Purpose
-------
Regression tests for Phase 5B write-tool Pydantic models
(:mod:`oct.mcp.validator`) and argv builders (:mod:`oct.mcp.executor`).
Responsibilities
----------------
- Verify all 11 write-tool models (defaults, unknown field rejection,
confirm field).
- Verify ``FormatArgs`` double guard and ``GitCommitArgs`` safety.
- Verify path traversal (T-02) and shell metacharacter rejection.
- Verify strict/airgapped profile blocks write tools.
- Verify argv builder spot-checks (format dry-run, format fix, git
commit).
- Verify T-06 privilege escalation and T-06b strict-profile denial.
Diagnostics
-----------
Domain: MCP-TESTS
Levels:
L2 — test lifecycle
L3 — assertion details
L4 — deep tracing
Contracts
---------
- Tests are in-memory validation and policy checks; no subprocess or
filesystem writes.