fix(webui): broadcast runtime model updates

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

tests/agent/test_self_model_preset.py

@@ -64,6 +64,30 @@ 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()
+    loop = AgentLoop(
+        bus=bus,
+        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")},
+    )
+
+    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",
+    }
+
+
 def test_model_preset_setter_replaces_provider_from_snapshot(tmp_path) -> None:
     old_provider = _provider("base-model", max_tokens=123)
     new_provider = _provider("anthropic/claude-opus-4-5", max_tokens=2048)

tests/channels/test_websocket_channel.py

@@ -230,7 +230,7 @@ async def test_send_delivers_json_message_with_media_and_reply() -> None:
 
 
 @pytest.mark.asyncio
-async def test_send_includes_webui_model_name_metadata() -> None:
+async def test_send_broadcasts_runtime_model_updates() -> None:
     bus = MagicMock()
     channel = WebSocketChannel({"enabled": True, "allowFrom": ["*"]}, bus)
     mock_ws = AsyncMock()
@@ -239,14 +239,20 @@ async def test_send_includes_webui_model_name_metadata() -> None:
     await channel.send(
         OutboundMessage(
             channel="websocket",
-            chat_id="chat-1",
-            content="switched",
-            metadata={"_webui_model_name": "openai/gpt-4.1"},
+            chat_id="*",
+            content="",
+            metadata={
+                "_runtime_model_updated": True,
+                "model": "openai/gpt-4.1",
+                "model_preset": "fast",
+            },
         )
     )
 
     payload = json.loads(mock_ws.send.call_args[0][0])
+    assert payload["event"] == "runtime_model_updated"
     assert payload["model_name"] == "openai/gpt-4.1"
+    assert payload["model_preset"] == "fast"
 
 
 @pytest.mark.asyncio

tests/command/test_model_command.py

@@ -64,8 +64,7 @@ async def test_model_command_lists_current_and_available_presets(tmp_path) -> No
     assert "Active preset: `(none)`" in out.content
     assert "`default`" in out.content
     assert "`fast`" in out.content
-    assert out.metadata["render_as"] == "text"
-    assert out.metadata["_webui_model_name"] == "base-model"
+    assert out.metadata == {"render_as": "text"}
 
 
 @pytest.mark.asyncio
@@ -76,7 +75,6 @@ async def test_model_command_switches_preset(tmp_path) -> None:
 
     assert "Switched model preset to `fast`." in out.content
     assert "Model: `openai/gpt-4.1`" in out.content
-    assert out.metadata["_webui_model_name"] == "openai/gpt-4.1"
     assert loop.model_preset == "fast"
     assert loop.model == "openai/gpt-4.1"
     assert loop.subagents.model == "openai/gpt-4.1"
@@ -92,7 +90,6 @@ async def test_model_command_switches_back_to_default(tmp_path) -> None:
     out = await cmd_model(_ctx(loop, "/model default", args="default"))
 
     assert "Switched model preset to `default`." in out.content
-    assert out.metadata["_webui_model_name"] == "base-model"
     assert loop.model_preset == "default"
     assert loop.model == "base-model"
     assert loop.context_window_tokens == 1000