assign_to_bus

Instructions

Implementation Reference

• fmod_mcp/tools/events.py:159-172 (handler)

  Core implementation of the assign_to_bus tool. Uses studio.project.lookup() to find the event and bus by path, then sets evt.masterTrack.mixerGroup.output = bus to route the event's master track output to the specified mixer bus.

  async def assign_to_bus(
      client: StudioClient,
      event_path: str,
      bus_path: str,
  ) -> dict[str, Any]:
      js = f"""
          var evt = studio.project.lookup({json.dumps(event_path)});
          if (!evt) throw new Error("Event not found: " + {json.dumps(event_path)});
          var bus = studio.project.lookup({json.dumps(bus_path)});
          if (!bus) throw new Error("Bus not found: " + {json.dumps(bus_path)});
          evt.masterTrack.mixerGroup.output = bus;
          return {{ path: evt.getPath(), bus: bus.getPath() }};
      """
      return await client.eval(js)

• fmod_mcp/server.py:126-129 (registration)

  Server-side registration of the assign_to_bus tool via the @mcp.tool() decorator. Wraps the core handler from events module, accepting event_path and bus_path strings, and returns a dict.

  @mcp.tool()
  async def assign_to_bus(event_path: str, bus_path: str) -> dict[str, Any]:
      """Route the event's master track output to a mixer bus."""
      return await events.assign_to_bus(_studio(), event_path, bus_path)

• fmod_mcp/tools/events.py:159-172 (schema)

  The function signature defines the schema: event_path (str) and bus_path (str) as inputs, returning a dict with 'path' and 'bus' keys.

  async def assign_to_bus(
      client: StudioClient,
      event_path: str,
      bus_path: str,
  ) -> dict[str, Any]:
      js = f"""
          var evt = studio.project.lookup({json.dumps(event_path)});
          if (!evt) throw new Error("Event not found: " + {json.dumps(event_path)});
          var bus = studio.project.lookup({json.dumps(bus_path)});
          if (!bus) throw new Error("Bus not found: " + {json.dumps(bus_path)});
          evt.masterTrack.mixerGroup.output = bus;
          return {{ path: evt.getPath(), bus: bus.getPath() }};
      """
      return await client.eval(js)

• tests/test_server_registration.py:19-42 (registration)

  Test registration: 'assign_to_bus' is listed in the EXPECTED_TOOLS set to verify it is properly registered on the server.

      "assign_to_bus",
      # effects
      "list_effect_types",
      "add_effect",
      "list_effects",
      "get_effect",
      "set_effect_param",
      "remove_effect",
      "bypass_effect",
      # project
      "save_project",
      "build_banks",
      # escape
      "run_js",
  }
  
  
  def test_all_tools_registered():
      tools = set(mcp._tool_manager._tools.keys())
      missing = EXPECTED_TOOLS - tools
      extra = tools - EXPECTED_TOOLS
      assert not missing, f"Missing tools: {missing}"
      assert not extra, f"Unexpected extra tools: {extra}"

• tests/test_tools.py:167-174 (helper)

  Test for the assign_to_bus tool, verifying that the JavaScript sent includes 'masterTrack.mixerGroup.output'.

  async def test_assign_to_bus(
      client: StudioClient, mock_studio: MockStudio
  ):
      mock_studio.responder = responder_sequence([("OK", {"path": "event:/a", "bus": "bus:/SFX"})])
      await events.assign_to_bus(client, "event:/a", "bus:/SFX")
      js = _last_sent_js(mock_studio)
      assert "masterTrack.mixerGroup.output" in js