fix(delegate): honor runtime default model during provider resolution

tests/tools/test_delegate.py

@@ -786,6 +786,26 @@ class TestDelegationCredentialResolution(unittest.TestCase):
         self.assertEqual(creds["api_mode"], "chat_completions")
         mock_resolve.assert_called_once_with(requested="openrouter")
 
+    @patch("hermes_cli.runtime_provider.resolve_runtime_provider")
+    def test_provider_resolution_uses_runtime_model_when_config_model_missing(self, mock_resolve):
+        """Named providers should propagate their runtime default model to children."""
+        mock_resolve.return_value = {
+            "provider": "custom",
+            "base_url": "https://my-server.example/v1",
+            "api_key": "sk-test-key",
+            "api_mode": "chat_completions",
+            "model": "server-default-model",
+        }
+        parent = _make_mock_parent(depth=0)
+        cfg = {"provider": "custom:my-server", "model": ""}
+
+        creds = _resolve_delegation_credentials(cfg, parent)
+
+        self.assertEqual(creds["model"], "server-default-model")
+        self.assertEqual(creds["provider"], "custom")
+        self.assertEqual(creds["base_url"], "https://my-server.example/v1")
+        mock_resolve.assert_called_once_with(requested="custom:my-server")
+
     def test_direct_endpoint_uses_configured_base_url_and_api_key(self):
         parent = _make_mock_parent(depth=0)
         cfg = {

tools/delegate_tool.py

@@ -2309,7 +2309,7 @@ def _resolve_delegation_credentials(cfg: dict, parent_agent) -> dict:
         )
 
     return {
-        "model": configured_model,
+        "model": configured_model or runtime.get("model") or None,
         "provider": runtime.get("provider"),
         "base_url": runtime.get("base_url"),
         "api_key": api_key,