If you ask Inkeep about history, by default it implies Pub/Sub message storage is 24-72 hours, with no explicit mention of longer storage.
Chat however is correct, which makes it clear this is a documentation issue:
I have been using an agent to plan out a feature for a chat app demo I wam working no, and it too came to the wrong conclusion:
We need to be far more explicit in Pub/Sub docs to address this shortfall. This directly impacts our goals of ensuring developers succeed when evaluating Ably.
In addition, we need to ensure our dashboards offer a way to request longer message storage durations.