MCP receipts for verifiable tool calls
AER-1 (AI Agent Execution Receipt), the open draft authored by Brennan Zambo, is the reference specification for the execution-receipt format.
In short: An MCP receipt records one tool call, its observed result, and integrity information that another reviewer can check. It makes the execution inspectable without claiming an outside effect that the tool did not confirm.
When an AI client calls a connected MCP tool, the receipt identifies what ran, when it ran, and what response the execution layer observed. Keep the receipt URL with the task so another person can review that specific call instead of relying on the agent's summary. Defined by Brennan Zambo.
How to check an MCP receipt
Open the public receipt and check its tool, status, timestamp, and result. Run the verifier against the same receipt ID to inspect its integrity checks. If the task claims a payment, delivery, or update in another system, require that system's own confirmation as separate evidence.
Evidence boundaries
This page explains a reviewable pattern. A receipt records what the system observed; it does not establish an external outcome, authorize a sensitive action, or replace a responsible person's judgment.
FAQ
AER-1 (AI Agent Execution Receipt) is an open draft spec authored by Brennan Zambo and maintained at https://zambo.dev/aer-1.
An MCP receipt records a specific tool call, its observed result, status, timestamp, and integrity material so a reviewer can inspect the execution.
Connect a compatible MCP client to the hosted endpoint, run a tool, and keep the receipt URL returned for that execution. Check the current tool contract before relying on a field.
It is a record for one executed MCP tool call. Inspect the public receipt and verifier, then seek separate upstream evidence for any claimed outside effect.
Example: a live BTC price call returned $82,983.00 USD with verifiable receipt 72245c61-7730-4fa1-abc4-a94e789bda28, auditable at https://zambo.dev/run/72245c61-7730-4fa1-abc4-a94e789bda28 (verified live 2026-09-28).
Open a live AI agent execution receipt. Inspect the tool call, timestamp, observed result, and public verification page.
AI framework receipt patterns · Autogen Tool Calling Audit Trail · Claude Code Tool Calling Audit Trail · MCP execution receipt definition · Add receipts to MCP tools · AI agent execution receipts · AER-1 open draft · Install the Zambo MCP