diff --git a/tools/scripts/lint.py b/tools/scripts/lint.py
index 9bd054f..9ebc335 100644
--- a/tools/scripts/lint.py
+++ b/tools/scripts/lint.py
@@ -19,12 +19,16 @@ FILES_TO_EXCLUDE = [
   'Shared/Levels.cs']
 
 
+num_errors = 0
+
+
 def emit_error(filename, line_num, error):
+  global num_errors
+  num_errors += 1
   print('%s:%d: %s' % (filename, line_num, error))
 
 
 def lint_csharp(filename):
-  errors = []
   with open(filename) as f:
     for i, line in enumerate(f):
       line_num = i + 1
@@ -57,11 +61,17 @@ def main(args):
   # Remove generated files (of which there's lots).
   for exclusion_pattern in FILES_TO_EXCLUDE:
     csharp_files = [x for x in csharp_files if exclusion_pattern not in x]
-  print('checking %d files' % len(csharp_files))
 
   for filename in csharp_files:
     lint_csharp(filename)
 
+  print('checked %d files and found %d errors' % (
+      len(csharp_files), num_errors))
+
+  if num_errors:
+    return 1
+  return 0
+
 
 if __name__ == '__main__':
-  main(sys.argv[1:])
+  sys.exit(main(sys.argv[1:]))