It runs inside Apple's own Messages app rather than a separate client, and covers iMessage, SMS and RCS — in Codex and ChatGPT Work too, so a work account is in reach.
An OpenAI add-on released last Thursday connects Apple's Messages app on the Mac to ChatGPT, letting the assistant read a user's texts, search them, write and send them, and delete them.
Once a user connects their inbox, ChatGPT loads what is there and works over it: surfacing an old detail lost somewhere far back in a thread, boiling a conversation down and fielding questions about what was said in it, and on request writing a reply or wiping messages out. In OpenAI's own marketing clip for the add-on, a user asks the chatbot to suggest what to send to people, drawing on texts that had arrived the day before.
On data, OpenAI's position comes to two claims: the add-on works on the user's own computer, and it builds no index covering all of a person's texts — no standing catalogue of a whole message history. What either claim covers in practice, the company has not explained.
OpenAI attaches its own warning to the moment a message leaves: switching standing, always-on permission on, it says, strips away the last opportunity a person has to look over a text before ChatGPT sends it out for them.