# Review by Staff Security Engineer (Round 1)

## Staff Security Engineer — Review Complete

**VERDICT: approve** ✅

### Key Findings

**Security positives:**
1. **Least privilege preserved** — `allowed_tools=["Read", "Glob", "Grep"]` enforcement at orchestrator.py:3510 is unchanged. The fix operates at the instruction layer only, not the enforcement layer.
2. **Defense in depth achieved** — Two layers now protect against unauthorized tool use: CLI-level enforcement (hard reject) + prompt-level instruction (prevents the agent from even trying).
3. **No privilege escalation** — No expanded tool access, no budget changes, no write permissions added. The learn agent remains strictly read-only.
4. **No secrets or injection vectors** — Template variables are operator-controlled config values, not user input.

**Minor advisories (non-blocking):**
- Negative constraint lists specific tools but relies on "or any other tool" catch-all for tools like `WebFetch`, `WebSearch` — practically sufficient.
- Test substring assertions match common English words but are collectively specific enough to avoid false positives.

**Bottom line:** This is a clean, minimal, correctly-scoped fix that addresses the root cause without weakening any security enforcement. The learn phase's tool restrictions are maintained at both the enforcement and instruction layers. No reservations.

VERDICT: approve

FINDINGS:
- [src/colonyos/instructions/learn.md]: Correctly adds tool constraints and negative constraints; no security issues
- [src/colonyos/instructions/learn.md]: Template variables ({reviews_dir}, {learnings_path}) are operator-controlled — no injection risk (pre-existing pattern)
- [tests/test_orchestrator.py]: Two new regression tests adequately cover prompt-tool alignment; substring matching is sufficient given combined assertions
- [src/colonyos/orchestrator.py]: allowed_tools enforcement at line 3510 is unchanged and correctly restricts to Read/Glob/Grep only

SYNTHESIS:
From a security perspective, this is an exemplary fix. The root cause was a prompt-program mismatch causing the agent to attempt unauthorized tool use, and the fix addresses this at the instruction layer without relaxing any enforcement. The learn phase remains strictly read-only with a hard-coded tool allowlist enforced at the CLI level. The negative constraint in learn.md provides defense-in-depth by preventing the agent from even attempting disallowed tools, reducing both crash risk and budget waste from tool-rejection retry loops. No secrets, no privilege escalation, no new attack surface. Approve without reservations.