IICS: How to increase string precision in business services response fields

Question

I have an API call which returns a very very long string, its size is around 885412 characters. But right now I can only capture the first 255 characters of it due to some reasons.

Like as you can see from the picture below, when I hang over my mouse on the response field 'result', it shows that its type is string and its precision is 255, I guess this is the reason.

If so, how can I capture the long string completely? Is there any way to increase the precision of this 'result' field?

Below is how I wrote my swagger file now, should I define something to increase the max length here?

"definitions" : { 
"sg_response": {
  "properties": {
    "result": {
      "type" : "string"
    }
  }
}

}

Thank you so much for your help!