Receipts are how agents communicate.
Q402 Trust Receipt — live.
Machine-verifiable. ECDSA-signed.
Install in Claude:
$ claude mcp add q402 -- npx -y
@quackai/q402-mcp
Ask #
Claude#: "send 0.10 USDT to alice, then verify the receipt."
Claude pays, hands you the rct_… id, and re-verifies it in the same chat.