MCP Server for Unity

Instructions

Implementation Reference

• src/tools/unity-mcp-tools.ts:340-351 (handler)

  Handler for script_read tool: validates input path, calls adapter.readScript, formats and returns the script content.

  case 'script_read': {
    if (!args.path) {
      throw new Error('path is required');
    }
    const result = await this.adapter.readScript(args.path);
    return {
      content: [{
        type: 'text',
        text: `Script content from ${result.path}:\n\n${result.content}`
      }]
    };
  }

• src/tools/unity-mcp-tools.ts:85-98 (schema)

  Input schema definition for the script_read tool, specifying the required 'path' parameter.

  {
    name: 'script_read',
    description: 'Read a C# script from Unity project',
    inputSchema: {
      type: 'object',
      properties: {
        path: {
          type: 'string',
          description: 'Path to the script file'
        }
      },
      required: ['path']
    }
  },

• src/simple-index.ts:35-37 (registration)

  Registers the tool list handler which includes script_read via UnityMcpTools.getTools().

  this.server.setRequestHandler(ListToolsRequestSchema, async () => ({
    tools: this.tools.getTools(),
  }));

• src/adapters/unity-http-adapter.ts:122-124 (helper)

  Adapter helper method that sends HTTP POST request to Unity server's 'script/read' endpoint.

  async readScript(path: string): Promise<any> {
    return this.call('script/read', { path });
  }

• src/embedded-scripts.ts:400-416 (helper)

  Unity C# implementation (embedded): reads script file content from disk in worker thread for 'script/read' endpoint.

  static object ReadScriptOnWorkerThread(JObject request)
  {
      var path = request["path"]?.ToString();
      if (string.IsNullOrEmpty(path))
          throw new ArgumentException("path is required");
      
      var fullPath = Path.Combine(Application.dataPath, path.Substring(ASSETS_PREFIX_LENGTH));
      if (!File.Exists(fullPath))
          throw new FileNotFoundException($"File not found: {path}");
      
      return new
      {
          path = path,
          content = File.ReadAllText(fullPath, new UTF8Encoding(true)),
          guid = "" // GUID requires AssetDatabase, skip in worker thread
      };
  }