diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e9b2134b..131e4cd7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,6 +20,10 @@ jobs:
           cache: maven
       - name: Build with Maven
         run: mvn -B install
+      - name: Validate error catalog
+        run: |
+          python3 -m unittest discover -v
+          python3 tools/error_catalog.py validate errors/catalog.yml
       - name: SpotBugs Check
         run: mvn spotbugs:check
       - name: OWASP Dependency Check
diff --git a/.gitignore b/.gitignore
index f3e49049..7a92f7a4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,6 +32,7 @@ build/
 **/build/
 
 *.py
+!tools/__init__.py
 !tools/error_catalog.py
 !tools/test_error_catalog.py
 
diff --git a/tools/__init__.py b/tools/__init__.py
new file mode 100644
index 00000000..2b740709
--- /dev/null
+++ b/tools/__init__.py
@@ -0,0 +1 @@
+"""Repository maintenance tools and their tests."""