Agent Loop

Demonstrates an agent making multiple sequential paid API calls with a low balance warning.

What it does

1. Creates a Crumb instance with a lowBalanceThreshold of 0.5 USDC
2. Iterates through 5 different search queries
3. Makes a paid POST /search request for each query
4. Prints result counts and payment amounts for each call
5. Shows the final balance after all queries complete

Source

import { Crumb } from 'crumb-alpha-sdk'

const crumb = new Crumb({
  privateKey: process.env.TEST_PRIVATE_KEY!,
  chain: 'arcTestnet',
  lowBalanceThreshold: 0.5,
  onLowBalance: (balance) => {
    console.warn(`[WARNING] Low balance: ${balance} USDC — consider topping up`)
  },
})

const queries = [
  'machine learning optimization techniques',
  'distributed systems consensus algorithms',
  'zero knowledge proof applications',
  'autonomous agent architectures 2025',
  'quantum computing error correction',
]

async function main() {
  console.log('Agent address:', crumb.address)
  console.log('Starting balance:', await crumb.balance(), 'USDC')

  for (const query of queries) {
    console.log(`Querying: "${query}"`)

    try {
      const result = await crumb.fetch('http://localhost:3001/search', {
        method: 'POST',
        body: { query },
        maxPayment: 0.01,
      })

      console.log(`  Results: ${(result.data as any)?.results?.length ?? 0} items`)
      console.log(`  Paid: ${result.formattedAmount} USDC`)
    } catch (err: any) {
      console.error(`  Error: ${err.message}`)
      break
    }
  }

  console.log('Final balance:', await crumb.balance(), 'USDC')
}

main().catch(console.error)

Running

Requires a provider running on port 3001.

# Terminal 1
npx tsx --env-file=.env examples/provider-express/index.ts

# Terminal 2
npx tsx --env-file=.env examples/agent-loop/index.ts

Expected output

Agent address: 0x22b2...
Starting balance: 10.0 USDC

Querying: "machine learning optimization techniques"
  Results: 3 items
  Paid: 0.001 USDC

Querying: "distributed systems consensus algorithms"
  Results: 3 items
  Paid: 0.001 USDC

...

Final balance: 9.995 USDC

If the balance drops below 0.5 USDC during the loop, you'll see the low balance warning.