Unity Editor MCP Server

Instructions

Implementation Reference

• Server~/src/tools/menuItemTool.ts:53-73 (handler)

  The core handler function that executes the tool logic: destructures menuPath, sends request to mcpUnity with method 'execute_menu_item', handles response success/error, returns CallToolResult.

  async function toolHandler(mcpUnity: McpUnity, params: any): Promise<CallToolResult> {
    const { menuPath } = params;
    const response = await mcpUnity.sendRequest({
      method: toolName,
      params: { menuPath }
    });
    
    if (!response.success) {
      throw new McpUnityError(
        ErrorType.TOOL_EXECUTION,
        response.message || `Failed to execute menu item: ${menuPath}`
      );
    }
    
    return {
      content: [{
        type: response.type,
        text: response.message || `Successfully executed menu item: ${menuPath}` 
      }]
    };
  }

• Server~/src/tools/menuItemTool.ts:27-42 (registration)

  Registers the 'execute_menu_item' tool with the MCP server using server.tool(), providing name, description, schema, and a wrapper handler that calls the core toolHandler.

  server.tool(
    toolName,
    toolDescription,
    paramsSchema.shape,
    async (params: any) => {
      try {
        logger.info(`Executing tool: ${toolName}`, params);
        const result = await toolHandler(mcpUnity, params);
        logger.info(`Tool execution successful: ${toolName}`);
        return result;
      } catch (error) {
        logger.error(`Tool execution failed: ${toolName}`, error);
        throw error;
      }
    }
  );

• Server~/src/tools/menuItemTool.ts:11-13 (schema)

  Zod schema defining the single input parameter 'menuPath' as a string with description.

  const paramsSchema = z.object({
    menuPath: z.string().describe('The path to the menu item to execute (e.g. "GameObject/Create Empty")')
  });

• Server~/src/index.ts:54-54 (registration)

  Calls the registerMenuItemTool function to register the tool during server initialization.

  registerMenuItemTool(server, mcpUnity, toolLogger);