# Review by Principal Systems Engineer (Google/Stripe caliber) (Round 1)

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VERDICT: approve

FINDINGS:
- [src/colonyos/server.py:323-339]: Background runs use daemon=True threads with no graceful shutdown — Ctrl-C during an active run could corrupt run state files. Needs signal handler or atexit hook.
- [src/colonyos/server.py:314-317]: Rate limiting prevents concurrent runs but not sequential abuse. No cooldown or per-hour quota.
- [src/colonyos/server.py:200-265]: Config PUT has no optimistic concurrency control (ETag/If-Match). Two browser tabs can silently overwrite each other's edits.
- [web/src/api.ts:17-30]: Auth token in localStorage is XSS-accessible. Acceptable for localhost but should be documented as a known limitation.
- [web/src/components/ArtifactPreview.tsx]: No response caching — every expand/collapse re-fetches content.
- [web/src/__tests__/]: RunLauncher (spends money) and InlineEdit (mutates config) have zero dedicated tests despite being the highest-risk new components.
- [src/colonyos/server.py:371]: Artifact content read with no size limit — a huge file could cause memory pressure.
- [web/src/pages/Config.tsx]: No loading/pending state during inline edit saves, risking user confusion and PUT request races.

SYNTHESIS:
All 22 functional requirements are implemented and all 968 backend + 48 frontend tests pass. The CI fix is correct and minimal — `colonyos[ui]` added to dev extras, web-build job properly configured with SHA-pinned actions. Security posture is strong for a localhost tool: constant-time bearer token auth, path traversal defense-in-depth, sensitive field write-blocking, and proper COLONYOS_WRITE_ENABLED gating. The main operational risks are the unmanaged daemon threads for background runs (data loss on ungraceful shutdown) and the lack of optimistic concurrency on config writes (lost-update races). Neither is a ship-blocker for a single-user localhost tool, but the daemon thread issue should be addressed promptly — it's the kind of thing that corrupts state silently during a late-night debugging session. Test coverage gaps on RunLauncher and InlineEdit are the most notable quality shortcoming. Approving with the expectation that graceful shutdown and the missing component tests land in a fast follow-up.