agentic-debugger

#!/usr/bin/env node import { Server } from '@modelcontextprotocol/sdk/server/index.js'; import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js'; import { CallToolRequestSchema, ListToolsRequestSchema, } from '@modelcontextprotocol/sdk/types.js'; import { SessionManager } from './session.js'; import { Instrumenter } from './instrumenter.js'; // Use current working directory for the debug session const workingDirectory = process.cwd(); const sessionManager = new SessionManager(workingDirectory); let instrumenter: Instrumenter | null = null; const server = new Server( { name: 'agentic-debugger', version: '1.0.0', }, { capabilities: { tools: {}, }, } ); // List available tools server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools: [ { name: 'start_debug_session', description: 'Start a debug session. This starts a local HTTP server to receive logs from instrumented code.', inputSchema: { type: 'object', properties: { port: { type: 'number', description: 'Port number for the debug server (default: 9876)', default: 9876, }, }, }, }, { name: 'stop_debug_session', description: 'Stop the current debug session and shut down the log server.', inputSchema: { type: 'object', properties: {}, }, }, { name: 'add_instrument', description: 'Add a debug instrument at a specific line in a file. The instrument will log variable values when executed.', inputSchema: { type: 'object', properties: { file: { type: 'string', description: 'Path to the file to instrument (relative to working directory)', }, line: { type: 'number', description: 'Line number where to insert the instrument (1-indexed)', }, capture: { type: 'array', items: { type: 'string' }, description: 'Variable names to capture and log', default: [], }, }, required: ['file', 'line'], }, }, { name: 'remove_instruments', description: 'Remove debug instruments from files.', inputSchema: { type: 'object', properties: { file: { type: 'string', description: 'Path to file to remove instruments from. If not specified, removes from all instrumented files.', }, }, }, }, { name: 'list_instruments', description: 'List all active debug instruments.', inputSchema: { type: 'object', properties: {}, }, }, { name: 'read_debug_logs', description: 'Read the collected debug logs from the current session.', inputSchema: { type: 'object', properties: { format: { type: 'string', enum: ['raw', 'pretty'], description: 'Output format (default: pretty)', default: 'pretty', }, }, }, }, { name: 'clear_debug_logs', description: 'Clear all collected debug logs.', inputSchema: { type: 'object', properties: {}, }, }, ], }; }); // Handle tool calls server.setRequestHandler(CallToolRequestSchema, async (request) => { const { name, arguments: args } = request.params; try { switch (name) { case 'start_debug_session': { const port = (args?.port as number) || 9876; const session = await sessionManager.startSession(port); instrumenter = new Instrumenter(port); return { content: [ { type: 'text', text: `Debug session started!\n\nSession ID: ${session.id}\nServer: http://localhost:${port}\nLog file: ${session.logFile}\n\nYou can now add instruments to capture variable values.`, }, ], }; } case 'stop_debug_session': { if (!sessionManager.isActive()) { return { content: [{ type: 'text', text: 'No active debug session to stop.' }], }; } // Remove all instruments from files before stopping const instruments = sessionManager.getInstruments(); if (instrumenter) { for (const instrument of instruments) { instrumenter.removeInstrument(instrument); } } await sessionManager.stopSession(); instrumenter = null; return { content: [ { type: 'text', text: `Debug session stopped. Removed ${instruments.length} instrument(s) from code.`, }, ], }; } case 'add_instrument': { if (!sessionManager.isActive() || !instrumenter) { return { content: [{ type: 'text', text: 'No active debug session. Start one first with start_debug_session.' }], isError: true, }; } const file = args?.file as string; const line = args?.line as number; const capture = (args?.capture as string[]) || []; if (!file || !line) { return { content: [{ type: 'text', text: 'Missing required parameters: file and line' }], isError: true, }; } const instrument = sessionManager.addInstrument({ file, line, capture }); instrumenter.addInstrument(instrument); return { content: [ { type: 'text', text: `Instrument added!\n\nID: ${instrument.id}\nFile: ${instrument.file}\nLine: ${line}\nCapturing: ${capture.length > 0 ? capture.join(', ') : '(no variables)'}\n\nThe instrument will log data when that line is executed.`, }, ], }; } case 'remove_instruments': { if (!sessionManager.isActive() || !instrumenter) { return { content: [{ type: 'text', text: 'No active debug session.' }], isError: true, }; } const file = args?.file as string | undefined; if (file) { // Remove from specific file const instruments = sessionManager.getInstrumentsByFile(file); for (const instrument of instruments) { instrumenter.removeInstrument(instrument); sessionManager.removeInstrument(instrument.id); } return { content: [ { type: 'text', text: `Removed ${instruments.length} instrument(s) from ${file}`, }, ], }; } else { // Remove from all files const instruments = sessionManager.getInstruments(); for (const instrument of instruments) { instrumenter.removeInstrument(instrument); } sessionManager.clearInstruments(); return { content: [ { type: 'text', text: `Removed ${instruments.length} instrument(s) from all files`, }, ], }; } } case 'list_instruments': { const instruments = sessionManager.getInstruments(); if (instruments.length === 0) { return { content: [{ type: 'text', text: 'No active instruments.' }], }; } const list = instruments .map((i) => `- ${i.id}: ${i.file}:${i.line} [${i.capture.join(', ') || 'no capture'}]`) .join('\n'); return { content: [ { type: 'text', text: `Active instruments (${instruments.length}):\n\n${list}`, }, ], }; } case 'read_debug_logs': { if (!sessionManager.isActive()) { return { content: [{ type: 'text', text: 'No active debug session.' }], isError: true, }; } const format = (args?.format as string) || 'pretty'; const logs = sessionManager.readLogs(); if (!logs.trim()) { return { content: [ { type: 'text', text: 'No logs collected yet. Make sure to reproduce the bug to trigger the instruments.', }, ], }; } if (format === 'raw') { return { content: [{ type: 'text', text: logs }], }; } // Pretty format const entries = logs .trim() .split('\n') .map((line) => { try { return JSON.parse(line); } catch { return null; } }) .filter(Boolean); const formatted = entries .map((entry, i) => { const time = new Date(entry.timestamp).toISOString(); const data = JSON.stringify(entry.data, null, 2); return `[${i + 1}] ${time}\nInstrument: ${entry.id}\nLocation: ${entry.location}\nData:\n${data}`; }) .join('\n\n---\n\n'); return { content: [ { type: 'text', text: `Debug logs (${entries.length} entries):\n\n${formatted}`, }, ], }; } case 'clear_debug_logs': { if (!sessionManager.isActive()) { return { content: [{ type: 'text', text: 'No active debug session.' }], isError: true, }; } sessionManager.clearLogs(); return { content: [{ type: 'text', text: 'Debug logs cleared.' }], }; } default: return { content: [{ type: 'text', text: `Unknown tool: ${name}` }], isError: true, }; } } catch (error) { const message = error instanceof Error ? error.message : String(error); return { content: [{ type: 'text', text: `Error: ${message}` }], isError: true, }; } }); // Start the server async function main() { const transport = new StdioServerTransport(); await server.connect(transport); console.error('Agentic Debugger MCP server running'); } main().catch(console.error);