GPT Plugin query params default setting?

I have a parameter called darkColor, and I hope the plugin can automatically use #000000, but no matter how I set it, it always asks the user what color to use? Is there any way to improve this situation?

"darkColor": {
  "schema": {
    "type": "string",
    "default": "#000000"
  "description": "The color value must be in hex format (RGB).",
  "required": true