# Review by Staff Security Engineer (Round 1)

I have all the information I need. Here is my review:

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## Staff Security Engineer Review

### Checklist Assessment

#### Completeness
- [x] All functional requirements from the PRD are implemented (FR-1 through FR-22)
- [x] All tasks in the task file are marked complete (1.0–8.0)
- [x] No placeholder or TODO code remains

#### Quality
- [x] All Python tests pass (49 passed across `test_server.py` and `test_server_write.py`)
- [x] All frontend tests pass (48 tests across 8 test files)
- [x] Code follows existing project conventions (dataclass patterns, `sanitize_untrusted_content`, `validate_run_id_input`)
- [x] Dependencies are appropriately scoped (fastapi/uvicorn remain optional `[ui]` extras, added to `dev` for CI)
- [x] No unrelated changes included

#### Safety
- [x] No secrets or credentials in committed code
- [x] No destructive database operations
- [x] Error handling present for failure cases

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### Security-Specific Findings

**Authentication & Authorization (Strong):**
- Bearer token generated with `secrets.token_urlsafe(32)` — cryptographically secure
- Timing-safe comparison via `secrets.compare_digest()` — prevents timing oracle attacks
- Write endpoints gated behind explicit `COLONYOS_WRITE_ENABLED` env var — default is read-only
- `docs_url=None, redoc_url=None` — disables auto-generated API docs that could leak endpoint info

**Path Traversal Protection (Strong):**
- `GET /api/artifacts/{path}` uses a whitelist (`_ALLOWED_ARTIFACT_DIRS`) + `Path.resolve().is_relative_to()` defense-in-depth
- SPA catch-all `serve_spa()` also validates `file_path.resolve().is_relative_to(_resolved_dist_dir)` — prior review finding addressed
- `run_id` validation via existing `validate_run_id_input()` prevents directory traversal through run endpoints
- Test coverage includes path traversal attempts (`..%2F..%2Fetc%2Fpasswd`)

**Sensitive Data Redaction (Adequate with caveat):**
- `_SENSITIVE_CONFIG_FIELDS = {"slack", "ceo_persona"}` blocks both read exposure and write mutations — good
- **Concern**: This is a blocklist pattern. New sensitive fields added to `ColonyConfig` will be exposed by default. An allowlist would be safer but this was explicitly accepted in the prior decision gate as acceptable for V1 localhost-only.

**Network Binding (Strong):**
- Server binds to `127.0.0.1` only — not `0.0.0.0`
- CORS restricted to Vite dev server ports and only when `COLONYOS_DEV` env var is set

**Input Sanitization (Adequate):**
- `sanitize_untrusted_content()` applied to prompts, errors, project fields, persona fields, model strings on write paths
- `GET /api/runs/{run_id}` returns raw `asdict(show_result)` without sanitization — inconsistent with `/api/runs` list endpoint which sanitizes. Mitigated by React's JSX escaping, but a defense-in-depth gap.

**Rate Limiting (Present):**
- Max 1 concurrent run with lock-based guard — prevents runaway cost via API abuse

**Auth Token Storage (Minor concern):**
- Frontend stores token in `localStorage` — acceptable for localhost-only tool but worth noting this is not httpOnly cookie-level security. Given the threat model (single user, localhost), this is fine.

**Background Run Execution (Acceptable):**
- Runs launched in daemon threads. If the server process dies, the run is lost. The `active_run_count` decrement in `finally` block is correct.

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VERDICT: approve

FINDINGS:
- [src/colonyos/server.py:60-65]: `_config_to_dict()` uses blocklist pattern — new sensitive `ColonyConfig` fields will be exposed by default. Consider switching to allowlist or adding a maintenance comment. (MEDIUM, accepted in prior decision gate)
- [src/colonyos/server.py:131-157]: `GET /api/runs/{run_id}` returns unsanitized `asdict(show_result)` while `GET /api/runs` sanitizes each log entry — inconsistent defense-in-depth. (LOW, mitigated by React JSX escaping)
- [web/src/api.ts:24-26]: Auth token stored in `localStorage` — not httpOnly cookie-secured. Acceptable for localhost-only tool. (LOW)
- [src/colonyos/server.py:323-337]: Background run thread is a daemon thread — if the server is killed, the orchestrator run is silently terminated without cleanup. (LOW)
- [.gitignore:13]: `web/package-lock.json` is gitignored — contributors running `npm install` may get non-deterministic dependency versions. Mitigated by pre-built committed assets. (LOW)

SYNTHESIS:
From a security perspective, this implementation is well-engineered for a localhost-only developer tool. The critical security controls are all in place: cryptographically secure bearer tokens with timing-safe comparison, explicit opt-in for write mode via environment variable, defense-in-depth path traversal prevention (whitelist + resolve + relative-to check), sensitive field redaction, content sanitization, localhost-only binding, disabled API documentation, CORS locked to dev-only, and rate-limited run launching. The only structural concern is the blocklist pattern for sensitive field redaction, which was explicitly accepted in the prior review cycle. The sanitization inconsistency between list and detail run endpoints is a minor defense-in-depth gap. Overall, the security posture is appropriate for the threat model and I approve merging with the recommendation to track the blocklist concern for V2.