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.
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.jsonOr pipe via stdin (recommended):
unity-mcp-cli run-tool assets-modify --input-file - <<'EOF' {"param": "value"} EOF
If unity-mcp-cli is not found, either install it globally () or use instead.
Read the /unity-initial-setup skill for detailed installation instructions.
npm install -g unity-mcp-clinpx unity-mcp-cli| 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. |
{
"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": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember",
"description": "Nested property value."
},
"description": "Properties of the object, serialized as a list of 'SerializedMember'."
}
},
"required": [
"typeName"
],
"additionalProperties": false
}
},
"required": [
"assetRef",
"content"
]
}
{
"type": "object",
"properties": {
"result": {
"$ref": "#/$defs/System.String[]"
}
},
"$defs": {
"System.String[]": {
"type": "array",
"items": {
"type": "string"
}
}
},
"required": [
"result"
]
}