diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index ee1bf991..2a28f4b4 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -43,6 +43,13 @@ repos:
         pass_filenames: false
         verbose: true
         always_run: true
+      - id: block-codeql-db-commits
+        name: Prevent committing CodeQL DB artifacts
+        entry: bash scripts/pre-commit-hooks/block-codeql-db-commits.sh
+        language: system
+        pass_filenames: false
+        verbose: true
+        always_run: true
 
       # === MANUAL/CI-ONLY HOOKS ===
       # These are slow and should only run on-demand or in CI
diff --git a/scripts/pre-commit-hooks/block-codeql-db-commits.sh b/scripts/pre-commit-hooks/block-codeql-db-commits.sh
new file mode 100644
index 00000000..aae6bae4
--- /dev/null
+++ b/scripts/pre-commit-hooks/block-codeql-db-commits.sh
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+set -euo pipefail
+staged=$(git diff --cached --name-only | tr '\r' '\n' || true)
+if [ -n "${staged}" ]; then
+  # Exclude the pre-commit-hooks directory and this script itself
+  filtered=$(echo "$staged" | grep -v '^scripts/pre-commit-hooks/' | grep -v '^data/backups/' || true)
+  if echo "$filtered" | grep -q "codeql-db"; then
+    echo "Error: Attempting to commit CodeQL database artifacts (codeql-db)." >&2
+    echo "These should not be committed. Remove them or add to .gitignore and try again." >&2
+    echo "Tip: Use 'scripts/repo_health_check.sh' to validate repository health." >&2
+    exit 1
+  fi
+fi
+exit 0