diligence/test/mcp-client.mjs

#!/usr/bin/env node
/**
 * MCP Test Client
 *
 * Programmatically tests the diligence MCP server by:
 * 1. Spawning the server as a child process
 * 2. Sending JSON-RPC messages via stdio
 * 3. Receiving and parsing responses
 *
 * Usage:
 *   const client = new McpClient();
 *   await client.connect();
 *   const result = await client.callTool('status', {});
 *   await client.disconnect();
 */

import { spawn } from 'child_process';
import { createInterface } from 'readline';
import { dirname, join } from 'path';
import { fileURLToPath } from 'url';

const __dirname = dirname(fileURLToPath(import.meta.url));

export class McpClient {
  constructor(serverPath = join(__dirname, '..', 'index.mjs')) {
    this.serverPath = serverPath;
    this.process = null;
    this.requestId = 0;
    this.pendingRequests = new Map();
    this.readline = null;
  }

  async connect() {
    return new Promise((resolve, reject) => {
      this.process = spawn('node', [this.serverPath], {
        stdio: ['pipe', 'pipe', 'pipe'],
        cwd: join(__dirname, 'fixture'),  // Run in fixture directory
      });

      this.readline = createInterface({
        input: this.process.stdout,
        crlfDelay: Infinity,
      });

      this.readline.on('line', (line) => {
        try {
          const message = JSON.parse(line);
          if (message.id !== undefined && this.pendingRequests.has(message.id)) {
            const { resolve, reject } = this.pendingRequests.get(message.id);
            this.pendingRequests.delete(message.id);
            if (message.error) {
              reject(new Error(message.error.message || JSON.stringify(message.error)));
            } else {
              resolve(message.result);
            }
          }
        } catch (e) {
          // Ignore non-JSON lines
        }
      });

      this.process.stderr.on('data', (data) => {
        // Server logs to stderr
        if (process.env.DEBUG) {
          console.error('[server]', data.toString());
        }
      });

      this.process.on('error', reject);
      this.process.on('exit', (code) => {
        if (code !== 0 && code !== null) {
          console.error(`Server exited with code ${code}`);
        }
      });

      // Initialize the MCP connection
      this._send({
        jsonrpc: '2.0',
        id: this.requestId++,
        method: 'initialize',
        params: {
          protocolVersion: '0.1.0',
          clientInfo: { name: 'test-client', version: '1.0.0' },
          capabilities: {},
        },
      }).then(() => {
        // Send initialized notification
        this._sendNotification('notifications/initialized', {});
        resolve();
      }).catch(reject);
    });
  }

  async disconnect() {
    if (this.process) {
      this.process.kill('SIGTERM');
      this.process = null;
    }
    if (this.readline) {
      this.readline.close();
      this.readline = null;
    }
  }

  _send(message) {
    return new Promise((resolve, reject) => {
      if (!this.process) {
        reject(new Error('Not connected'));
        return;
      }
      this.pendingRequests.set(message.id, { resolve, reject });
      this.process.stdin.write(JSON.stringify(message) + '\n');

      // Timeout after 10 seconds
      setTimeout(() => {
        if (this.pendingRequests.has(message.id)) {
          this.pendingRequests.delete(message.id);
          reject(new Error('Request timeout'));
        }
      }, 10000);
    });
  }

  _sendNotification(method, params) {
    if (!this.process) return;
    this.process.stdin.write(JSON.stringify({
      jsonrpc: '2.0',
      method,
      params,
    }) + '\n');
  }

  async listTools() {
    const result = await this._send({
      jsonrpc: '2.0',
      id: this.requestId++,
      method: 'tools/list',
      params: {},
    });
    return result.tools;
  }

  async callTool(name, args = {}) {
    const result = await this._send({
      jsonrpc: '2.0',
      id: this.requestId++,
      method: 'tools/call',
      params: { name, arguments: args },
    });
    // Extract text from content array
    if (result.content && result.content[0] && result.content[0].text) {
      return {
        text: result.content[0].text,
        isError: result.isError || false,
      };
    }
    return result;
  }

  // Convenience methods for common workflows
  async status() {
    return this.callTool('status');
  }

  async start(task) {
    return this.callTool('start', { task });
  }

  async propose(proposal) {
    return this.callTool('propose', { proposal });
  }

  async review(decision, reasoning) {
    return this.callTool('review', { decision, reasoning });
  }

  async getWorkerBrief() {
    return this.callTool('get_worker_brief');
  }

  async getReviewerBrief() {
    return this.callTool('get_reviewer_brief');
  }

  async implement() {
    return this.callTool('implement');
  }

  async complete(summary) {
    return this.callTool('complete', { summary });
  }

  async abort(reason) {
    return this.callTool('abort', { reason });
  }

  async approve(reason) {
    return this.callTool('approve', { reason });
  }
}

// CLI usage for quick testing
if (process.argv[1] === fileURLToPath(import.meta.url)) {
  const client = new McpClient();

  try {
    console.log('Connecting to MCP server...');
    await client.connect();
    console.log('Connected!\n');

    // List tools
    const tools = await client.listTools();
    console.log('Available tools:');
    tools.forEach(t => console.log(`  - ${t.name}: ${t.description.slice(0, 60)}...`));
    console.log();

    // Check status
    const status = await client.status();
    console.log('Status:');
    console.log(status.text);

    await client.disconnect();
    console.log('\nDisconnected.');
  } catch (err) {
    console.error('Error:', err.message);
    await client.disconnect();
    process.exit(1);
  }
}