Android’s Gboard always suggests replies in chat apps that fit the context of what my contacts write.
If my previous message had been related, I would assume it predicted what my contact would say in response and make a suggestion based on that. But even if the contact changes the topic, the suggestions are appropriate.
I don’t expect that the apps all share the conversation with Gboard. So how are the predictions made.
It seems unlikely that it would take screenshots and base predictions on that. But otherwise I don’t know how it is possible.
Gboard wouldn’t need to take screenshots. It can see what you’re typing as you’re typing it. As far as what your contacts are saying, if they’re using Gboard, it’s the same for them. And even if Google doesn’t admit it, we all know they’re correlating every single data point about people they can get, which includes who talks to who. I wouldn’t be surprised if they know you’re talking to a particular person and tailors your suggestions to fit the conversation. This is an even stronger possibility if you’re using one of Google’s messaging apps.