docs: add agent working rules and Copilot app configuration

[trsdn]

Part 1 of 3 of the Repository Quality Standard 1.18.1 rollout (safety net).

• AGENTS.md: new section "Working in this repository" (layout, one validation command, forbidden operations, credentials, attribution). The existing usage guide for agents that call the server is untouched below it. Addresses G02, G03, G05, G06, G07, B05, B14.
• .github/github-app.yml: points the Copilot app at AGENTS.md (G08).

Verified locally from a clean venv: ruff format --check ., ruff check ., mypy markitdown_mcp/ and pytest tests/unit/ (109 passed) all succeed.

🤖 Generated with Claude Code

https://claude.ai/code/session_01CdiwBVuH6DCEtFPPwxbXKc

[github-actions]

🔍 CI Quality Gates Summary

Overall Status: ✅ All Passed

Check	Status	Details	Action Required
🎨 Format	✅ Passed	ruff format check	None
🔧 Lint	✅ Passed	ruff linting	None
📝 Types	✅ Passed	mypy type checking	None
🧪 Tests	✅ Passed	Unit tests	None
📊 Coverage	81.8%	Minimum: 80%	None
🔌 MCP	✅ Valid	Protocol compliance	None
🔒 Security	✅ Clean	Dependency audit	None

🔗 Quick Links

• View detailed analysis
• See workflow logs

🛠️ Quick Fix Commands

# Fix most issues automatically
ruff format .
ruff check . --fix

# Run tests locally
pytest tests/unit/ --cov=markitdown_mcp

# Check types
mypy markitdown_mcp

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Last updated: 2026-09-21 19:43:47 UTC

[github-actions]

🔍 PR Quality Summary

CI Status

✅ Docs: success
✅ Security: success
✅ Quality: success

Metrics

Metric	Value	Trend
📊 Coverage	N/A	-
🧪 Tests	Test results pending	-
⏱️ Performance	No performance data	-

Quality Checks

• Format & Lint: Ruff formatting and linting
• Type Safety: MyPy strict type checking
• Security: Bandit, Safety, GitLeaks scanning
• MCP Protocol: Tool schema validation
• Documentation: Docstring coverage (80%+)

MCP Tools

• convert_file - Convert individual files to Markdown
• convert_directory - Batch convert directories
• list_supported_formats - Query supported file types

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_{🤖 Auto-generated by CI • Last updated: 2026-09-21 19:44 UTC}