---
title: "tool si.act.undo_merge"
description: "the merge or the decision, and the reason: a parting."
section: reference
address: /reference/tools/si-act-undo_merge
contract: 0476e35e6e275db5
---

# tool si.act.undo_merge

the merge or the decision, and the reason: a parting.

[figure: Over MCP, si.act.undo_merge takes UndoMergeInput and returns a card whose body is UndoMergeAnswer.]

a parting. Or a later decision, with the facts written again. The call needs the act grant at the brand rung.



| | |
|---|---|
| input | [UndoMergeInput](/concepts/undomergeinput) |
| result | a card whose body is [UndoMergeAnswer](/concepts/undomergeanswer) |
| read-only | no |
| destructive | yes |
| card address | `ui://scale-intelligence/cards/UndoMergeAnswer` |
| HTTP route | [`/v1/act/undo_merge`](/reference/act/undo_merge) |





| field | type | required | note |
|---|---|---|---|
| `merge` | `id` | no |  |
| `decision` | `id` | no |  |
| `reason` | `text` | yes |  |