What
When you send a message, Claude Code now gathers a set of facts about the model before the turn starts and passes them in with your request. A turn is one round of you sending something and Claude answering. This happens only for turns you start yourself, not for turns Claude Code starts on its own.
Messages that Claude Code adds at the start of a turn are also now marked by a new step before they are sent.
Why
This may change what the model is told about itself at the start of each of your turns.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
It is not clear what facts about the model are gathered, or what the new marking of start-of-turn messages does.