Deterministic lossless compression (chunking, deduplication, Zstandard). See pyproject.toml for install and CLI entry mc. For lint/tests locally: pip install -e ".[dev]" then ruff check metacompressor scripts benchmarks, black --check metacompressor scripts benchmarks, and pytest metacompressor/tests. Git hooks: pre-commit install && pre-commit install --hook-type pre-push then pre-commit run --all-files (and pre-push runs full pytest via scripts/run_precommit_pytest.py).
Working contract (stay current): docs/METACOMPRESSOR_WORKING_CONTRACT.md. Governance: AGENTS.md. Layout: docs/repository-layout-policy.md. ADRs: docs/adr/. CI: .github/workflows/ci.yml.