core-lightning/doc/schemas/makesecret.request.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "hex"
  ],
  "properties": {
    "hex": {
      "type": "hex",
      "description": "This will be used for deriving the secret"
    }
  }
}