fix(pi): select configured startup models

tests/unit/test_agent_provider.py

@@ -284,6 +284,7 @@ class TestAgentProviderRuntime(unittest.TestCase):
             ("/home/node/.pi/agent/models.json",),
             tuple(f.guest_path for f in plan.files),
         )
+        self.assertEqual(("--models", "ollama/qwen2.5-coder:7b"), plan.startup_args)
         provider = models["providers"]["ollama"]
         self.assertEqual("http://ollama:11434/v1", provider["baseUrl"])
         self.assertEqual("openai-completions", provider["api"])
@@ -348,6 +349,10 @@ class TestAgentProviderRuntime(unittest.TestCase):
             [{"id": "google/gemma-4-26b-a4b-it:free"}],
             provider["models"],
         )
+        self.assertEqual(
+            ("--models", "openrouter/google/gemma-4-26b-a4b-it:free"),
+            plan.startup_args,
+        )
         self.assertEqual("openrouter.ai", plan.egress_routes[0].host)
         self.assertEqual("Bearer", plan.egress_routes[0].auth_scheme)
         self.assertEqual("OPENROUTER_API_KEY", plan.egress_routes[0].token_ref)

tests/unit/test_cli_start_settle.py

@@ -80,5 +80,28 @@ class TestSettleState(_FakeHomeMixin, unittest.TestCase):
         start_mod.settle_state("")  # should not raise
 
 
+class TestAttachAgent(unittest.TestCase):
+    def test_passes_provider_startup_args(self):
+        class Bottle:
+            argv: list[str] = []
+
+            def exec_agent(self, argv: list[str], *, tty: bool = True) -> int:
+                self.argv = list(argv)
+                return 0
+
+        bottle = Bottle()
+        exit_code = start_mod.attach_agent(
+            bottle,  # type: ignore[arg-type]
+            agent_provider_template="pi",
+            startup_args=("--models", "openrouter/google/gemma"),
+        )
+
+        self.assertEqual(0, exit_code)
+        self.assertEqual(
+            ["--models", "openrouter/google/gemma"],
+            bottle.argv,
+        )
+
+
 if __name__ == "__main__":
     unittest.main()