D&D MCP Server

Instructions

Implementation Reference

• src/gamemaster_mcp/main.py:561-589 (handler)

  MCP tool handler for 'update_game_state'. Defines input schema via Annotated parameters with Field descriptions and constraints. Collects provided kwargs and delegates to storage.update_game_state. Returns confirmation message. The @mcp.tool decorator handles registration.

  @mcp.tool
  def update_game_state(
      current_location: Annotated[str | None, Field(description="Current party location")] = None,
      current_session: Annotated[int | None, Field(description="Current session number", ge=1)] = None,
      current_date_in_game: Annotated[str | None, Field(description="Current in-game date")] = None,
      party_level: Annotated[int | None, Field(description="Average party level", ge=1, le=20)] = None,
      party_funds: Annotated[str | None, Field(description="Party treasure/funds")] = None,
      in_combat: Annotated[bool | None, Field(description="Whether party is in combat")] = None,
      notes: Annotated[str | None, Field(description="Current situation notes")] = None,
  ) -> str:
      """Update the current game state."""
      kwargs = {}
      if current_location is not None:
          kwargs["current_location"] = current_location
      if current_session is not None:
          kwargs["current_session"] = current_session
      if current_date_in_game is not None:
          kwargs["current_date_in_game"] = current_date_in_game
      if party_level is not None:
          kwargs["party_level"] = party_level
      if party_funds is not None:
          kwargs["party_funds"] = party_funds
      if in_combat is not None:
          kwargs["in_combat"] = in_combat
      if notes is not None:
          kwargs["notes"] = notes
  
      storage.update_game_state(**kwargs)
      return "Updated game state"

• src/gamemaster_mcp/storage.py:380-392 (helper)

  Storage class method that implements the actual game state update logic by dynamically setting attributes on the GameState object based on kwargs, updating timestamps, and persisting to file.

  def update_game_state(self, **kwargs) -> None:
      """Update the game state."""
      if not self._current_campaign:
          raise ValueError("No current campaign")
  
      game_state = self._current_campaign.game_state
      for key, value in kwargs.items():
          if hasattr(game_state, key):
              setattr(game_state, key, value)
  
      game_state.updated_at = datetime.now()
      self._current_campaign.updated_at = datetime.now()
      self._save_campaign()