diff --git a/code/app.py b/code/app.py
index ae9fe65..f3e0af9 100644
--- a/code/app.py
+++ b/code/app.py
@@ -27,7 +27,7 @@ async def test(request: Request):
 @app.post('/event')
 def handle_event(request: GiteaRequest):
     """ Handle event from webhook. """
-    # stop early if allowed
+    # stop early if asked
     commit_msg = request.head_commit['message']
     if commit_msg.lower().startswith('[skip ci]'):
         raise HTTPException(
@@ -39,6 +39,15 @@ def handle_event(request: GiteaRequest):
     logging.info('cloning repository: {repo_url}')
     local_repo_dir = clone_repository(repo_url)
     logging.info(f'local_repo_dir: {local_repo_dir}')
+    # locate runner script
+    runner_script_path = local_repo_dir / 'runner_script.yml'
+    if not runner_script_path.exists():
+        raise HTTPException(
+            status_code=200,
+            detail='no "runner_script.yml" in repository root'
+        )
+    
+    # send response
     raise HTTPException(
         status_code=202,
         detail='received task'