• npm run lint — passed
• npm run pretest — passed
• git diff --check — passed

A full-suite attempt was terminated by the local environment during concurrent Vitest execution. The only failures observed before termination were existing feedback fixture timeouts that reproduce unchanged on the base revision; the focused and impacted suites for this patch are green.

[nansen-pr-reviewer]

nansen-pr-reviewer summary

The change hardens cache reads against symlinks and non-regular files and makes cache writes atomic with restrictive file modes. The implementation is covered by focused tests and includes the required changeset; no clear correctness or security defect was identified.

Deterministic check: success — No issues found

Risk: 3/5 (Elevated)

✅ Auto-approved — Deterministic gates passed: severity thresholds met, recommendation "approve", risk level 3/5 within threshold 3.

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Token usage: 32,283 input, 2,258 output, 5,299 cache read | Usage Guide

Cooldown: for the next 10 minutes (counting from when this review finished), new pushes to this PR will not trigger another review — the next push after the window expires will. Need a fresh review sooner? Comment @nansen-pr-reviewer[bot] re-review.

[nansen-pr-reviewer]

✅ Auto-approved by Nansen review

Deterministic gates passed: severity thresholds met, recommendation "approve", risk level 3/5 within threshold 3.

• The deterministic severity check passed: No issues found
• Risk level 3/5 (Elevated)
• The model recommended: approve

Approval was decided by deterministic gates, not by the model. The model's recommendation can block auto-approval but never cause it.