COINTELEGRAPH · 2026-11-11 13:26 UTC

Bitcoin Covenants Part 5: MATT and OP_CHECKCONTRACTVERIFY — How Bitcoin could carry state across transaction

MATT (Merkleize All The Things) is a smart contract framework for Bitcoin enabling stateful contracts and scalable fraud proofs, where state carries across transactions. The article says existing covenant proposals like Sapio (built on OP_CTV) represent state as a finite state automaton, whereas MATT, via OP_CCV, lets committed data be computed at spend time and re-embedded into the next output. OP_CCV tweaks a Taproot internal key with a hash of the current state, and the article describes default, deduct, and ignore modes for checking outputs, with fees paid through separate inputs.

Loading the story on Tree News…