refactor(agent): inject runtime model publisher

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/agent/test_self_model_preset.py

@@ -64,28 +64,21 @@ def test_model_preset_setter_updates_state(tmp_path) -> None:
     assert loop.dream.model == "openai/gpt-4.1"
 
 
-def test_model_preset_setter_publishes_runtime_model_event(tmp_path) -> None:
-    bus = MessageBus()
+def test_model_preset_setter_calls_runtime_model_publisher(tmp_path) -> None:
+    published: list[tuple[str, str | None]] = []
     loop = AgentLoop(
-        bus=bus,
+        bus=MessageBus(),
         provider=_provider("base-model", max_tokens=123),
         workspace=tmp_path,
         model="base-model",
         context_window_tokens=1000,
         model_presets={"fast": ModelPresetConfig(model="openai/gpt-4.1")},
+        runtime_model_publisher=lambda model, preset: published.append((model, preset)),
     )
 
     loop.set_model_preset("fast")
 
-    event = bus.outbound.get_nowait()
-    assert event.channel == "websocket"
-    assert event.chat_id == "*"
-    assert event.content == ""
-    assert event.metadata == {
-        "_runtime_model_updated": True,
-        "model": "openai/gpt-4.1",
-        "model_preset": "fast",
-    }
+    assert published == [("openai/gpt-4.1", "fast")]
 
 
 def test_model_preset_setter_replaces_provider_from_snapshot(tmp_path) -> None:

tests/channels/test_websocket_channel.py

@@ -14,6 +14,7 @@ from websockets.exceptions import ConnectionClosed
 from websockets.frames import Close
 
 from nanobot.bus.events import OutboundMessage
+from nanobot.bus.queue import MessageBus
 from nanobot.channels.websocket import (
     WebSocketChannel,
     WebSocketConfig,
@@ -25,6 +26,7 @@ from nanobot.channels.websocket import (
     _parse_inbound_payload,
     _parse_query,
     _parse_request_path,
+    publish_runtime_model_update,
 )
 from nanobot.config.loader import load_config, save_config
 from nanobot.config.schema import Config
@@ -231,23 +233,13 @@ async def test_send_delivers_json_message_with_media_and_reply() -> None:
 
 @pytest.mark.asyncio
 async def test_send_broadcasts_runtime_model_updates() -> None:
-    bus = MagicMock()
+    bus = MessageBus()
     channel = WebSocketChannel({"enabled": True, "allowFrom": ["*"]}, bus)
     mock_ws = AsyncMock()
     channel._attach(mock_ws, "chat-1")
 
-    await channel.send(
-        OutboundMessage(
-            channel="websocket",
-            chat_id="*",
-            content="",
-            metadata={
-                "_runtime_model_updated": True,
-                "model": "openai/gpt-4.1",
-                "model_preset": "fast",
-            },
-        )
-    )
+    publish_runtime_model_update(bus, "openai/gpt-4.1", "fast")
+    await channel.send(bus.outbound.get_nowait())
 
     payload = json.loads(mock_ws.send.call_args[0][0])
     assert payload["event"] == "runtime_model_updated"
@@ -255,6 +247,27 @@ async def test_send_broadcasts_runtime_model_updates() -> None:
     assert payload["model_preset"] == "fast"
 
 
+@pytest.mark.asyncio
+async def test_runtime_model_update_publisher_uses_websocket_outbound_event() -> None:
+    bus = MessageBus()
+
+    publish_runtime_model_update(
+        bus,
+        "openai/gpt-4.1",
+        "fast",
+    )
+
+    event = bus.outbound.get_nowait()
+    assert event.channel == "websocket"
+    assert event.chat_id == "*"
+    assert event.content == ""
+    assert event.metadata == {
+        "_runtime_model_updated": True,
+        "model": "openai/gpt-4.1",
+        "model_preset": "fast",
+    }
+
+
 @pytest.mark.asyncio
 async def test_send_stages_external_media_as_signed_url(monkeypatch, tmp_path) -> None:
     bus = MagicMock()