Next.js Route Handler

easy10 minapp/api/chat/route.ts

You want a streaming chat endpoint in a Next.js App Router project.

What it shows

Export createChatHandler() as POST from a route file
Authenticate in beforeRun and log usage in afterRun

The code

app/api/chat/route.ts

import { Agent, Cogitator, calculator } from '@cogitator-ai/core';
import { createChatHandler } from '@cogitator-ai/next';

const cogitator = new Cogitator({
  llm: { providers: { google: { apiKey: process.env.GOOGLE_API_KEY ?? '' } } },
  memory: { adapter: 'memory' },
});

const agent = new Agent({
  name: 'assistant',
  model: 'google/gemini-3.5-flash-lite',
  instructions: 'You are a helpful assistant. Use tools when appropriate. Be concise.',
  tools: [calculator],
  temperature: 0.3,
});

export const POST = createChatHandler(cogitator, agent, {
  beforeRun: async (req) => {
    const auth = req.headers.get('authorization');
    if (!auth) throw new Error('Unauthorized');
    return { userId: auth };
  },
  afterRun: async (result) => {
    console.log(`Tokens used: ${result.usage.totalTokens}`);
  },
});

Run it

install · bash

pnpm add @cogitator-ai/core @cogitator-ai/next

EnvironmentGOOGLE_API_KEY

run · bash

pnpm next dev   # GOOGLE_API_KEY in .env.local

The repo file is a reference for a Next.js project, not a script you run on its own.

Next.js Route Handler

What it shows

The code

Run it

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