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+# Contributing to Mod³
+
+Thanks for your interest in Mod³. This document covers local development, testing, and PR workflow.
+
+## Development setup
+
+```sh
+git clone https://github.com/cogos-dev/mod3.git
+cd mod3
+python3.12 -m venv .venv && source .venv/bin/activate
+pip install -r requirements.txt
+pip install ruff pyright pytest
+```
+
+Requirements: Python 3.12+, macOS (Apple Silicon recommended for the TTS engines).
+
+## Running tests
+
+```sh
+ruff check .
+ruff format --check .
+pyright --pythonversion 3.12 engine.py vad.py http_api.py server.py
+pytest tests/ -v
+```
+
+CI runs all of the above on every PR (`.github/workflows/ci.yml`). Match the versions used there.
+
+## Project layout
+
+- `engine.py` — TTS engine dispatch (kokoro, piper, espeak-ng, system)
+- `vad.py` — voice-activity detection + hallucination filtering
+- `http_api.py` — FastAPI app exposing `/v1/jobs`, `/v1/voices`, `/v1/filter`
+- `server.py` — MCP server entry point
+- `tests/` — pytest suite
+- `integrations/openclaw/` — OpenClaw plugin manifest and extension
+
+## Submitting changes
+
+1. Fork the repo and create a branch from `main`
+2. Make your changes
+3. Run the full test suite above
+4. Update `CHANGELOG.md` under the Unreleased section
+5. Open a pull request using the org PR template
+
+Commit messages: conventional-commit style (`feat:`, `fix:`, `chore:`, etc.) is preferred but not enforced.
+
+## Reporting issues
+
+Use the org-level [Bug Report](https://github.com/cogos-dev/mod3/issues/new?template=bug.yml) or [Feature Request](https://github.com/cogos-dev/mod3/issues/new?template=feature.yml) forms.
+
+## License
+
+By contributing, you agree that your contributions will be licensed under the [MIT License](LICENSE).