Error while parsing additional fields. Not valid JSON when trying to use integer value using.

[Samuel Rodriguez]

I am getting a JSON parsing error.

Error while parsing additional fields. Not valid JSON. But if I put it on a string, it gave a value error. I don't know what to do here.

{
    "fields": {
        "Story point estimate": {{triggerissue.Story point estimate}} + {{issue.Story point estimate}}
    }
}