BIP 347 — OP_CAT in Tapscript

BIP 347 (OP_CAT in Tapscript) proposes re-enabling the concatenation opcode (disabled by Satoshi in 2010) within tapscript via an OP_SUCCESS redefinition. Concatenation composes with other script features to enable covenant-style constructions and other introspection tricks. Repository status: Complete — the specification is finished; it is not activated and there is no scheduled deployment.

⚠️ Time-sensitive — not re-verified since `asOf` (2026-07-22). The spec description above is canonical; the deployment clause is not. "It is not activated and there is no scheduled deployment" is a live status for one of the two headline covenant candidates — the exact sentence a debate leans on, and the exact sentence an activation push would falsify. asOf records the last verification (the BIP header was checked 2026-07-22), not the last edit — any editing since then left the date unchanged because it added no re-verification of activation status. Re-verify the current repository status and any scheduled deployment against the BIPs repository before repeating either on stage.

Debate relevance: One of the two headline covenant candidates (with CTV). Debates cover both technical scope ('what can CAT actually do?') and process ('is Complete a step toward activation?'). Common misstatements: "OP_CAT is Complete, so it's basically in" — Complete describes the specification document, not consensus adoption; activation is a separate, contested process. "Satoshi removed OP_CAT because of covenants" — the 2010 disabling addressed memory/DoS concerns; covenant implications are a modern analysis.