diff --git a/.ci-policy.md b/.ci-policy.md
new file mode 100644
index 0000000..deb4ef2
--- /dev/null
+++ b/.ci-policy.md
@@ -0,0 +1 @@
+CodeQL scans main weekly to batch this quiet repository's changes without adding daily scans; PR/manual scans remain enabled and CI/deployment gates are unchanged.
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
new file mode 100644
index 0000000..285d561
--- /dev/null
+++ b/.github/workflows/codeql.yml
@@ -0,0 +1,46 @@
+name: CodeQL
+
+on:
+  pull_request:
+  schedule:
+    - cron: "37 5 * * 1"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Keep scheduled scans running; only superseded PR scans should be cancelled.
+concurrency:
+  group: codeql-${{ github.event_name }}-${{ github.event_name == 'workflow_dispatch' && github.run_id || github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+jobs:
+  analyze:
+    name: Analyze (${{ matrix.language }})
+    runs-on: ubuntu-24.04
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+    strategy:
+      fail-fast: false
+      matrix:
+        language:
+          - actions
+          - javascript-typescript
+    steps:
+      - name: Check out source
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@9b3254085494b55a0f7c4c2b3d2d52cc712ce370 # v4.39.1
+        with:
+          languages: ${{ matrix.language }}
+          build-mode: none
+
+      - name: Analyze
+        uses: github/codeql-action/analyze@9b3254085494b55a0f7c4c2b3d2d52cc712ce370 # v4.39.1
+        with:
+          category: /language:${{ matrix.language }}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 18784d6..3c09983 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Batch main CodeQL analysis weekly while preserving PR and manual scans.
+
 - Accept identifier-free reporting-installation counts into an optional aggregate-only D1 `(day, gap, reports)` histogram with 90-day pruning; successful update answers advertise the server UTC day only when the binding exists, and production stays unbound. Thanks @roboclaw-bot.
 - Maintain public vocabulary with daily checks of immutable stable releases, retained backfill, isolated generation, constrained publication, serialized deployment, and retryable exact-commit rollout verification.
 - Preserve all reported public channel, provider, and plugin names instead of truncating each list to 32 before validation; keep upload and Analytics Engine byte limits covered by regression tests.