MCP GDB Server

Instructions

Implementation Reference

• src/index.ts:1068-1109 (handler)

  Core handler function for the 'gdb_examine' tool. It validates the session, constructs the GDB examine command 'x/{count}{format} {expression}', executes it, and formats the response.
  private async handleGdbExamine(args: any) { const { sessionId, expression, format = 'x', count = 1 } = args; if (!activeSessions.has(sessionId)) { return { content: [ { type: 'text', text: `No active GDB session with ID: ${sessionId}` } ], isError: true }; } const session = activeSessions.get(sessionId)!; try { // Format examine command: x/[count][format] [expression] const command = `x/${count}${format} ${expression}`; const output = await this.executeGdbCommand(session, command); return { content: [ { type: 'text', text: `Examine ${expression} (format: ${format}, count: ${count}):\n\n${output}` } ] }; } catch (error) { const errorMessage = error instanceof Error ? error.message : String(error); return { content: [ { type: 'text', text: `Failed to examine memory: ${errorMessage}` } ], isError: true }; }
• src/index.ts:312-332 (schema)

  Input schema definition for the gdb_examine tool, specifying required sessionId and expression, optional format and count.
  inputSchema: { type: 'object', properties: { sessionId: { type: 'string', description: 'GDB session ID' }, expression: { type: 'string', description: 'Memory address or expression' }, format: { type: 'string', description: 'Display format (e.g., "x" for hex, "i" for instruction)' }, count: { type: 'number', description: 'Number of units to display' } }, required: ['sessionId', 'expression']
• src/index.ts:309-334 (registration)

  Tool registration in the ListToolsRequestSchema handler, defining name, description, and inputSchema for gdb_examine.
  { name: 'gdb_examine', description: 'Examine memory', inputSchema: { type: 'object', properties: { sessionId: { type: 'string', description: 'GDB session ID' }, expression: { type: 'string', description: 'Memory address or expression' }, format: { type: 'string', description: 'Display format (e.g., "x" for hex, "i" for instruction)' }, count: { type: 'number', description: 'Number of units to display' } }, required: ['sessionId', 'expression'] } },
• src/index.ts:387-388 (registration)

  Dispatch registration in the CallToolRequestSchema switch statement, routing gdb_examine calls to the handler.
  case 'gdb_examine': return await this.handleGdbExamine(request.params.arguments);
• src/index.ts:1159-1217 (helper)

  Shared helper function that executes GDB commands over stdin/stdout and captures/parses the output, used by gdb_examine handler.
  private executeGdbCommand(session: GdbSession, command: string): Promise<string> { return new Promise<string>((resolve, reject) => { if (!session.ready) { reject(new Error('GDB session is not ready')); return; } // Write command to GDB's stdin if (session.process.stdin) { session.process.stdin.write(command + '\n'); } else { reject(new Error('GDB stdin is not available')); return; } let output = ''; let responseComplete = false; // Create a one-time event handler for GDB output const onLine = (line: string) => { output += line + '\n'; // Check if this line indicates the end of the GDB response if (line.includes('(gdb)') || line.includes('^done') || line.includes('^error')) { responseComplete = true; // If we've received the complete response, resolve the promise if (responseComplete) { // Remove the listener to avoid memory leaks session.rl.removeListener('line', onLine); resolve(output); } } }; // Add the line handler to the readline interface session.rl.on('line', onLine); // Set a timeout to prevent hanging const timeout = setTimeout(() => { session.rl.removeListener('line', onLine); reject(new Error('GDB command timed out')); }, 10000); // 10 second timeout // Handle GDB errors const errorHandler = (data: Buffer) => { const errorText = data.toString(); output += `[stderr] ${errorText}\n`; }; // Add error handler if (session.process.stderr) { session.process.stderr.once('data', errorHandler); } // Clean up event handlers when the timeout expires timeout.unref(); }); }