diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..daaf4d4
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,27 @@
+name: ci
+
+# Minimal merge gate, provisioned by grahambrooks/auto-managed (ensure_ci.sh).
+# Dependency PRs cannot auto-merge without a green check, so every managed repo
+# needs at least this. Edit freely — the control plane never overwrites it.
+
+on:
+  pull_request:
+  push:
+    branches: [main, master]
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - uses: bazel-contrib/setup-bazel@0.15.0
+        with:
+          bazelisk-cache: true
+          disk-cache: ${{ github.workflow }}
+          repository-cache: true
+      - run: bazel build //...
+      - run: bazel test //... --test_output=errors