Agent as an MCP Tool

import { Agent, Cogitator, tool } from '@cogitator-ai/core';
import { MCPClient, serveAgents } from '@cogitator-ai/mcp';
import { z } from 'zod';

const apiKey = process.env.GOOGLE_API_KEY;
if (!apiKey) throw new Error('Set GOOGLE_API_KEY');

const rates: Record<string, number> = { EUR: 0.92, GBP: 0.79, JPY: 151.3 };

const convert = tool({
  name: 'convert_currency',
  description: 'Convert an amount of US dollars into another currency.',
  parameters: z.object({
    amount: z.number().describe('Amount in USD'),
    to: z.enum(['EUR', 'GBP', 'JPY']).describe('Target currency'),
  }),
  execute: async ({ amount, to }) => ({ amount: Math.round(amount * rates[to] * 100) / 100, currency: to }),
});

const cog = new Cogitator({
  llm: { providers: { google: { apiKey } } },
  memory: { adapter: 'memory' },
});

const travel = new Agent({
  name: 'travel_planner',
  description: 'Plans trips and budgets, converting prices between currencies.',
  model: 'google/gemini-3.5-flash-lite',
  instructions: 'You plan trips. Use convert_currency for currency questions. Two sentences at most.',
  tools: [convert],
  temperature: 0.2,
});

const server = await serveAgents(cog, travel, { transport: 'http', host: '127.0.0.1', port: 0 });
const client = await MCPClient.connect({
  transport: 'http',
  url: `http://127.0.0.1:${server.getPort()}/mcp`,
});

try {
  const first = (await client.callTool('travel_planner', {
    task: 'My hotel in Lisbon costs $180 a night. How much is that in euros?',
  })) as { output: string; threadId: string };
  console.log(first.output);

  const followUp = (await client.callTool('travel_planner', {
    task: 'And for 4 nights?',
    threadId: first.threadId,
  })) as { output: string };
  console.log(followUp.output);
} finally {
  await client.close();
  await server.stop();
  await cog.close();
}

pnpm add @cogitator-ai/core @cogitator-ai/mcp zod

GOOGLE_API_KEY=your-key npx tsx agent-as-mcp-server.ts

npx tsx examples/mcp/04-agent-as-mcp-server.ts