# Harn agents protocol receipt format

> The canonical receipt-format artifact lives in agents-protocol-receipts .

Website: https://harnlang.com/spec/agents-protocol/receipt-format-v1.html

This page documents Harn, which is pre-1.0. Language, standard library, and CLI APIs may change. If the intended version is unclear, clarify before using this page.

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The canonical receipt-format artifact lives in
[`agents-protocol-receipts`](../../../../spec/agents-protocol/receipts/README.md).

It defines the `receipt-2026-04-25` JSON envelope, JSON Schema, fixtures,
canonicalization and hash rules, optional CBOR archive encoding, and OpenAPI
component reference for `Receipt` resources.

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## Read next

- [Agents Protocol v1](https://harnlang.com/spec/agents-protocol/v1.md)
- [Agents Protocol replay contract](https://harnlang.com/spec/agents-protocol/replay-v1.md)