The response time
The AI never replies instantly, and that's deliberate: a reply that goes out within a second would give away a robot. In practice:
after a fan's message, the AI waits at least 30 seconds before sending its reply. This also gives the fan time to finish writing if they send several messages in a row;
most of the time, expect one to three minutes between the fan's message and the reply;
when the reply spans several messages (bubbles), they go out one after another, a few seconds apart, like a real person typing.
This delay can't be set: the AI handles it on its own, depending on the conversation with the fan.
The conditions for the AI to reply
The AI replies to a message if, at the time of the message, the model's AI and the conversation's automation are enabled, you're within the model's activity schedule (or in 24/7 Mode), the platform account is Connected and your credit balance isn't empty. To check them in order, follow "The AI is not replying: the checklist".
If one of these conditions isn't met, the message isn't lost: as soon as the situation clears (the time slot starts again, the balance is topped up, automation is re-enabled), the AI picks up the waiting conversations and replies.
Does the AI reply to everything?
The AI replies to the fan's latest message while taking the whole history into account. If the fan sent a media file, it "looks" at it (a description is generated automatically) and can react to it. However, it never opens a conversation on its own: it replies to fans, and it follows up according to your follow-up rules, including fans who never answered the welcome message (see "Set up automatic nudges (follow-ups)").