# Review by Principal Systems Engineer (Google/Stripe caliber) (Round 2)

I now have a complete picture. Here is my review:

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## Principal Systems Engineer Review

### Completeness

- [x] **FR-1 (Intent Classification)**: All four categories (`CODE_CHANGE`, `QUESTION`, `STATUS`, `OUT_OF_SCOPE`) implemented in `RouterCategory` enum with proper classification prompt.
- [x] **FR-2 (Reuse Slack Triage)**: `triage_message()` now delegates to `route_query()` and maps `RouterResult → TriageResult`. Legacy fallback preserved when `triage_scope` is set.
- [x] **FR-3 (Two-Stage Q&A)**: Router classifies (haiku, no tools, $0.05), then `answer_question()` handles Q&A (sonnet, read-only tools, $0.50).
- [x] **FR-4 (Entry Point Integration)**: Integrated in `colonyos run`, REPL, and Slack watcher. Correctly skipped for `--from-prd`, `--issue`, and resume flows.
- [x] **FR-5 (Fallback Behavior)**: Low confidence → falls through to full pipeline. Audit logging to `.colonyos/runs/triage_<timestamp>.json`.
- [x] **FR-6 (CLI Bypass)**: `--no-triage` flag added to `run` command.
- [x] **FR-7 (Configuration)**: `RouterConfig` dataclass with all specified fields, parsed from `config.yaml`.
- [x] **FR-8 (Audit Logging)**: `log_router_decision()` logs prompt, category, confidence, reasoning, source, timestamp.
- [x] **Phase.QA enum**: Added to models.py.
- [x] **qa.md template**: Well-structured instruction file.

### Quality

- [x] **236 tests pass** (0 failures).
- [x] **No TODOs/FIXMEs** in new code.
- [x] **Follows existing patterns**: Lazy imports of `run_phase_sync`, `dataclass(frozen=True)`, `sanitize_untrusted_content` reuse, Click option conventions.
- [x] **Config serialization**: Only writes non-default router values (delta serialization pattern matches existing config behavior).
- [x] **Input sanitization**: All user input passes through `sanitize_untrusted_content()` before LLM or log.

### Safety

- [x] **Least privilege**: Router has zero tools; Q&A has read-only tools only (`Read`, `Glob`, `Grep`).
- [x] **No secrets in code**.
- [x] **Error handling**: JSON parse failures → fail-open to CODE_CHANGE. LLM call failures → fail-open. Q&A failures → graceful error message. OSError on log writes → silent degradation with warning. `KeyboardInterrupt` handled in both REPL and run paths.

### Findings from Systems Engineering Perspective

**[src/colonyos/router.py:247-249]**: The artifact extraction pattern (`next(iter(result.artifacts.values()), "")`) is fragile. If `run_phase_sync` changes its artifact key convention, this silently returns empty and triggers the fail-open path. The comment acknowledges this but doesn't add a defensive assertion. This is acceptable for now — the fail-open behavior means it degrades gracefully — but worth watching.

**[src/colonyos/router.py:407-408]**: Timestamp in log filename uses `%f` (microseconds), which provides good uniqueness but creates many small files. No rotation or cleanup mechanism exists. Over months, `.colonyos/runs/` could accumulate thousands of triage log files. Not a launch blocker — these are tiny JSON files — but a cleanup story should be filed.

**[src/colonyos/slack.py:844-855]**: The Q&A agent runs synchronously inside `triage_message()`. For Slack, this means the event handler blocks for 5-10 seconds while the Q&A agent runs. Given Slack's 3-second acknowledgement timeout, the caller must already be handling this asynchronously (likely in a thread). Verified: the Slack watcher runs in a thread pool, so this is fine.

**[src/colonyos/slack.py:836]**: Low-confidence router results map to `actionable=False`, which means low-confidence non-code-change queries will be silently dropped by Slack rather than running the full pipeline. However, the CLI path correctly falls through to the pipeline for low-confidence results. This asymmetry is inherited from the existing Slack triage behavior (which already treats `actionable=False` as "skip"), so it's consistent.

**[src/colonyos/cli.py:497]**: In the REPL, the routing check uses `config.router.enabled` but doesn't check `--no-triage`. This is correct since the REPL doesn't have CLI flags, but there's no way to bypass routing in a REPL session. A `/no-triage` REPL command or config toggle would be a nice follow-up.

**[src/colonyos/config.py]**: `qa_model` field is a good addition beyond the PRD spec (which only mentioned `model` for classification). Using `sonnet` as default for Q&A vs `haiku` for classification is a smart split — questions benefit from reasoning quality.

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VERDICT: approve

FINDINGS:
- [src/colonyos/router.py:247-249]: Artifact extraction is fragile (`next(iter(values()))`) — degrades gracefully via fail-open, but worth hardening later if artifact schema changes
- [src/colonyos/router.py:407-408]: No rotation/cleanup for triage log files in `.colonyos/runs/` — will accumulate over time, file a follow-up story
- [src/colonyos/slack.py:836]: Low-confidence results map to `actionable=False` in Slack (silently dropped) vs fall-through in CLI (runs pipeline) — asymmetry is inherited from existing behavior and acceptable
- [src/colonyos/cli.py:497]: No way to bypass routing in REPL mode — minor UX gap, consider `/no-triage` command as follow-up

SYNTHESIS:
This is a clean, well-structured implementation that hits every PRD requirement without over-engineering. The two-stage design (zero-tool classifier → scoped executor) is the right architecture — it minimizes blast radius while keeping latency low. The fail-open behavior is correctly applied: JSON parse failures, unknown categories, and low-confidence results all default to the full pipeline, which is the safe choice at 3am. Error handling is thorough across all entry points (CLI, REPL, Slack) with graceful degradation rather than crashes. The code reuses existing infrastructure (`run_phase_sync`, `sanitize_untrusted_content`, `TriageResult`) instead of building parallel systems. The 236 passing tests cover parsing, configuration, error paths, and integration points well. The only items worth tracking are log file accumulation (operational hygiene) and the artifact extraction fragility (defensive hardening) — neither is a launch blocker. Ship it.