Assets / Prefab / Create

Create a prefab from a GameObject in the current active scene. The prefab will be saved in the project assets at the specified path. Creates folders recursively if they do not exist. If the source GameObject is already a prefab instance and 'connectGameObjectToPrefab' is true, a Prefab Variant is created automatically. To create a Prefab Variant from an existing prefab asset, provide 'sourcePrefabAssetPath' instead of 'gameObjectRef'. Use 'gameobject-find' tool to find the target GameObject first.

Inputs (mutually exclusive sources)

• prefabAssetPath — required. Must start with Assets/ and end with .prefab.
• gameObjectRef — scene GameObject to convert (or to seed a Prefab Variant from when it is already a prefab instance).
• sourcePrefabAssetPath — existing prefab asset to seed a Prefab Variant from. Cannot be combined with gameObjectRef.
• connectGameObjectToPrefab (default true) — when sourcing from a scene GameObject, connect the scene object to the new prefab asset (becoming a prefab instance). Ignored for sourcePrefabAssetPath (always creates a variant).

Behavior

Creates intermediate folders along prefabAssetPath if they don't already exist. Returns an AssetObjectRef pointing at the new prefab asset.

How to Call

unity-mcp-cli run-tool assets-prefab-create --input '{
  "prefabAssetPath": "string_value",
  "gameObjectRef": "string_value",
  "sourcePrefabAssetPath": "string_value",
  "connectGameObjectToPrefab": false
}'

For complex input (multi-line strings, code), save the JSON to a file and use:

unity-mcp-cli run-tool assets-prefab-create --input-file args.json

Or pipe via stdin (recommended):

unity-mcp-cli run-tool assets-prefab-create --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
prefabAssetPath	string	Yes	Prefab asset path. Should be in the format 'Assets/Path/To/Prefab.prefab'.
gameObjectRef	any	No	Reference to a scene GameObject to create the prefab from. If the GameObject is already a prefab instance, a Prefab Variant is created when 'connectGameObjectToPrefab' is true. Optional if 'sourcePrefabAssetPath' is provided.
sourcePrefabAssetPath	string	No	Path to an existing prefab asset to create a Prefab Variant from (e.g. 'Assets/Prefabs/Base.prefab'). When provided, a temporary instance is created, saved as a Prefab Variant, and cleaned up. Optional if 'gameObjectRef' is provided.
connectGameObjectToPrefab	boolean	No	If true, the scene GameObject will be connected to the new prefab (becoming a prefab instance). If the source is already a prefab instance, this creates a Prefab Variant. If false, the prefab asset is created but the scene GameObject remains unchanged. Ignored when 'sourcePrefabAssetPath' is used (always creates a variant).

Input JSON Schema

{
  "type": "object",
  "properties": {
    "prefabAssetPath": {
      "type": "string"
    },
    "gameObjectRef": {
      "$ref": "#/$defs/AIGD.GameObjectRef"
    },
    "sourcePrefabAssetPath": {
      "type": "string"
    },
    "connectGameObjectToPrefab": {
      "type": "boolean"
    }
  },
  "$defs": {
    "System.Type": {
      "type": "string"
    },
    "AIGD.GameObjectRef": {
      "type": "object",
      "properties": {
        "instanceID": {
          "type": "integer",
          "description": "instanceID of the UnityEngine.Object. If it is '0' and 'path', 'name', 'assetPath' and 'assetGuid' is not provided, empty or null, then it will be used as 'null'. Priority: 1 (Recommended)"
        },
        "path": {
          "type": "string",
          "description": "Path of a GameObject in the hierarchy Sample 'character/hand/finger/particle'. Priority: 2."
        },
        "name": {
          "type": "string",
          "description": "Name of a GameObject in hierarchy. Priority: 3."
        },
        "assetType": {
          "$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": "Find GameObject in opened Prefab or in the active Scene."
    }
  },
  "required": [
    "prefabAssetPath"
  ]
}

Output

Output JSON Schema

{
  "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"
  ]
}