object-modify

Object / Modify

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.

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	any	No	Optional. JSON Merge Patch (RFC 7396, extended with [i]/[key] keys) routed through Reflector.TryPatch.