feat(agent-runner): enforce 4.x host-owned execution

tests/unit_tests/pipeline/test_chat_handler.py

@@ -30,23 +30,9 @@ def mock_circular_import_chain():
         make_pipeline_handler_import_mocks,
         get_handler_modules_to_clear,
     )
-    from langbot_plugin.api.entities.builtin.provider.message import Message
 
     mocks = make_pipeline_handler_import_mocks()
 
-    # Create a default runner that yields a simple response
-    class DefaultRunner:
-        name = 'local-agent'
-
-        def __init__(self, app, config):
-            self.app = app
-            self.config = config
-
-        async def run(self, query):
-            yield Message(role='assistant', content='fake response')
-
-    mocks['langbot.pkg.provider.runner'].preregistered_runners = [DefaultRunner]
-
     clear = get_handler_modules_to_clear('chat')
 
     with isolated_sys_modules(mocks=mocks, clear=clear):
@@ -56,22 +42,27 @@ def mock_circular_import_chain():
 @pytest.fixture
 def fake_app():
     """Create FakeApp instance."""
-    import sys
+    from langbot_plugin.api.entities.builtin.provider.message import Message
 
     app = FakeApp()
 
     class FakeAgentRunOrchestrator:
+        runner_class = None
+
         async def try_claim_steering_from_query(self, query):
             return False
 
         async def run_from_query(self, query):
-            runner_cls = sys.modules['langbot.pkg.provider.runner'].preregistered_runners[0]
-            runner = runner_cls(app, {})
+            if self.runner_class is None:
+                yield Message(role='assistant', content='fake response')
+                return
+
+            runner = self.runner_class(app, {})
             async for result in runner.run(query):
                 yield result
 
         def resolve_runner_id_for_telemetry(self, query):
-            return 'local-agent'
+            return 'plugin:langbot-team/LocalAgent/default'
 
     app.agent_run_orchestrator = FakeAgentRunOrchestrator()
     return app
@@ -89,13 +80,11 @@ def mock_event_ctx():
 
 
 @pytest.fixture
-def set_runner():
-    """Factory fixture to set a custom runner for tests."""
+def set_runner(fake_app):
+    """Configure the orchestrator test double for one test."""
 
     def _set_runner(runner_class):
-        import sys
-
-        sys.modules['langbot.pkg.provider.runner'].preregistered_runners = [runner_class]
+        fake_app.agent_run_orchestrator.runner_class = runner_class
 
     return _set_runner