| name | object-modify |
| description | Modify the specified Unity Object. Allows direct modification of object fields and properties. Use 'object-get-data' first to inspect the object structure before modifying.
Three modification surfaces (use whichever fits the task):
1. 'objectDiff' — full SerializedMember diff (legacy, backwards compatible).
2. 'pathPatches' — list of {path, value} pairs routed through Reflector.TryModifyAt; atomic per-path modification, multiple entries can target different depths.
3. 'jsonPatch' — a JSON Merge Patch (RFC 7396, extended with [i]/[key] notation) routed through Reflector.TryPatch; multiple fields at any depth in a single call.
When more than one is supplied they run in this order: jsonPatch → pathPatches → objectDiff. At least one is required.
Path syntax: 'fieldName', 'nested/field', 'arrayField/[i]', 'dictField/[key]'. Leading '#/' is stripped. |
Object / Modify
How to Call
unity-mcp-cli run-tool object-modify --input '{
"objectRef": "string_value",
"objectDiff": "string_value",
"pathPatches": "string_value",
"jsonPatch": "string_value"
}'
For complex input (multi-line strings, code), save the JSON to a file and use:
unity-mcp-cli run-tool object-modify --input-file args.json
Or pipe via stdin (recommended):
unity-mcp-cli run-tool object-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 |
|---|
objectRef | any | Yes | Reference to UnityEngine.Object instance. It could be GameObject, Component, Asset, etc. Anything extended from UnityEngine.Object. |
objectDiff | any | No | Optional. The full object data to apply (legacy path). Should contain 'fields' and/or 'props' with the values to modify. |
| Only include the fields/properties you want to change. | | | |
| Any unknown or invalid fields and properties will be reported in the response. | | | |
pathPatches | any | No | Optional. List of path-scoped patches routed through Reflector.TryModifyAt. |
jsonPatch | string | No | Optional. JSON Merge Patch (RFC 7396, extended with [i]/[key] keys) routed through Reflector.TryPatch. |
Input JSON Schema
{
"type": "object",
"properties": {
"objectRef": {
"$ref": "#/$defs/com.IvanMurzak.Unity.MCP.Runtime.Data.ObjectRef"
},
"objectDiff": {
"$ref": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember"
},
"pathPatches": {
"$ref": "#/$defs/System.Collections.Generic.List<com.IvanMurzak.Unity.MCP.Runtime.Data.PathPatch>"
},
"jsonPatch": {
"type": "string"
}
},
"$defs": {
"com.IvanMurzak.Unity.MCP.Runtime.Data.ObjectRef": {
"type": "object",
"properties": {
"instanceID": {
"type": "integer",
"description": "instanceID of the UnityEngine.Object. If this is '0', then it will be used as 'null'."
}
},
"required": [
"instanceID"
],
"description": "Reference to UnityEngine.Object instance. It could be GameObject, Component, Asset, etc. Anything extended from UnityEngine.Object."
},
"com.IvanMurzak.ReflectorNet.Model.SerializedMemberList": {
"type": "array",
"items": {
"$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": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember",
"description": "Nested property value."
},
"description": "Properties of the object, serialized as a list of 'SerializedMember'."
}
},
"required": [
"typeName"
],
"additionalProperties": false
},
"com.IvanMurzak.Unity.MCP.Runtime.Data.PathPatch": {
"type": "object",
"properties": {
"Path": {
"type": "string",
"description": "Slash-delimited path to the target field/element/entry. Plain segment navigates a field or property (e.g. 'admin' or 'admin/name'). Use '[i]' for array/list index (e.g. 'planets/[0]/orbitRadius'). Use '[key]' for dictionary entry (e.g. 'config/[timeout]'). A leading '#/' is stripped automatically. Required."
},
"Value": {
"$ref": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember",
"description": "The new value to write at the path. Use the standard SerializedMember envelope: 'typeName' + 'value' for primitives, or nested 'fields'/'props' for complex types. Required — omitting it overwrites the target with a default empty SerializedMember."
}
}
},
"System.Collections.Generic.List<com.IvanMurzak.Unity.MCP.Runtime.Data.PathPatch>": {
"type": "array",
"items": {
"$ref": "#/$defs/com.IvanMurzak.Unity.MCP.Runtime.Data.PathPatch"
}
}
},
"required": [
"objectRef"
]
}
Output
Output JSON Schema
{
"type": "object",
"properties": {
"result": {
"$ref": "#/$defs/com.IvanMurzak.Unity.MCP.Editor.API.Tool_Object+ModifyObjectResponse"
}
},
"$defs": {
"com.IvanMurzak.Unity.MCP.Runtime.Data.ObjectRef": {
"type": "object",
"properties": {
"instanceID": {
"type": "integer",
"description": "instanceID of the UnityEngine.Object. If this is '0', then it will be used as 'null'."
}
},
"required": [
"instanceID"
],
"description": "Reference to UnityEngine.Object instance. It could be GameObject, Component, Asset, etc. Anything extended from UnityEngine.Object."
},
"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
},
"com.IvanMurzak.ReflectorNet.Model.SerializedMemberList": {
"type": "array",
"items": {
"$ref": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember"
}
},
"System.String[]": {
"type": "array",
"items": {
"type": "string"
}
},
"com.IvanMurzak.Unity.MCP.Editor.API.Tool_Object+ModifyObjectResponse": {
"type": "object",
"properties": {
"Success": {
"type": "boolean",
"description": "Whether the modification was successful."
},
"Reference": {
"$ref": "#/$defs/com.IvanMurzak.Unity.MCP.Runtime.Data.ObjectRef",
"description": "Reference to the modified object."
},
"Data": {
"$ref": "#/$defs/com.IvanMurzak.ReflectorNet.Model.SerializedMember",
"description": "Updated object data after modification."
},
"Logs": {
"$ref": "#/$defs/System.String[]",
"description": "Log of modifications made and any warnings/errors encountered."
}
},
"required": [
"Success"
]
}
},
"required": [
"result"
]
}
