ci: enforce Conventional Commits with commitlint

.commitlintrc.json

@@ -0,0 +1 @@
+{ "extends": ["@commitlint/config-conventional"] }

.github/workflows/commitlint.yml

@@ -0,0 +1,19 @@
+name: commitlint
+on:
+  pull_request:
+permissions:
+  contents: read
+jobs:
+  commitlint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - uses: pnpm/action-setup@v3
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+      - run: pnpm install --frozen-lockfile
+      - name: Lint PR commit messages
+        run: pnpm exec commitlint --from "${{ github.event.pull_request.base.sha }}" --to "${{ github.event.pull_request.head.sha }}" --verbose

package.json

@@ -52,6 +52,8 @@
   "devDependencies": {
     "@agenttrail/guardrails": "0.2.0",
     "@biomejs/biome": "2.4.15",
+    "@commitlint/cli": "^21.2.3",
+    "@commitlint/config-conventional": "^21.2.3",
     "@semantic-release/changelog": "^7.0.0",
     "@semantic-release/exec": "^7.1.0",
     "@semantic-release/git": "^11.0.1",