/history

name: unity-history
description: Manage undo/redo history over the native undo stack

History Skills

Undo, redo and inspect the current undo group of the Unity Editor's native undo stack. Parameters come from the schema (`GET /skills/schema?names=<skill>&wire=v2`); execution and dryRun rules: root [SKILL.md](../../SKILL.md).

The skills are defined in `WorkflowSkills.cs` (category Workflow) and documented here as well as in the [workflow](../workflow/SKILL.md) module.

When to use

• Reviewing or navigating undo history
• Stepping undo and redo
• Auditing what changed

Rules

• `history_get_current` is read-only and runs under Approval. `history_undo` and `history_redo` change scene state and need a grant under Approval.
• `history_undo` and `history_redo` replay Unity's own native undo stack. Its entries cannot be classified by write category the way workflow task snapshots can, so they carry no payload-level `SURFACE_EXCLUDED` check. [workflow](../workflow/SKILL.md) undo (`workflow_undo_task`, `workflow_session_undo`) does carry that check.
• For persistent task-level or conversation-level undo, use the [workflow](../workflow/SKILL.md) module. For simple undo and redo, the [editor](../editor/SKILL.md) skills `editor_undo` and `editor_redo` are the alternative.

Pitfalls

• `history_list` and `history_get` do not exist: use `history_get_current` for the current undo group.
• `history_clear` does not exist, and no skill clears the undo history. Unity exposes `Undo.ClearAll()` (this repository's prefab tests call it, `Tests/Editor/Core/PrefabAssetEditingTests.cs:32`), but no skill wraps it.
• `history_save` does not exist: Unity manages the undo history automatically.

Skills

history_undo

Undo the last operation (or multiple steps).

| Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | steps | int | No | 1 | Number of undo steps to perform |

**Returns:** `{ success, undoneSteps }`

history_redo

Redo the last undone operation (or multiple steps).

| Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | steps | int | No | 1 | Number of redo steps to perform |

**Returns:** `{ success, redoneSteps }`

history_get_current

Get the name of the current undo group.

No parameters.

**Returns:** `{ success, currentGroup, groupIndex }`