What
An artifact is a piece of content, such as a small app or page, that Claude Code builds and shows. Its startup can now ask for a lighter "lean" boot. If the reply to that request is incomplete, Claude Code notes it and starts the artifact in full instead.
A startup already done to check sharing can also now be reused for other kinds of artifact in some cases.
Why
In practice, a lighter startup never leaves an artifact half-loaded, because an incomplete one falls back to a full start.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
Which features ask for the lighter boot is not known.