What
Bundled skills are the skills that ship with Claude Code. The filter that decides which ones are available used to either keep them all or keep only those on a kill switch's survivor list. It now has a further case: when a certain condition holds, bundled skills are dropped unless they are on that survivor list or fail a check on their name. Claude Code can now also mark which bundled skills this applies to.
Why
In practice, some bundled skills may not be available in some sessions.
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 condition triggers this filter or what the name check tests.