Below worked for me to transition and add internal comment

function Add-InternalComment {
    param (
        [string]$IssueKey,
        [string]$Comment,
        [string]$TransitionId = "181"  # Default transition ID
    )

    # Define the URL for the transitions endpoint
    $transitionUrl = "https://xxxxx.atlassian.net/rest/api/2/issue/$IssueKey/transitions"

    # Get the authentication headers
    $headers = Get-JiraAuthHeader

    # Prepare the body for the transition request
    $body = @{
        update = @{
            comment = @(
                @{
                    add = @{
                        body = $Comment
                        properties = @(
                            @{
                                key = "sd.public.comment"
                                value = @

                            }
                        )
                    }
                }
            )
        }
        transition = @

    } | ConvertTo-Json -Depth 10 -Compress

    try

catch

}

Jumping in here, as I'm also trying to do something similar. I am using the Jira Automation block called "Transition Issue." My workflow is configured to require a comment when transitioned between a specific status. This automation block, I'm sure it using an API call on the backend.

As a result to use this automation block I MUST provide a comment. However, I'd like that comment to be an "internal note" on a JSM project. I've tried multiple iterations of JSON blobs using the "More Options" config of the automation block, but have yet to be able to get the comment to be an internal one.

JSON Blob attempt #1

{
    "update": {
        "comment": [
            {
                "add": {
                    "body": "My comment body here.",
                    "public": false
                }
            }
        ]
    }
} 

JSON Blob attempt #2

{
    "update": {
        "comment": [
            {
                "add": {
                    "body": "My comment body here",
                    "properties": [
                        {
                            "key": "sd.public.comment",
                            "value": {
                                "internal": true
                            }
                        }
                    ]
                }
            }
        ]
    }
} 

According to https://community.atlassian.com/t5/Jira-questions/add-a-comment-while-changing-issue-status-by-REST/qaq-p/590930, "You can only add a comment while transitioning by REST if you require a comment for transitioning in UI".  Maybe change the transition to require a comment first?

I am trying to use the "Do Transition" API https://<host>/rest/api/2/issue/<issue>/transitions

See https://docs.atlassian.com/software/jira/docs/api/REST/8.4.2/#api/2/issue-doTransition

For testing, I am using body:

{
  "update": {
    "comment": [
      {
        "add": {
          "body": "This is a comment"
        }
      }
    ]
  },
  "transition": {
    "id": "31"
  }

}

The problem is that the comment is not added to the issue. While the transition does happen.

You need to have this body, sorry for the one line formatting:
{"body": {"type": "doc","version": 1,
"content": [{"type": "paragraph","content": [

]}]},
"properties": \\{"key": "sd.public.comment","value": {"internal": true}}
}

Hi Michael, did you try to use a Transitionscreen and having the comment on it ?

For me this works.

But still fighting to be able to set the internal comment.

BR

Heiko Gerlach

NEXUS AG

Any update on this? You still cannot post a comment when doing a transition using v2.

The body is accepted, the transition happens, but the comment does not appear in the ticket.
{
  "update": {
    "comment": [
      {
        "add": {
          "body": "This is a comment"
        }
      }
    ]
  },
  "transition": {
    "id": "31"
  }
{color:#000000}}

I am unable to add an 'Internal Comment'.
$url = "https://XXX.atlassian.net/rest/api/2/issue/{issuekey}/comment"
$headers = @{ "Authorization" = "Basic $encodedCreds" }
$Body = @

Invoke-RestMethod -Method Post -Uri $url -Headers $headers -Body (ConvertTo-Json $body).ToString() -ContentType "application/json"

Any update on this?

To Add some clarity on this issue it seems the Jira API works for this whereas the Jira service desk api does not. I need to use the Jira Service desk API to make the comment internal

GET

"https://jiraurl.com/rest/api/2/issue/{issueIdOrKey}/transitions"  works and returns transition ids

"https://jiraurl.com/rest/servicedeskapi/request/{issueIdOrKey}/transition" returns empty values

POST

"https://jiraurl.com/rest/api/2/issue/{issueIdOrKey}/transitions"  -works but cannot make comments internal  "public": "false", is ignored

"https://jiraurl.com/rest/servicedeskapi/request/{issueIdOrKey}/transition" returns 400 it just a simple example json body of a relevant transition id