---
name: assets-prefab-save
description: Save the currently opened prefab edit stage back to its prefab asset without exiting the stage. Pair with 'assets-prefab-open' to enter the edit mode first.
---

# Assets / Prefab / Save

Save a prefab. Use it when you are in prefab editing mode in Unity Editor. Use 'assets-prefab-open' tool to open a prefab first.

## Behavior

Calls `PrefabUtility.SaveAsPrefabAsset` on the current prefab stage's contents root, clears the stage's dirtiness flag, repaints editor windows, and returns an `AssetObjectRef` to the saved prefab. Throws when no prefab stage is currently open.

## How to Call

```bash
unity-mcp-cli run-tool assets-prefab-save --input '{
  "nothing": "string_value"
}'
```

> For complex input (multi-line strings, code), save the JSON to a file and use:
> ```bash
> unity-mcp-cli run-tool assets-prefab-save --input-file args.json
> ```
>
> Or pipe via stdin (recommended):
> ```bash
> unity-mcp-cli run-tool assets-prefab-save --input-file - <<'EOF'
> {"param": "value"}
> EOF
> ```


### Troubleshooting

If `unity-mcp-cli` is not found, either install it globally (`npm install -g unity-mcp-cli`) or use `npx unity-mcp-cli` instead.
Read the /unity-initial-setup skill for detailed installation instructions.

## Input

| Name | Type | Required | Description |
|------|------|----------|-------------|
| `nothing` | `string` | No |  |

### Input JSON Schema

```json
{
  "type": "object",
  "properties": {
    "nothing": {
      "type": "string"
    }
  }
}
```

## Output

### Output JSON Schema

```json
{
  "type": "object",
  "properties": {
    "result": {
      "$ref": "#/$defs/AIGD.AssetObjectRef",
      "description": "Reference to UnityEngine.Object asset instance. It could be Material, ScriptableObject, Prefab, and any other Asset. Anything located in the Assets and Packages folders."
    }
  },
  "$defs": {
    "System.Type": {
      "type": "string"
    },
    "AIGD.AssetObjectRef": {
      "type": "object",
      "properties": {
        "instanceID": {
          "type": "integer",
          "description": "instanceID of the UnityEngine.Object. If this is '0' and 'assetPath' and 'assetGuid' is not provided, empty or null, then it will be used as 'null'."
        },
        "assetType": {
          "$ref": "#/$defs/System.Type",
          "description": "Type of the asset."
        },
        "assetPath": {
          "type": "string",
          "description": "Path to the asset within the project. Starts with 'Assets/'"
        },
        "assetGuid": {
          "type": "string",
          "description": "Unique identifier for the asset."
        }
      },
      "required": [
        "instanceID"
      ],
      "description": "Reference to UnityEngine.Object asset instance. It could be Material, ScriptableObject, Prefab, and any other Asset. Anything located in the Assets and Packages folders."
    }
  },
  "required": [
    "result"
  ]
}
```