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

Based on my comprehensive review of the implementation against the PRD, here is my assessment:

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## Principal Systems Engineer Review: Intent Router Agent

### Implementation Status Summary

**What's Implemented (Tasks 1.0-5.0):**
- ✅ `RouterCategory` enum with CODE_CHANGE, QUESTION, STATUS, OUT_OF_SCOPE
- ✅ `RouterResult` dataclass (frozen, immutable)
- ✅ `_build_router_prompt()` with proper input sanitization
- ✅ `_parse_router_response()` with JSON/markdown-fence handling and fail-open fallback
- ✅ `route_query()` using haiku model, no tools, $0.05 budget
- ✅ `Phase.QA` enum added to models.py
- ✅ `RouterConfig` dataclass with proper validation (enabled, model, confidence_threshold, qa_budget)
- ✅ Q&A instruction template (`instructions/qa.md`) with read-only constraints
- ✅ `answer_question()` function with read-only tools (Read, Glob, Grep)
- ✅ Config parsing and serialization for router section
- ✅ 217 unit tests passing

**What's NOT Implemented (Tasks 6.0-10.0):**
- ❌ **FR-6: `--no-triage` CLI flag** - Not added to `run` command
- ❌ **FR-4: CLI integration** - `route_query()` never called from `cli.py`
- ❌ **FR-4: REPL integration** - No routing before orchestrator
- ❌ **FR-2: Slack refactor** - `triage_message()` in slack.py unchanged
- ❌ **FR-8: Audit logging** - No `_log_router_decision()`, no `.colonyos/runs/triage_<timestamp>.json`
- ❌ **README documentation** - No router config or `--no-triage` documentation

### Systems Engineering Concerns

**1. No Error Propagation Path**
The `route_query()` function properly fails-open on LLM errors (returns CODE_CHANGE with confidence=0.0), but since it's never wired into the CLI, there's no observable failure mode in production. When it IS wired in, we need to ensure:
- Routing failures don't break the main pipeline
- Timeouts don't block user interaction

**2. Missing Observability**
FR-8 (audit logging) is critical for debugging routing decisions at 3am. Without it:
- No way to understand why a question got routed to full pipeline
- No metrics for routing accuracy
- No data for tuning confidence thresholds

The PRD specified `.colonyos/runs/triage_<timestamp>.json` with prompt, category, confidence, reasoning, source - none of this exists.

**3. No Confidence Threshold Check in Code Path**
The config has `confidence_threshold: 0.7`, but since the router isn't wired to CLI, there's no code that actually checks `if result.confidence < threshold: run_full_pipeline()`. This fail-open behavior specified in FR-5 is defined but not exercised.

**4. Race Condition Risk (Future)**
When the router IS integrated, there's a potential race between:
- Router classifying intent
- User pressing Ctrl-C during classification
- Pipeline starting before classification completes

The two-phase design is sound, but the integration needs clear cancellation handling.

**5. Read-Only Tool Set is Correct**
The Q&A agent properly restricts to `["Read", "Glob", "Grep"]` - no Bash, Write, or Edit. This least-privilege approach is good security hygiene.

### What's Working Well

1. **Fail-Open Design**: Both `_parse_router_response()` and `route_query()` properly default to CODE_CHANGE when uncertain - this prevents questions from accidentally being swallowed.

2. **Input Sanitization**: Uses `sanitize_untrusted_content()` on all user input - prevents prompt injection at the classification layer.

3. **Frozen Dataclass**: `RouterResult` is immutable, preventing accidental mutation.

4. **Budget Controls**: $0.05 for routing, $0.50 for Q&A answers - well within PRD spec.

5. **Test Coverage**: 217 tests covering enum values, parsing edge cases, API contract validation.

### The Core Issue

The implementation is only ~50% complete. The foundational modules (`router.py`, config, models, tests) are solid, but **the router is never actually used**. The entire value proposition of the PRD - "Users asking questions should get answers in 5-10 seconds" - is unrealized because:

1. `colonyos run "what does this function do?"` still runs the full pipeline
2. No `--no-triage` flag exists
3. No routing decision is ever made

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VERDICT: request-changes

FINDINGS:
- [src/colonyos/cli.py]: Router not integrated - `route_query()` never called; PRD FR-4 (entry point integration) not implemented
- [src/colonyos/cli.py]: Missing `--no-triage` flag (PRD FR-6); only unrelated `force=force` line added
- [src/colonyos/router.py]: No `_log_router_decision()` function; FR-8 (audit logging) not implemented
- [src/colonyos/slack.py]: Triage logic not refactored; FR-2 (reuse Slack infrastructure) not implemented
- [README.md]: No documentation for router configuration or `--no-triage` flag (Task 10.1, 10.2)
- [cOS_tasks/]: All tasks 1.0-5.0 should be marked complete; tasks 6.0-10.0 remain unchecked

SYNTHESIS:
The implementation is architecturally sound but incomplete - approximately 50% of the PRD requirements are met. The router module, configuration, Q&A agent, and models are well-designed with proper fail-open behavior, input sanitization, and immutable data structures. Test coverage is excellent at 217 passing tests. However, the core user-facing functionality is missing: the router is never called from CLI or REPL, there's no `--no-triage` bypass flag, no audit logging, and no Slack integration. From a systems engineering perspective, the foundation is reliable, but the feature doesn't actually work end-to-end - running `colonyos run "what does this function do?"` still triggers the full pipeline. The remaining tasks (6.0-10.0) must be completed before this feature delivers value.
