Adds subagent_gate.py following the author_proofs/review_proofs pure-policy
pattern:
- assess_subagent_delegation: deterministic write tasks (issue claim,
branch creation, code edits, commits, PR creation, review, merge,
cleanup) are blocked for subagents unless explicitly allowed with a
recorded justification and the full inherited gate context (issue lock,
branch/worktree path, identity/profile, allowed tool class, command
deny list, validation ledger requirement, final report schema);
read-only delegation stays allowed; unknown task types fail closed.
- validate_subagent_report: subagent output is accepted only when it
carries the same proof fields as a parent workflow final report.
- Operator guide: new subagent_delegation rule in _GUIDE_RULES so MCP
clients discover the policy.
- tests/test_subagent_gate.py: 13 tests covering blocked write
delegation, justification requirement, missing/blank inherited
context, allowed read-only delegation, unknown tasks, and invalid
subagent final reports.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
