Error adding File to Message, attachments[0].tools[0].type missing_required_parameter

Im trying to add a File to a message in a thread, but get this response

I have checked the playground and as far as I can tell my response is identical, if I add a file to a message.

{
  "error": {
    "message": "Missing required parameter: 'attachments[0].tools[0].type'.",
    "type": "invalid_request_error",
    "param": "attachments[0].tools[0].type",
    "code": "missing_required_parameter"
  }
}

POST is

https://api.openai.com/v1/threads/{threadId}/messages
{
   "role":"user",
   "content":[
      {
         "type":"text",
         "text":"Hello"
      }
   ],
   "attachments":[
      {
         "file_id":"file-5qRBphw6nYJOcbPElxZWbnO",
         "tools":[
            {
               "type":"file_search"
            }
         ]
      }
   ]
}