diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..6f83b3a
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,38 @@
+# Contributing
+
+## Branches
+
+| Branch | Purpose |
+|---|---|
+| `main` | Releases only – one merge commit per release, tagged `vX.Y.Z` |
+| `dev` | Integration branch for the next release |
+| `feature/<name>`, `fix/<name>` | Work branches, created from `dev` |
+
+1. Create a branch from `dev`: `git switch dev && git pull && git switch -c feature/<name>`.
+2. Open a pull request into `dev`. CI (ruff, pytest) must be green.
+3. Merge it with **Squash and merge** – one commit per feature or fix on `dev`.
+4. Do not commit directly to `main` or `dev`.
+
+## Release
+
+1. Update `CHANGELOG.md` (move `[Unreleased]` to `[X.Y.Z] - YYYY-MM-DD`) and `__version__` in
+   `src/aclib_import_mcp/__init__.py` on `dev` (via a `release/X.Y.Z` branch and pull request).
+2. Pull request `dev` -> `main`, merged with **Create a merge commit** (title `Release X.Y.Z`).
+   No squash, so `main` and `dev` keep a shared history and no merge back is needed.
+3. Tag the merge commit on `main` and push only this tag:
+   ```
+   git switch main && git pull
+   git tag -a vX.Y.Z -m "Release X.Y.Z"
+   git push origin vX.Y.Z
+   ```
+
+`git log --first-parent main` lists the releases only.
+
+## Development
+
+See [README – Development](README.md#development) for setup, tests and linting.
+
+- Code, comments and commit messages in English; commit subject in imperative mood, max. ~72 characters.
+- Text files use CRLF line endings and UTF-8 without BOM.
+- Tests that need Microsoft Access are marked `integration`; use copies of databases in `testdata\`
+  (git-ignored, trusted location), never your real databases.
diff --git a/README.md b/README.md
index a095eb0..a593907 100644
--- a/README.md
+++ b/README.md
@@ -121,6 +121,8 @@ uv run ruff format --check .
 Tests marked `integration` need Microsoft Access. Test databases go into `testdata\` (git-ignored, must be
 a trusted location).
 
+Branches, pull requests and releases: see [CONTRIBUTING.md](CONTRIBUTING.md).
+
 ## License
 
 [MIT](LICENSE)