A design system binds like a rule but reached a session only through the
session-start block: complete for a session that asks, silent for one
writing a component. The write-path hint now carries a design arm.
A trigger, not a search: a project has one design system, so the question
is answered by the file being UI (.vue, .css, .tsx, ...) in a project that
has one. No vectors, no score, no slot from the ranked menu.
An index, not the prose: resolved guidance runs to ~8,000 chars (the house
style alone), near the hook's whole additionalContext cap. The line names
each inherited layer's section headings and inlines a layer short enough to
be a line - in practice the leaf's departure.
The other arms do not move. A design-only write returns on its own rather
than joining the prior-art guard, so the standing-rule arm still runs only
where it ran before. Once per session per system, on the hook's existing
token-keyed channel (exclude_derive, design:<id>) - no plugin change.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01821k5B3Ysecp9fNYs92Kuy
