MCP Server for Unity

Instructions

Implementation Reference

• src/tools/unity-mcp-tools.ts:366-377 (handler)

  Handler for script_apply_diff tool: validates input, calls adapter.applyDiff, and returns formatted success response with stats.

  case 'script_apply_diff': {
    if (!args.path || !args.diff) {
      throw new Error('path and diff are required');
    }
    const result = await this.adapter.applyDiff(args.path, args.diff, args.options);
    return {
      content: [{
        type: 'text',
        text: `Diff applied successfully:\nPath: ${result.path}\nLines added: ${result.linesAdded}\nLines removed: ${result.linesRemoved}`
      }]
    };
  }

• src/tools/unity-mcp-tools.ts:113-140 (registration)

  Tool registration including name, description, and input schema definition for script_apply_diff.

  {
    name: 'script_apply_diff',
    description: 'Apply a unified diff to a C# script',
    inputSchema: {
      type: 'object',
      properties: {
        path: {
          type: 'string',
          description: 'Path to the script file'
        },
        diff: {
          type: 'string',
          description: 'Unified diff content to apply'
        },
        options: {
          type: 'object',
          description: 'Optional diff application settings',
          properties: {
            dryRun: {
              type: 'boolean',
              description: 'Preview changes without applying (default: false)'
            }
          }
        }
      },
      required: ['path', 'diff']
    }
  },

• src/adapters/unity-http-adapter.ts:130-132 (helper)

  Helper method in UnityHttpAdapter that proxies the diff application request to Unity HTTP server endpoint.

  async applyDiff(path: string, diff: string, options?: any): Promise<any> {
    return this.call('script/applyDiff', { path, diff, options });
  }