OP_CAT in Tapscript

The five-minute read

One action, walked through

1. Open BIP 347 and read the status line before the examples.
2. Write down the rule in one sentence. A fair version of that sentence is: OP_CAT as a tapscript opcode which allows the concatenation of two values on the stack.
3. Name the object that changes: OP_CAT, OP_SUCCESS126, UNIX.
4. Ask what an old client, an old contract, or an offline counterparty does. If the document is silent, the silence is part of the design.

The argument, unpacked

What has to be true

• You are implementing BIP 347 at the status the text itself states: Complete.
• The object that has to change is OP_CAT, OP_SUCCESS126, UNIX. A neighbouring document with a similar name is not this one.
• This page is not a guide to moving funds.

What happened after the paper

The source marks this complete. That is a statement about the text, not a promise that every wallet or node has shipped it. Later documents can narrow, replace, or ignore this one. Cite the number you mean.

What to check before you use the idea

• What is the timeout in OP_CAT in Tapscript, and who can take the coins when it expires?
• Which chain, if any, adjudicates the dispute?
• Which fields are committed: OP_CAT, OP_SUCCESS126, UNIX?

Terms

BIP 347

The public text titled OP_CAT in Tapscript.

Complete

The document's own label for how finished the text is. It is not a market fact.

The problem the paper names

A payment or a bridge that cannot name the dispute path is a custodial promise with extra steps.

What the design proposes

• OP_CAT as a tapscript opcode which allows the concatenation of two values on the stack.
• OP_CAT would be activated via a soft fork by redefining the opcode OP_SUCCESS126 (126 in decimal and 0x7e in hexadecimal).
• This is the same opcode value used by the original OP_CAT.

How the mechanism is specified

• Taken from the specification, the next constraint is: OP_CAT would be activated via a soft fork by redefining the opcode OP_SUCCESS126 (126 in decimal and 0x7e in hexadecimal).
• Locate OP_CAT, OP_SUCCESS126, UNIX in BIP 347 and apply it to one transaction or call.
• Then check the failure the class of rule always has: a node that did not upgrade, a reverted call, a replayed signature, or a peer that does not speak the message.

What this page does not treat as proven

• A specification of a hash lock is not a working route, and not a guarantee the counterparty is online.
• This page is not a guide to moving funds.
• The source marks this complete. That is a statement about the text, not a promise that every wallet or node has shipped it.

Why a venture studio still reads it

Use BIP 347 when a pitch says 'OP_CAT in Tapscript' without saying whether the rule is consensus, policy, or an interface. The number is the citation. The pitch is not.