Receipts

Verify what was bound and signed. What a receipt binds, how to check its signature against a key you pin, and what a valid receipt does not prove.

A receipt binds input, checks, evidence, decision, and software version.

excellent-mcp receipt verify <pack.json> --pubkey <key.pem>

Expected result: one JSON line reporting whether the canonical payload hash and the Ed25519 signature match, and whether the pack anchors to the key you pinned. Exit codes: 0 verified, 2 usage, 8 unverifiable or invalid.

Pin the key yourself. A receipt re-signed under an attacker's key, handed to you with that attacker's key, verifies exactly as cleanly as a genuine one. See a real receipt and a real tamper being caught on Sample receipt.

The format itself is published: Receipt format has the JSON Schema, an example pack and a zero-dependency verifier you can run on a machine that has never had Excellent installed.

A receipt does not prove every external source was truthful. It proves which records were bound and signed together.

If verification fails, do not rely on the result until the digest or signing key issue is resolved.