---
name: zambo-receipt
description: "Proves AI work happened: mints and verifies verifiable execution receipts for every AI tool call, one checkable timeline per job. Use when the user asks for proof a call ran, wants to verify an output, asks for an audit trail of agent work, or wants receipts they can show someone else. Built on AER-1, the AI Agent Execution Receipt open draft. A receipt proves the call ran and the output was byte-exact; it never proves the output is correct."
license: MIT
metadata:
  author: zambo.dev
  version: "1.0.0"
  homepage: https://zambo.dev
compatibility: claude, cursor, codex, windsurf, cline
---

# Zambo Receipt

Use this skill when someone needs proof that an AI tool call ran, wants to verify an output, or needs an audit trail they can show to someone else.

## What a receipt is

Every Zambo tool call returns a verifiable receipt with a UUID, tool name, UTC timestamp, SHA-256 hash of the exact output bytes, execution status, and a public verification URL.

## The honesty contract

A receipt proves a specific tool ran with specific inputs at a specific time, and that the quoted output is exactly what came back byte for byte. It does not prove the output is correct, and it does not prove anything outside the recorded call. That boundary is the reason the receipt is useful.

## Mint and verify

Call any Zambo tool. The response includes `_receipt` and a public URL. Open that URL and compare the receipt SHA-256 value against a fresh hash of the returned output bytes.

Whole-job receipts use authenticated `journal_log` plus public run pages. `mode: "verify"` on `zambo_universal` returns a reconstructible step-by-step log.

AER-1 means AI Agent Execution Receipt. It is an open draft RFC, not a finalized standard. Read https://zambo.dev/aer-1/ and https://zambo.dev/execution-receipt/.

## Install

```bash
mkdir -p ~/.claude/skills/receipt && curl -sL https://zambo.dev/skills/receipt/SKILL.md -o ~/.claude/skills/receipt/SKILL.md
```

For the full toolset, also use the flagship skill: https://zambo.dev/skills/zambo/

## References

- Receipt details: https://zambo.dev/skills/receipt/references/receipts.md
- Pricing: https://zambo.dev/skills/zambo/references/pricing.md