Although this isn’t documented yet, it is available on our API (version 5).
To Deny:
POST api.twitch.tv/kraken/chat/twitchbot/deny
{
"msg_id" : "foobar-foobar-foobar-foobar"
}
To allow a message:
POST api.twitch.tv/kraken/chat/twitchbot/approve
{
"msg_id" : "foobar-foobar-foobar-foobar"
}