--- a/scripts/repository-candidate-gate
+++ b/scripts/repository-candidate-gate
@@ -388,7 +388,7 @@
 
 def main() -> int:
     parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
-    parser.add_argument("--config", required=True)
+    parser.add_argument("--config", help="repository gate policy (required for the main process)")
     parser.add_argument("--candidate", default=".", help="candidate tree (default: working directory)")
     parser.add_argument("--baseline", help="baseline tree (default: config baseline, the published tree)")
     parser.add_argument("--worker", nargs="+", help=argparse.SUPPRESS)
@@ -397,6 +397,9 @@
         kind, root, out, *atoms = args.worker
         worker_packages(root, out) if kind == "packages" else worker_resolve(root, atoms, out)
         return 0
+
+    if not args.config:
+        parser.error("--config is required for the main gate process")
 
     # Portage sources ebuilds as the portage user: the work tree must be traversable.
     os.umask(0o022)
--- /dev/null
+++ b/tests/test_candidate_gate.py
@@ -0,0 +1,21 @@
+from importlib.machinery import SourceFileLoader
+from importlib.util import module_from_spec, spec_from_loader
+from pathlib import Path
+from unittest.mock import patch
+import unittest
+
+
+class CandidateGateCommandTests(unittest.TestCase):
+    def test_worker_protocol_does_not_require_main_process_policy(self):
+        script = Path(__file__).resolve().parents[1] / 'scripts/repository-candidate-gate'
+        loader = SourceFileLoader('candidate_gate_test', str(script))
+        module = module_from_spec(spec_from_loader(loader.name, loader))
+        loader.exec_module(module)
+        with patch.object(module.sys, 'argv', [str(script), '--worker', 'packages', '/isolated/root', '/isolated/out']), \
+                patch.object(module, 'worker_packages') as worker:
+            self.assertEqual(module.main(), 0)
+            worker.assert_called_once_with('/isolated/root', '/isolated/out')
+
+
+if __name__ == '__main__':
+    unittest.main()