diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 595769c..cf31a55 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -29,6 +29,20 @@ jobs:
       - name: Check out repository
         uses: actions/checkout@v6
 
+      - name: Require release tag
+        run: |
+          if [ "${GITHUB_REF_TYPE}" != "tag" ]; then
+            echo "Publish must be run from a release tag, not ${GITHUB_REF_TYPE}: ${GITHUB_REF_NAME}" >&2
+            exit 1
+          fi
+          case "${GITHUB_REF_NAME}" in
+            v*) ;;
+            *)
+              echo "Publish tag must start with 'v': ${GITHUB_REF_NAME}" >&2
+              exit 1
+              ;;
+          esac
+
       - name: Install uv
         uses: astral-sh/setup-uv@v8.1.0
         with:
@@ -42,6 +56,15 @@ jobs:
       - name: Install dependencies
         run: uv sync --locked --python 3.14
 
+      - name: Verify tag matches package version
+        run: |
+          PACKAGE_VERSION=$(uv run python -c "import tomllib; print(tomllib.load(open('pyproject.toml', 'rb'))['project']['version'])")
+          TAG_VERSION="${GITHUB_REF_NAME#v}"
+          if [ "${PACKAGE_VERSION}" != "${TAG_VERSION}" ]; then
+            echo "Package version ${PACKAGE_VERSION} does not match tag ${GITHUB_REF_NAME}" >&2
+            exit 1
+          fi
+
       - name: Run tests
         run: uv run pytest
 
diff --git a/RELEASE.md b/RELEASE.md
index cde849f..8c6229b 100644
--- a/RELEASE.md
+++ b/RELEASE.md
@@ -46,9 +46,9 @@ git push origin vX.Y.Z
 ```
 
 10. Create a GitHub Release from the tag using the changelog section as release notes.
-11. Run the manual `Publish` workflow for TestPyPI first.
+11. Run the manual `Publish` workflow from the release tag for TestPyPI first.
 12. Install from TestPyPI in a clean environment and smoke-test imports.
-13. Run the manual `Publish` workflow for PyPI only after TestPyPI passes.
+13. Run the manual `Publish` workflow from the release tag for PyPI only after TestPyPI passes.
 
 ## TestPyPI Smoke Test