How to contribute

This section covers the conventions a contributor needs to know before opening a PR. All of it is enforced either by CI workflows in .github/workflows/ or by per-package lint rules.

The guidance below summarizes what's in CLAUDE.md / AGENTS.md at the repo root and adds pointers into the source.

• Development workflow — branch, code, test, PR, merge cycle
• Testing — unit vs integration, fixtures, snapshots, VCR
• Patterns and conventions — public API stability, type hints, docstrings
• Tooling — uv, make, ruff, mypy, model-profile CLI, pre-commit

TL;DR for first-time contributors

1. Find an issue tagged good first issue or open one to discuss your change.
2. Fork, clone, branch.
3. cd libs/<package> for the package you're touching.
4. uv sync --all-groups to install everything in editable mode.
5. Make changes. Add tests in tests/unit_tests/ (and tests/integration_tests/ if relevant).
6. make format && make lint && make test from the package directory.
7. Open a PR with a Conventional Commits-style title (feat(scope):, fix(scope):, …).
8. CI will run only the affected packages (driven by .github/workflows/check_diffs.yml).

Code of conduct

The project follows a published Code of Conduct (linked from the GitHub repo's coc-ov-file tab). All contributions and review interactions are expected to be respectful and on-topic.

Where to ask questions

• Forum — https://forum.langchain.com
• Discord/Slack — links from the LangChain website
• GitHub Discussions — for design proposals or RFCs

For most code questions, opening a draft PR with a description of the problem is faster than waiting for a reviewer to chime in on a discussion thread.