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`	Yes	Find GameObject in opened Prefab or in the active Scene.
`replaceGameObjectWithPrefab`	`boolean`	No	If true, the prefab will replace the GameObject in the scene.

Input JSON Schema

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

Output

Output JSON Schema

{
  "type": "object",
  "properties": {
    "result": {
      "$ref": "#/$defs/com.IvanMurzak.Unity.MCP.Runtime.Data.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."
    }
  },
  "$defs": {
    "System.Type": {
      "type": "string"
    },
    "com.IvanMurzak.Unity.MCP.Runtime.Data.AssetObjectRef": {
      "type": "object",
      "properties": {
        "instanceID": {
          "type": "integer",
          "description": "instanceID of the UnityEngine.Object. If this is '0' and 'assetPath' and 'assetGuid' is not provided, empty or null, then it will be used as 'null'."
        },
        "assetType": {
          "$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"
  ]
}

assets-prefab-create

Assets / Prefab / Create

How to Call