For agents

Agents that pay for themselves

An agent can use Screwtape.ai with no person in the loop. It can create a free API key, or pay per call in USDC with x402 and no key at all.

x402 per call

0.005 USDC per judge or consensus call on Base (eip155:8453) or Solana. Send the call with no API key. The response is HTTP 402 with the x402 payment requirements: scheme, network, amount, asset and payTo. The agent signs a payment for exactly those terms and retries with the PAYMENT-SIGNATURE header. On Solana, payTo is the wallet owner and the USDC goes to that owner's associated token account for the mint. Solana is listed in the 402 when that payee is set.

Where the payee address lives. Always take payTo from the live 402 response. The same value is published in /pricing.json and /agents.md. We do not print the wallet on marketing pages, so check the 402 rather than an address copied from anywhere else.

Prepaid USDC packs

• Starter: 10,000 prepaid calls for $40 USD, paid in USDC on Base or Solana.
• Builder: 50,000 prepaid calls for $175 USD, paid in USDC on Base or Solana.

A pack page shows the exact payee before the wallet signs. Pay with PayPal (card) is on the pricing page.

Read next

• /agents.md: the full guide for an AI agent, with networks, assets and payees.
• API docs and OpenAPI.
• Terms and privacy notice.