Vercel Serverless Calculator Agent

A serverless calculator API powered by SpinAI that performs mathematical operations using a natural language interface.

Project Structure

• api/ - Contains serverless function endpoints
• actions/ - Contains calculator operations (sum, minus, multiply, divide)
• dev-server.ts - Local development server that mimics Vercel's serverless environment

Development

Local Development Options

Option 1: Custom Dev Server (Recommended)

Our custom development server mimics Vercel's serverless environment but with better debugging capabilities and no timeout issues:

npm run dev

This starts a server at http://localhost:3000 that:

• Automatically discovers all API endpoints in the api/ directory
• Maps /api/endpoint and /endpoint to the corresponding handlers
• Provides detailed error messages for debugging

Option 2: Vercel Dev

You can also use Vercel's official development environment:

npm run vercel-dev
# or
vercel dev

Testing Your API

Send a POST request to your API endpoint:

curl -X POST http://localhost:3000/api -H "Content-Type: application/json" -d '{"input": "5+7"}'

Example request body:

{
  "input": "5+7"
}

Example response:

{
  "response": {
    "finalNumber": 12
  },
  "messages": [...]
}

Deployment

Configuration

Before deploying, ensure your vercel.json file is properly configured:

{
  "version": 2,
  "functions": {
    "api/**/*.ts": {
      "maxDuration": 60
    }
  }
}

IMPORTANT: The maxDuration setting is crucial for preventing logging timeouts. The default 10-second timeout is often not enough for SpinAI agents to complete execution and send logs properly.

Environment Variables

Set these environment variables in your Vercel project:

• SPINAI_API_KEY - Your SpinAI API key
• LOGGING_PUBLIC_URL - (Optional) Public endpoint for logs

Deploy to Vercel

vercel deploy
# or for production
vercel deploy --prod

Your API will be accessible at:

https://your-project-name.vercel.app/api

Troubleshooting

Empty Log Bodies

If you're experiencing empty log bodies in your logging endpoint:

1. Increase function timeout: Ensure maxDuration is set to at least 60 seconds in vercel.json
2. Check connection closure: Vercel may close connections before logs are fully transmitted (see issue: denoland/deno#27132)
3. Error handling: The code includes special handling for BadResource errors that occur when connections close prematurely

Testing Locally vs Production

If your function works locally but fails in production:

1. Check environment variables in Vercel dashboard
2. Ensure maxDuration is properly set in vercel.json
3. Look for timeout errors in Vercel function logs