Trace MCP

Instructions

Implementation Reference

• src/index.ts:69-71 (schema)

  Zod input schema validation for the trace_file tool.

  const TraceFileInput = z.object({
    filePath: z.string().describe('Path to a single TypeScript file to trace tool usage in'),
  });

• src/index.ts:167-177 (registration)

  Tool registration in the listTools handler, defining name, description, and input schema.

  {
    name: 'trace_file',
    description: 'Trace MCP tool usage in a single TypeScript file.',
    inputSchema: {
      type: 'object',
      properties: {
        filePath: { type: 'string', description: 'Path to a TypeScript file' },
      },
      required: ['filePath'],
    },
  },

• src/index.ts:357-375 (handler)

  MCP CallToolRequest handler for 'trace_file': parses input, calls traceFromFile, and formats response.

  case 'trace_file': {
    const input = TraceFileInput.parse(args);
    log(`Tracing file: ${input.filePath}`);
    
    const usage = await traceFromFile(input.filePath);
    
    return {
      content: [
        {
          type: 'text',
          text: JSON.stringify({
            success: true,
            count: usage.length,
            usage,
          }, null, 2),
        },
      ],
    };
  }

• src/trace/index.ts:53-75 (handler)

  Core implementation of traceFromFile: delegates to language-specific parser for the given file.

  export async function traceFromFile(filePath: string, language?: string): Promise<ConsumerSchema[]> {
    // For backward compatibility, default to TypeScript
    const lang = language || 'typescript';
  
    if (!hasParser(lang)) {
      throw new Error(
        `No parser available for language: ${lang}. Make sure to call bootstrapLanguageParsers() at startup.`
      );
    }
  
    const parser = getParser(lang);
  
    // Extract from the directory containing the file
    const rootDir = filePath.substring(0, filePath.lastIndexOf('/') || filePath.lastIndexOf('\\'));
    const fileName = filePath.substring((filePath.lastIndexOf('/') || filePath.lastIndexOf('\\')) + 1);
  
    const allSchemas = await parser.traceUsage({
      rootDir: rootDir || '.',
      include: [fileName],
    });
  
    return allSchemas.filter(s => s.callSite.file === filePath);
  }