spacing and inset are universal attributes — every one of the 45 block runes that carries universals accepts both. Neither has a page that says what it does.
Found while checking whether /runes/surfaces was a sound link target for SPEC-128 D1's axis accordion. It is, for most axes, but not all.
Tracking started Sep 10 — check back for trends.
An author who sees spacing in editor completion, or in a rune's attribute list, can find out what it does.
spacing never appears in site/content/runes/surfaces.md. inset appears once, in passing, with no definition. Neither has a section anywhere.
site/content/runes/design/spacing.md is not it — that documents the {% spacing %} design rune, which renders a spacing scale for a design system. Different thing, similar name, which is likely why the gap survived: a search for "spacing" finds a page and stops.
grep -c '`spacing`' site/content/runes/surfaces.md # → 0 grep -c '`inset`' site/content/runes/surfaces.md # → 1, in passing
/runes/surfaces is organised by editorial theme — Chrome, Reading, Fills, Cover, Composition — rather than by the axis list. That is the right shape for a page an author reads front to back, and it is why the page is good. But it means an axis that belongs to no theme has no home, and nothing checks that every axis has one.
motion was noticed and given its own page. spacing and inset were not.
spacing is documented as a universal attribute, with its accepted valuesinset is documented as a universal attribute, with its accepted values/runes/surfaces, whether defined there or linked{% spacing %} design rune and the spacing universal attribute are distinguishable from their pages — the name collision is the reason this went unnoticedSmall, and worth doing before WORK-548 rather than after: D1's accordion links each axis to its documentation, so an axis with no page is a link with nowhere to go. Fixing it first means the accordion's link map is complete on the day it ships.
The axis→page map that WORK-548 needs is also the artifact that would have caught this. Consider asserting every axis in AXIS_ATTRIBUTES has an entry — then a future axis cannot be added without a documentation home, which is the failure that happened here.
/runes/surfaces the accordion's link target, which is what surfaced thispackages/runes/src/universal-attributes.ts — AXIS_ATTRIBUTES, the list every axis should be checkable againstCompleted: 2026-09-10
Branch: claude/content-author-docs-org-vps1un
site/content/runes/surfaces.md — new ## Spacing and inset section documenting both axes: what each controls (rhythm around vs padding within), the shared flush | tight | default | loose | breathe scale, that default emits nothing, and that the engine declares no closed value set so a theme can add its own steps. Both attributes added to the page's overview table.
site/content/runes/design/spacing.md — a note distinguishing the {% spacing %} design rune from the spacing attribute, with a link across. surfaces.md carries the reciprocal note. The name collision is the likeliest reason this gap survived: searching for "spacing" finds a page and stops.
--spacing-flush|tight|loose| breathe, and the same four for inset) plus the facet contracts in packages/transform/src/facets/box.ts, which say each is suppressed at default.## Spacing and inset — rhythm around and padding within, whose real slug keeps the em-dash — exactly the BUG-005 trap. Verified in the built HTML: id="spacing-and-inset".