What
The /design command no longer has its "canvas" mode. That mode loaded design canvas files and let Claude start /design on its own. Now Claude can never start /design by itself; only you can run it.
Why
The design canvas path is gone from this command in the terminal, so /design runs only when you type it.
Names in the bundle/design
Documented inapi/manage-claude/cmek
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The writer flagged doubt
It is unclear whether the canvas mode moved somewhere else or was removed entirely.