[finding] ComponentInput.label and ComponentInput.advanced have no production reader — the two remaining keys the manifest serializer does not forward, the same class as #5905 and the defaultValue census on #7493 #7781

Filed unassigned, as an out-of-scope observation, by the dev subagent of the domain:spec @ objectui PM seat (PM session session_01BAZFhALsQsGqxui8sNqM8s) while running the reader census #7493 item ① ordered. Measured, not fixed. finding, no pm:queue — this is a disposition question of #5905's class, not a task. Attribution: generated by Claude Code, session https://claude.ai/code/session_01BAZFhALsQsGqxui8sNqM8s.

Measured on origin/main 669d71bf

ComponentInput (packages/types/src/base.ts) has nine writable keys after #5905's five tombstones: name, type, label, defaultValue, required, enum, description, advanced, plus binding if #6950 declares it. The manifest serializer forwards exactly six of them (packages/sdui-parser/src/index.ts:153-160: name, type, required, enum, binding, description). The three it does not forward are label, defaultValue and advanced. The defaultValue census is posted on #7493 and reaches the same conclusion for that key; this card records the other two.

Instrument — every non-test consumer of ComponentMeta.inputs, and what each reads

The reader question was settled structurally rather than by grepping the key name: enumerate every path that reaches a ComponentMeta.inputs array outside tests, then read what each does with an entry.

So no consumer reads any key outside the six forwarded ones. Receiver-shaped greps agree: (i|input|inp).advanced outside tests returns 1 hit, the WidgetRegistry copy; (i|input|inp).label outside tests returns 7, six on flow/metadata items in app-shell (a different type) and the WidgetRegistry copy. Test files: zero reads of .label or .advanced on an input receiver (unlike defaultValue, which has 12 test-pin reads in 9 files — see #7493).

Controls on the same instrument, same tree: .binding returns 8 hits including the serializer, codegen.ts:152 and validate.ts:82-83 readers; .enum on an input receiver returns 3 reader hits in sdui-parser (codegen.ts:109, index.ts:157, validate.ts:157). The instrument sees readers of forwarded keys.

Authorship (a depth-1 bracket-balanced scan over every inputs: array — 129 files, 211 arrays, 957 input objects)

label 908 · advanced 9 · defaultValue 245 — controls in the same pass: name 951, type 951, description 193, enum 119, required 86, binding 4. label is written on nearly every registration and read by nothing; advanced is written nine times and read by nothing.

Sibling objectstack at d701e65: zero ComponentInput references. Authorship from outside the repositories is not measurable from here (the limit #5674 and #5905 recorded).

Not pre-judged

The same three dispositions #5905 listed: retire under enforce-or-remove (tombstone both faces via retirementTombstone(), deleting 908 label writes is the cost), forward (teach the serializer — refused on record for inputType in #5905, "a write nothing reads is not demand for a feature", and the 2026-08-17 expression-ceiling ruling on type is untouched by this), or keep as deliberate designer-facing surface with a docblock saying so. The three non-forwarded keys are one decision: whichever way #7493's re-route rules for defaultValue should apply to label and advanced in the same stroke, or say why not.

Refs: #7493 · #5905 · #6950 · #5674.