<p>OP_CAT on its own has limited applicability to the lightning routed payment network itself - it cannot be used to build <a href="https://bitcoinops.org/en/topics/eltoo/" rel="nofollow noreferrer">Lightning Symmetry</a> channels. It could be used to potentially reduce the number of transactions needed in resolving lightning penalty without incurring additional round-trips, but the cost of the CAT script and required witness data would likely exceed the savings in transaction inputs and outputs.</p>
<p>However, <a href="https://bitcoin.stackexchange.com/questions/123829/how-can-op-cat-be-used-to-implement-additional-covenants">OP_CAT covenants</a> can be used to enable building improved end user experiences linked to the lightning network, such as <a href="https://github.com/JohnLaw2/ln-scaling-covenants/blob/main/scalingcovenants_v1.3.pdf" rel="nofollow noreferrer">timeout trees</a>, <a href="https://arkdev.info/" rel="nofollow noreferrer">Ark</a>, and potentially <a href="https://bitcoinops.org/en/topics/channel-factories/" rel="nofollow noreferrer">channel factories</a>.</p>

CC BY-SA 4.0
2024-08-22T17:11:03.220Z
So to be clear, you are not aware of a way to use OP_CAT to clearly improve lightning today?
Murch
CC BY-SA 4.0
2024-08-21T19:46:50.170Z
2024-08-21T19:46:50.170Z
Brandon - Rearden
<p>In a debate about OP_CAT, it was claimed without further evidence that the addition of the OP_CAT opcode would &quot;improve Lightning&quot;. Could you expound how OP_CAT would improve lightning?</p>

<lightning-network><bip347-op-cat>
How does the addition of OP_CAT improve Lightning?
Murch
# How does the addition of OP_CAT improve Lightning?

(Asked by: username_0 on 2024-08-21)

In a debate about OP\_CAT, it was claimed without further evidence that the addition of the OP\_CAT opcode would "improve Lightning". Could you expound how OP\_CAT would improve lightning?

**Tags:** lightning-network, bip347-op-cat


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## 1 answers

### Answer by username_1 on 2024-08-21. Score: 1

OP\_CAT on its own has limited applicability to the lightning routed payment network itself - it cannot be used to build [Lightning Symmetry](https://bitcoinops.org/en/topics/eltoo/) channels. It could be used to potentially reduce the number of transactions needed in resolving lightning penalty without incurring additional round-trips, but the cost of the CAT script and required witness data would likely exceed the savings in transaction inputs and outputs.

However, [OP\_CAT covenants](https://bitcoin.stackexchange.com/questions/123829/how-can-op-cat-be-used-to-implement-additional-covenants) can be used to enable building improved end user experiences linked to the lightning network, such as [timeout trees](https://github.com/JohnLaw2/ln-scaling-covenants/blob/main/scalingcovenants_v1.3.pdf), [Ark](https://arkdev.info/), and potentially [channel factories](https://bitcoinops.org/en/topics/channel-factories/).

> **Comments:**
> **username_0**: So to be clear, you are not aware of a way to use OP_CAT to clearly improve lightning today?  

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