The current revision
Read it on the IETF Datatracker: draft-zambo-aer1-26. Revision -26, posted October 22, 2026, is the closing revision of the draft and the one every Zambo package, page, and tool now cites. It expires April 25, 2027. Earlier revisions, including -24 and -25, are superseded: if a page, an answer engine, or a package still cites them, it is citing an old copy, and this page is the pointer to the current one.
What the draft defines
AER-1 defines a small, portable record for one AI agent tool call. In the draft's terms: an agent receipt is a record of one ai agent tool call that anyone can check: it keeps the exact saved bytes and their sha-256 digest, and it proves the result was not changed since it was saved, not that it was right. The draft also states the every-call rule: a receipt issues for every call, including calls that are rejected, so a refusal is a record too, not a gap.
The AER-1 verifier: check a receipt now
The draft is only half the answer; the other half is a verifier anyone can run. The hosted AER-1 verifier at zambo.dev/verify recomputes a receipt's digest and reports the outcome in the browser, free, with no account and no key. The hub's own guides walk the same check step by step: how to verify an AER-1 receipt and verify AI work. Offline, the same check ships as tooling: aer1-verify on PyPI for Python, and the aer-1 package on npm for JavaScript and TypeScript, covered on the npm verifier page. Every verifier is tested against the same public corpus below, so a pass here and a pass offline mean the same thing.
What revision -26 settled
- Merkle versioning (Section 8.1): a workflow close declares its merkle_version, so verifiers recompute the root under the rule the close actually used: seq-output-v1 is current, receipt-id-v0 is legacy, and an absent field reads as v0.
- The verify endpoint (Section 6): the draft cites the /api/v2/ verify endpoint, which returns the evaluated outcome for a receipt; the unversioned endpoint is the deprecated v1.
- Anchor outcomes (Section 6): a fixed vocabulary for reporting a check: verified, verification failed, rejected: unresolvable record, not checked, or absent, so an unevaluated check is never reported as an evaluated one.
AER-1 test vectors: the conformance corpus
The draft's claims are testable against a public corpus: zambo.dev/aer1/corpus.json serves 126 vectors and 129 checks at kit v1.5.7, and independent implementations run the same corpus and publish their results. The reference kit and the verifiers are the fastest way in: the npm verifier for JavaScript, aer1-verify for Python, and the conformance test page for the full suite.
Get receipts on your own agent work
Checking receipts is the second half. The first half is making sure your agents' calls leave one: when a client or a teammate disputes what an agent did, the argument ends where a checkable record begins. Add Zambo and every call your agents run through the endpoint comes back with a verifiable AER-1 receipt at a public link, starting with 20 free calls per day.
Frequently asked questions
What is the current revision of AER-1?
draft-zambo-aer1-26, posted on the IETF Datatracker on October 22, 2026 and expiring April 25, 2027. It is the closing revision: earlier revisions such as -24 and -25 are superseded, and Zambo's packages and pages cite -26.
Who wrote AER-1?
AER-1 was written by Brennan Zambo and published as an IETF Internet-Draft. Independent implementers have since built verifiers and implementations against the public conformance corpus, which is the point of publishing it as an open draft.
Where can I test an implementation against AER-1?
Against the public conformance corpus at zambo.dev/aer1/corpus.json: 126 vectors and 129 checks at kit v1.5.7. The aer-1 npm package and the aer1-verify Python package both run the corpus, and the hub's conformance test page walks through the suite.
What does an AER-1 receipt prove?
An agent receipt is a record of one ai agent tool call that anyone can check: it keeps the exact saved bytes and their sha-256 digest, and it proves the result was not changed since it was saved, not that it was right.
Is AER-1 a finished standard?
No. AER-1 is an Internet-Draft, which is a working document of the IETF, not an RFC. Revision -26 is the current and closing revision of the draft as published; the conformance corpus and the independent implementations are what make its claims checkable today.
What is AER-1?
AER-1 is the agent execution receipt standard published as IETF Internet-Draft draft-zambo-aer1, current revision draft-zambo-aer1-26. It defines a verifiable receipt for one AI agent tool call: a record anyone can check that keeps the exact saved bytes and their SHA-256 digest, and proves the result was not changed since it was saved, not that it was right.
What is the AER-1 verifier?
The AER-1 verifier is the working check for AER-1 receipts. The hosted verifier at zambo.dev/verify recomputes a receipt's digest and reports the outcome in the browser, free, with no account. The same check runs offline with the aer1-verify package on PyPI and the aer-1 package on npm, tested against the AER-1 test vectors in the public corpus.
Where are the AER-1 test vectors?
The AER-1 test vectors are the public conformance corpus at zambo.dev/aer1/corpus.json: 126 vectors and 129 checks at kit v1.5.7. Any implementation can run the corpus locally and compare its results, and independent implementations publish their results against the same vectors.
Related
- AER-1 npm verifier: check a receipt in three lines
- AER-1 Python verifier: aer1-verify on PyPI
- AER-1: the agent execution receipt standard
- AER-1 conformance test: run the suite
- run the AER-1 conformance test: the registry lists the independent implementations and their results.
- Agent execution receipt standard
- How to verify an AER-1 receipt: the AER-1 verifier guide
- Verify AI work: check the record, not the summary
- AER-1 hub: verifiable execution receipts for AI agents
- AER-1 test vectors: the public conformance corpus (JSON)