assets-modify

name	assets-modify
description	Modify asset file in the project. Use 'assets-get-data' tool first to inspect the asset structure before modifying. Not allowed to modify asset file in 'Packages/' folder. Please modify it in 'Assets/' folder.

Assets / Modify

How to Call

unity-mcp-cli run-tool assets-modify --input '{
  "assetRef": "string_value",
  "content": "string_value"
}'

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

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

Or pipe via stdin (recommended):

unity-mcp-cli run-tool assets-modify --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
assetRef	any	Yes	Reference to UnityEngine.Object asset instance. It could be Material, ScriptableObject, Prefab, and any other Asset. Anything located in the Assets and Packages folders.
content	any	Yes	The asset content. It overrides the existing asset content.

Input JSON Schema

{
  "type": "object",
  "properties": {
    "assetRef": {
      "$ref": "#/$defs/com.IvanMurzak.Unity.MCP.Runtime.Data.AssetObjectRef"
    },
    "content": {
      "$ref": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember"
    }
  },
  "$defs": {
    "System.Type": {
      "type": "string"
    },
    "com.IvanMurzak.Unity.MCP.Runtime.Data.AssetObjectRef": {
      "type": "object",
      "properties": {
        "instanceID": {
          "type": "integer",
          "description": "instanceID of the UnityEngine.Object. If this is '0' and 'assetPath' and 'assetGuid' is not provided, empty or null, then it will be used as 'null'."
        },
        "assetType": {
          "$ref": "#/$defs/System.Type",
          "description": "Type of the asset."
        },
        "assetPath": {
          "type": "string",
          "description": "Path to the asset within the project. Starts with 'Assets/'"
        },
        "assetGuid": {
          "type": "string",
          "description": "Unique identifier for the asset."
        }
      },
      "required": [
        "instanceID"
      ],
      "description": "Reference to UnityEngine.Object asset instance. It could be Material, ScriptableObject, Prefab, and any other Asset. Anything located in the Assets and Packages folders."
    },
    "com.IvanMurzak.ReflectorNet.Model.SerializedMemberList": {
      "type": "array",
      "items": {
        "$ref": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember"
      }
    },
    "com.IvanMurzak.ReflectorNet.Model.SerializedMember": {
      "type": "object",
      "properties": {
        "typeName": {
          "type": "string",
          "description": "Full type name. Eg: 'System.String', 'System.Int32', 'UnityEngine.Vector3', etc."
        },
        "name": {
          "type": "string",
          "description": "Object name."
        },
        "value": {
          "description": "Value of the object, serialized as a non stringified JSON element. Can be null if the value is not set. Can be default value if the value is an empty object or array json."
        },
        "fields": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember",
            "description": "Nested field value."
          },
          "description": "Fields of the object, serialized as a list of 'SerializedMember'."
        },
        "props": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember",
            "description": "Nested property value."
          },
          "description": "Properties of the object, serialized as a list of 'SerializedMember'."
        }
      },
      "required": [
        "typeName"
      ],
      "additionalProperties": false
    }
  },
  "required": [
    "assetRef",
    "content"
  ]
}

Output

Output JSON Schema

{
  "type": "object",
  "properties": {
    "result": {
      "$ref": "#/$defs/System.String[]"
    }
  },
  "$defs": {
    "System.String[]": {
      "type": "array",
      "items": {
        "type": "string"
      }
    }
  },
  "required": [
    "result"
  ]
}