Unclear The reserved prefix itself is not identified.
What
Hooks are your own scripts that Claude Code runs at set moments. Each hook is registered with a pattern that decides when it fires. Claude Code now checks these patterns, and when one starts with a reserved prefix it shows a warning: "that name cannot be a noun, so this hook is never run". A single ! at the start of the pattern is ignored for this check, so ! followed by the reserved prefix triggers the same warning.
Why
Before this check, a hook named this way simply never ran, with nothing telling you why. If you write hooks, the warning now points you to the pattern that needs renaming.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The reserved prefix itself is not identified.