We know how important xdebug in php is .. no post on that 🙂
when it is through the url, we will use the

XDEBUG_SESSION_START=somevariable

But, when you are using curl or some other client for using a post, cookie is a rescue

CURL_COOKIE = 'XDEBUG_SESSION=somevariable'

Just add the above as one of the curl options and you should be good.