You'll notice
Session resume can now match messages by a shared uuid prefix when the full uuid isn't available
What
When Claude Code looks up a specific message in a session's history (to resume or reattach to it), it now tries an exact match first, checking assistant and user message ids, sub-messages grouped under tool use, and collapsed read/search groups. If no exact match is found, it now falls back to matching messages that share the same uuid prefix (a fixed number of leading characters).
Why
This lets Claude Code reattach to the right point in a session even in cases where only a partial uuid is available, instead of failing to find a match at all.