A Minibits token could not be redeemed on framework-pt: the mint answered
POST /v1/swap with a bare 422, which the RPC sanitizer turned into
"Operation failed. Check server logs for details." The journal had the
real reason:
inputs[0].id: NUT02: ID length invalid, expected 8 bytes (short/v1)
or 33 bytes (v2)
The token carried keyset id 01fc0ec0e59cd6fa — exactly the first 8 bytes
of the mint's active 33-byte id 01fc0ec0e59cd6fa01b7a88f…a821. NUT-02 v2
ids are 33 bytes behind a 0x01 version byte; the sending wallet cut it to
the 8 bytes that were the whole id under v1. The mint reads the version,
expects 33 bytes, and rejects it — so the length complaint is right even
though 8 bytes is legal for a 0x00-prefixed v1 id.
The id only names which keyset signed a proof, and the short form is a
prefix of the full one, so it can be repaired: before swapping, any
8-byte 0x01-prefixed id is expanded against GET /v1/keysets (new
MintClient::get_keysets — it lists inactive keysets too, and coins from a
retired keyset stay spendable). Preferring the active keyset on a prefix
tie. Attempting this is safe: an id naming the wrong keyset fails
signature verification at the mint and no coins move. Anything already
valid, or with no unambiguous match, is passed through so the mint's own
error still reaches the operator.
Token decoding now also checks keyset ids locally, so an id that is not
hex or is neither NUT-02 length fails with a message naming the format
instead of a raw 422 from the mint.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
