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SPOOL

ascribe's edition registry in OP_RETURN, from 2014 to 2017: editions are tokens, pieces are labels, and fuel transactions are enablers.

SPOOL 0.00 % of the chain's bytes in Book A, as of block 972,299, 2026-10-20 09:30:48 UTC

SPOOL is the protocol ascribe used to register and move editions of digital works. In BTI's token table its tokens are SPOOL editions, each identified by an edition id. BTI is its indexer: it is a native protocol, read by BTI's own spool decoder.

How SPOOL writes to Bitcoin #

Every SPOOL operation is a transaction of plain outputs plus an OP_RETURN that names the verb. BTI's SPOOL attribution study (2026-07-29) found two generations.

  • Generation 1 (ASCRIBESPOOL plus a verb, from block 334,920, 2014-12-19). A federation-signed REGISTER pays one 600-sat output per edition, and a TRANSFER pays the new owner and carries ASCRIBESPOOLTRANSFER. There is no edition number in the message.
  • Generation 2 (ASCRIBESPOOL01 plus a verb and its arguments, from block 359,506, 2015-06-05). Outputs of 3,000 sats go to a file-hash address, a piece-hash address and the owner. The message carries an explicit edition number, so which token an operation acts on is read off the chain.

The study dates the last SPOOL bytes to block 490,705 (2017-10-19). The ascribe federation fuelled holders' operations: FUEL and REPLENISH outputs funded the transactions that moved editions.

How BTI attributes its bytes #

The decoder runs in replay mode; the roster notes that edition identity and the fuel graph are both path-dependent. The study proved that an edition transfers by itself, repeatedly: ten editions of one piece moved separately over three years. That makes the edition a token under ruling U3. A piece (PIECE) never moved by itself, so it is a label, a notarization that claims nothing; the adapter rulings count PIECE at 53.7 % of SPOOL's bytes, correctly unclaimed. Ruling B27(1) says LOAN<k> is a transfer, because custody really moves for the term.

SPOOL has no burn mechanism, the study found, and no spend a wallet can make removes an edition. About 99 % of SPOOL outputs are unspent, because about 99 % of editions were never traded.

Fuel, an enabler in the pool #

Case 14 of the BTI case studies is SPOOL fuel. At block 335,677 a 258-byte REPLENISH transaction paid a 20,000-sat fuel output. Three blocks later a 223-byte TRANSFER spent that output to move edition 2 of a piece. The transfer is a dedicated claim over its whole 223 bytes. The fuel transaction carries no claim of its own; it is an enabler, so its bytes join the transfer's pool. The books read content 0, structure 223, overhead 258: Book B = 223 and Book A = 481, with both transactions' 20,000 sats of fees. The enabler's bytes reach Book A only. Only consumed fuel attributes; an unspent fuel output enabled nothing.

The axiom documentation states the consequence: fuelled operations are the sole source of SPOOL's B/A spread, about 0.82 fuelled against about 1.0 elsewhere. The BTI protocol review of 2026-08-29 read SPOOL's B/A as 0.8412 over the whole family. See carriage and the free-ride index.

Live figures #

SPOOL holds 12,550,600 bytes in Book A and 0 in Book C: a ledger operation has no artifact body. The books count 93,692 editions across 99,089 operations, from block 334985 to 541926 (as of block 972,299, 2026-10-20 09:30:48 UTC).

Sources #

  1. block.space docs: the axiom · block.space/docs/axiom
  2. block.space protocols API · block.space/api/protocols
  3. Blockspace Holdings records

Live figures: protocols as of block 972,299, 2026-10-20 09:30:48 UTC. Refreshed hourly.

Updated 2026-10-20 · This page as Markdown