Git File Forensics MCP

Instructions

Implementation Reference

• src/index.ts:323-342 (handler)

  The primary handler function for the 'analyze_file_diff' tool. It retrieves the git diff between two versions, detects moved code blocks, generates a summary, writes the analysis to the specified output path, and returns a success message.
  private async handleFileDiff(args: FileDiffArgs) { const diff = this.getFileDiff(args.repoPath, args.file, args.versions); const movedBlocks = this.findMovedBlocks(diff); const analysis = { diff, movedBlocks, summary: this.generateDiffSummary(diff), }; writeFileSync(args.outputPath, JSON.stringify(analysis, null, 2)); return { content: [ { type: 'text', text: `File diff analysis written to ${args.outputPath}`, }, ], };
• src/index.ts:168-197 (registration)

  Tool registration in the ListTools response, including name, description, and complete input schema definition.
  { name: 'analyze_file_diff', description: 'Analyze specific changes between any two versions of a file', inputSchema: { type: 'object', properties: { repoPath: { type: 'string', description: 'Path to git repository', }, file: { type: 'string', description: 'File to analyze', }, versions: { type: 'object', properties: { from: { type: 'string' }, to: { type: 'string' }, }, required: ['from', 'to'], }, outputPath: { type: 'string', description: 'Path to write analysis output', }, }, required: ['repoPath', 'file', 'versions', 'outputPath'], }, },
• src/index.ts:260-266 (registration)

  Dispatch handler in the CallToolRequestSchema that validates input using isFileDiffArgs and invokes the main handleFileDiff method.
  case 'analyze_file_diff': { const args = request.params.arguments as unknown; if (!this.isFileDiffArgs(args)) { throw new McpError(ErrorCode.InvalidParams, 'Missing required parameters'); } return await this.handleFileDiff(args); }
• src/index.ts:73-90 (schema)

  Type guard function for validating the input arguments against the FileDiffArgs interface used in the tool.
  private isFileDiffArgs(args: unknown): args is FileDiffArgs { return ( typeof args === 'object' && args !== null && 'repoPath' in args && 'file' in args && 'versions' in args && 'outputPath' in args && typeof (args as FileDiffArgs).repoPath === 'string' && typeof (args as FileDiffArgs).file === 'string' && typeof (args as FileDiffArgs).outputPath === 'string' && typeof (args as FileDiffArgs).versions === 'object' && (args as FileDiffArgs).versions !== null && 'from' in (args as FileDiffArgs).versions && 'to' in (args as FileDiffArgs).versions && typeof (args as FileDiffArgs).versions.from === 'string' && typeof (args as FileDiffArgs).versions.to === 'string' );
• src/index.ts:422-431 (helper)

  Helper function that executes the git diff command to retrieve the raw diff between two file versions.
  private getFileDiff( repoPath: string, file: string, versions: { from: string; to: string } ) { return execSync( `cd "${repoPath}" && git diff ${versions.from} ${versions.to} -- "${file}"`, { encoding: 'utf8' } ); }