Audio Playback MCP Server

Instructions

Implementation Reference

• src/audio_playback_server/server.py:24-87 (handler)

  The `audio_playback` tool handler is defined using the `@server.tool` decorator within `_build_server`. It processes playback actions by delegating to an `AudioPlaybackManager` instance.

  @server.tool(
      name="audio_playback",
      description=(
          "Control playback of local audio files for automated testing. Audio is "
          "played via a virtual audio output device that is routed into the Android "
          "emulator's microphone. Use this to simulate a human speaking into the mic "
          "by playing prerecorded files."
      ),
  )
  async def audio_playback(
      action: Literal["play", "stop", "pause", "resume", "status", "list_files"],
      filename: Optional[str] = None,
      start_offset_ms: int = 0,
      list_limit: int = 200,
  ) -> dict:
      if action == "play" and (filename is None or not filename.strip()):
          return {
              "success": False,
              "message": "filename is required for 'play' action.",
              "state": manager.state,
          }
  
      if start_offset_ms < 0:
          return {
              "success": False,
              "message": "start_offset_ms must be non-negative.",
              "state": manager.state,
          }
  
      try:
          if action == "play":
              success, message, state = await manager.play(
                  filename=filename or "",
                  start_offset_ms=start_offset_ms,
              )
              return {"success": success, "message": message, "state": state}
  
          if action == "stop":
              success, message, state = await manager.stop()
              return {"success": success, "message": message, "state": state}
  
          if action == "pause":
              success, message, state = await manager.pause()
              return {"success": success, "message": message, "state": state}
  
          if action == "resume":
              success, message, state = await manager.resume()
              return {"success": success, "message": message, "state": state}
  
          if action == "status":
              success, message, state = await manager.status()
              return {"success": success, "message": message, "state": state}
  
          files_payload = manager.list_local_files(limit=list_limit)
          return {
              "success": True,
              "message": "Listed files available under AUDIO_ROOT_DIR.",
              "state": manager.state,
              "files": files_payload,
          }
      except ValueError as exc:
          return {"success": False, "message": str(exc), "state": manager.state}
  
  return server