What
When Claude Code checks an artifact (a generated file or page shown to the user) for runtime diagnostics and finds none, it shows an explanatory message. That message now also covers the case where the artifact's page runtime simply doesn't report diagnostics at all, which happens with older artifact pages, in addition to the existing cases of a missing viewer or an owner-only artifact.
Why
This gives a clearer, more accurate explanation when no diagnostics show up for an older artifact page, instead of leaving it looking like an unexplained gap.