During downtime or game start, GM calls for “round of rumors”. Each player provides a rumor heard about the world (big or small, dramatic or mundane). GM secretly determines which are true. The rumor being heard is canon - player details how/from whom they heard it. True rumors show evidence if followed. False rumors have no substance. GM may also provide a rumor.
Lets players suggest what’s in their narrative sandbox while GM remains arbiter of truth.