Verifiable receipts for AI agents
For developers
A verifiable receipt for an AI agent is a record, made by the execution layer rather than the agent, of one tool call: the tool, its inputs, the observed result, a SHA-256 hash of the request and a timestamp, published at a URL anyone can check.
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For developers
Zambo is the verifiable work layer for AI. Give your AI hands: one hosted MCP at https://zambo.dev/api/mcp, no key, no signup, 20 total free calls per day across work tools. Every job returns a receipt at https://zambo.dev/run/<uuid>, checkable at https://zambo.dev/verify.
see a real receipt · check a receipt.
Frequently asked questions
How is a receipt different from an agent's log?
A log is the agent's own story. A receipt is written by the system that ran the call, so the agent can't edit it after the fact.
How do I check a receipt?
For developers
Open the /run/<uuid> link or paste it into https://zambo.dev/verify. Then spot-check the result in the real system.
Do receipts carry across AIs?
Yes. Cross-AI continuity: a session started in Claude can be continued in ChatGPT or Cursor, and every receipt stays checkable.
What does it cost?
For developers
Free: 20 total free calls per day across work tools. Agents can buy a 24-hour Day Pass, $0.99 USDC on Base via x402 (POST /api/x402/day-pass), then send the X-Zambo-Key header. It isn't billed per call. People: Zambo Pass, $29 for 30 days or $250 once for current Level 2 while Zambo operates, or See pricing for 30 days for eligible $ZAMBO holders. No subscription. No automatic renewal.