So, our PO does not add any description for the stories. He just a title like 'Develop x module' and expect us to guess what is. What should we do?

Fire him.

@spongessuck I wish I could, I'm just a developer not his manager

Quit, then.

Write you don't know what to do and play games or smth

Maybe politely ask him to change the issue type to Spike and explain your PO that after he adds more details, then you can transition it to a task or something. In that way he will feel that he is useful, progress is happening and nobody will get hurt.

I would ask him to add some description. If for whatever reason he doesn’t want to or he can’t, offer to add a description yourself and have him validate it. Chances are you’ll be far off from what he had in mind and it’ll force him to do the work he should’ve done in the first place

@black-kite Smart. Forcing him to sign off on instructions and hold him accountable. I like it