# Agent Commerce Kit (ACK) ACK

[7 · Pay](/category/pay/)

| Agent Commerce Kit (ACK) |
| --- |
| Category | [Pay](/category/pay/) |
| Governed by | Developed by Catena Labs and contributed as MIT-licensed open source (agentcommercekit/ack); no standards body |
| Status | Open protocols with no stated version, status or date on the concepts page; reference packages tagged up to agentcommercekit@0.11.0 |
| Phase | draft |
| Implementation | prototype |
| Adoption | unmeasured |
| Version | unversioned docs; reference packages agentcommercekit@0.11.0 (2026-10-16) |
| Specification | [https://www.agentcommercekit.com/overview/concepts](https://www.agentcommercekit.com/overview/concepts) |
| Found at | none at a fixed path; identity rests on DIDs and verifiable credentials exchanged between the parties |
| Acronym collisions | ACK (TCP acknowledgement, unrelated), Not one of the protocols called ACP |
| Last checked | 2026-10-20 |
| Freshness | current · checked 2026-10-20 |
| Solves | Accept payments from agents, Prove an agent's identity, Let agents buy on behalf of a person |

Agent Commerce Kit (ACK) is an agentic-web standard (document format) at step 7, Pay, governed by Developed by Catena Labs and contributed as MIT-licensed open source (agentcommercekit/ack); its own status is "Open protocols with no stated version, status or date on the concepts page; reference packages tagged up to agentcommercekit@0.11.0" (draft). It answers: How can an agent prove who owns it and pay another party, on any rail, with a receipt both sides can verify? Adoption is unmeasured, last verified 2026-10-20.

[Pay](/category/pay/) Agent Commerce Kit (ACK) is Catena Labs' set of open patterns for agent identity and agent payments, with reference code [[1]](#ref-1)[[2]](#ref-2). ACK-ID gives an agent a DID and verifiable credentials that trace it back to its owner [[1]](#ref-1). ACK-Pay covers starting a payment, issuing a verifiable receipt and settling on whichever rail the parties use, card or stablecoin among them; it supports x402 [[1]](#ref-1).

## Overview
Catena Labs launched it in May 2025 and contributed it as MIT-licensed open source [[1]](#ref-1)[[3]](#ref-3). The docs give no version, status or date. The reference packages are tagged up to agentcommercekit@0.11.0 and the code is still active [[2]](#ref-2). ACK defines nothing at a fixed path on an origin. Its payment half is filed under Pay; ACK-ID would also fit under Identify.

## Discovery and probe

none at a fixed path; identity rests on DIDs and verifiable credentials exchanged between the parties

```
GET none — no fixed path defined
parse:     No artefact at a fixed path to parse.
on absent: Not probeable from an origin.
```

Not probed live: no-fixed-path. ACK identity and payment objects are exchanged between parties; no fixed path is defined.

## History
- 2026-10-20 — added from gap scout 2026-10-20; verified against agentcommercekit.com/overview/concepts and github.com/agentcommercekit/ack

## Instances

No instances recorded yet.

## See also

- Not to be confused with: ACK (TCP acknowledgement, unrelated), Not one of the protocols called ACP

## References

- The ACK concepts page describes Agent Commerce Kit as open protocols: ACK-ID for agent identity and ownership chains built on DIDs and verifiable credentials, and ACK-Pay for payment initiation, verifiable receipts and settlement-agnostic flows that support x402; it says Catena Labs initially developed it and contributed it as MIT-licensed open source, and gives no version, status or date. — [https://www.agentcommercekit.com/overview/concepts](https://www.agentcommercekit.com/overview/concepts) VERIFIED
- The agentcommercekit/ack repository is MIT licensed, created 2025-05-19 and last pushed 2026-10-16, with package tags up to agentcommercekit@0.11.0. — [https://github.com/agentcommercekit/ack](https://github.com/agentcommercekit/ack) (2026-10-16) VERIFIED
- Business Wire carries Catena Labs' launch announcement of Agent Commerce Kit. — [https://www.businesswire.com/news/home/20250520361792/en/](https://www.businesswire.com/news/home/20250520361792/en/) (2025-05-20) REPORTED

[JSON](/data/protocols/agent-commerce-kit.json) · [Markdown](/protocols/agent-commerce-kit/index.md)