diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 0000000..deb2681
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,5 @@
+[run]
+branch = True
+source =
+    ffmpegfyMe
+relative_files = True
diff --git a/.github/workflows/python-tests.yml b/.github/workflows/python-tests.yml
index 69215a7..057ab14 100644
--- a/.github/workflows/python-tests.yml
+++ b/.github/workflows/python-tests.yml
@@ -16,7 +16,10 @@ jobs:
       - uses: actions/setup-python@6d4fd22b20465ccc0f7354476588e8df7c9ca0e0 # v7.1.0
         with:
           python-version: "3.11"
-      - run: python -m unittest discover -v
+      - run: python -m pip install -r requirements-dev.txt
+      - run: python -m coverage run -m unittest discover -v
+      - name: Add branch coverage summary
+        run: python -m coverage report --show-missing --format=markdown >> "$GITHUB_STEP_SUMMARY"
 
   container_smoke:
     name: Container smoke
diff --git a/.gitignore b/.gitignore
index e3a1731..1314a9f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,6 +14,8 @@ __pycache__/
 *.pyc
 *.pyo
 .env
+.coverage
+.venv/
 
 # Editor/OS metadata
 .DS_Store
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 79de319..b352063 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -27,7 +27,19 @@ Common types: `feat`, `fix`, `docs`, `style`, `refactor`, `test`, `chore`,
 
 ## Tests and CI
 
-- Run the Python test suite locally with `python3 -m unittest discover -v`.
+Use an isolated virtual environment to run tests with branch coverage:
+
+```sh
+python3 -m venv .venv
+.venv/bin/python -m pip install -r requirements-dev.txt
+.venv/bin/python -m coverage run -m unittest discover -v
+.venv/bin/python -m coverage report --show-missing
+```
+
+The reported `ffmpegfyMe.py` percentage combines deterministic policy and
+integration code. It is a module-level baseline, not core-policy-only
+coverage. Issue #32 defines the target scope.
+
 - The Python test suite runs on PRs and pushes to main.
 - Watch the required CI checks on the pull request and run the current CI
   checks before requesting review.
diff --git a/README.md b/README.md
index a553de1..54a6b3d 100644
--- a/README.md
+++ b/README.md
@@ -152,11 +152,7 @@ task ffmpegfy:run
 
 ## Tests
 
-Run the Python test suite:
-
-```bash
-python3 -m unittest discover -v
-```
+Run the Python test suite with branch coverage. See [CONTRIBUTING.md](CONTRIBUTING.md#tests-and-ci) for the local environment and commands.
 
 GitHub Actions runs it on pull requests to `main` and pushes to `main`.
 
diff --git a/requirements-dev.txt b/requirements-dev.txt
new file mode 100644
index 0000000..f76ca6c
--- /dev/null
+++ b/requirements-dev.txt
@@ -0,0 +1 @@
+coverage==7.17.0