Zambo This document specifies AER-1, a small vocabulary for recording one AI agent tool call as a portable, independently checkable execution receipt. A receipt identifies the execution, records when it happened, preserves the canonical bytes used for the output commitment, names the tool and caller scope, carries a provenance class, and resolves at a stable public URL. The format separates what the system observed from claims about the outside world, and it separates provenance (who ran or reported the action) from the record itself. A reference implementation is deployed, and its receipts are publicly verifiable without an account or token.