ProofSlip

Adds three tools to your MCP client for creating, verifying, and polling ephemeral proof receipts that live for 24 hours. You get create_receipt for logging completed actions or pending approvals, verify_receipt for checking what happened before taking the next step, and check_status for lightweight polling on non-terminal receipts. Useful when you need agents to coordinate on whether an email already sent, an approval cleared, or a retry is safe without building your own state tracking. Requires a ProofSlip API key from their signup endpoint. The receipts include polling guidance and expire automatically, so there's no cleanup work.