What does this PR do?

Post-tool-call path discovery scanned any directory for AGENTS.md, CLAUDE.md, and .cursorrules files, even those outside the intended workspace. A tool call touching a file elsewhere on disk could silently inject unrelated instruction files into the agent context, causing unexpected behavior drift and cross-project leakage.

Related Issue

Fixes #14471

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• agent/subdirectory_hints.py: Scoped discovery to active workspace boundary
• tests/agent/test_subdirectory_hints.py: 26 tests

How to Test

python -m pytest -o 'addopts=' tests/agent/test_subdirectory_hints.py -v

Result: 26 passed.

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: macOS 15 (Darwin 24.6.0), Python 3.14.2

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• I've updated tool descriptions/schemas if I changed tool behavior — or N/A

Screenshots / Logs

python -m pytest -o 'addopts=' tests/agent/test_subdirectory_hints.py -v
26 passed