spec: `Field.scale` accepts meaningless declarations (`2.5`, `-1`) — now that scale is enforced, malformed declarations should be refused at authoring time

[os-zhuang]

Follow-up to #7501 (which remains open until its own PR lands; nothing here closes it).

What

packages/spec/src/data/field.zod.ts declares the field-level number constraint as:

scale: z.number().optional().describe('Decimal places'),

z.number() admits scale: 2.5 and scale: -1, neither of which has a defined meaning as a decimal-places count. The same looseness exists on precision (Total digits).

Why it matters now

#7501 made scale enforced at write time (rejection with max_scale). The runtime branch deliberately guards on Number.isInteger(def.scale) && def.scale >= 0 and leaves a malformed declaration unenforced — inventing floor/round semantics in a consumer would be the PD #12 guessing the ruling rejected. That is the correct runtime posture, but it means a typo'd declaration (scale: 2.5) silently gets no enforcement at all: exactly the declared-but-inert shape that hides AI-authored metadata errors.

The house shape is to refuse this at the producer: z.number().int().min(0) (and the analogous tightening for precision), so a meaningless declaration fails loudly at authoring/publish time instead of degrading to silence.

Notes for whoever takes it

• The runtime guard is pinned in packages/objectql/src/validation/record-validator.test.ts ("a malformed declaration (non-integer or negative scale) stays unenforced") — that pin should flip to authoring-time refusal semantics when the schema tightens, not be deleted.
• Tightening an authorable key changes the authorable surface: gen:schema artifacts and a fixture sweep across the schema's consumers are part of the change, and any stored metadata carrying a malformed value needs the ADR-0087 conversion-layer treatment rather than a hard break.
• CurrencyConfigSchema has its own precision with an alias table (field.zod.ts — scale → precision there) — a different surface; do not conflate the two (the A number field's declared scale is never enforced — values with more decimals are accepted and stored verbatim (min/max on the same field are enforced) #7501 thread documents the trap).

Generated by Claude Code

[hotlong]

Blocked-by: #7501

Triage: lands in packages/spec/src/data/field.zod.ts (plus the runtime pin flip in packages/objectql) → domain:spec, type Bug. A declaration the schema admits but whose declared meaning ("Decimal places") it cannot carry (2.5, -1) degrades to silent non-enforcement now that #7501 enforces scale — refusing it at the producer is the declared=enforced restoration (ADR-0078 shape, house pattern z.number().int().min(0); same tightening for precision). pm:blocked because the runtime pin this card must FLIP ("a malformed declaration stays unenforced" in record-validator.test.ts) lands with #7501's own PR — this is sequencing on the merged ref, not an open design question; unblocks when #7501 closes.

Dispatch notes (binding): pinned claude-fable-5 (changes the accept/reject face of the authorable surface — mandatory clause, no downward discretion); gen:schema artifacts + a fixture sweep across the schema's consumers are in scope; stored metadata carrying a malformed value takes the ADR-0087 conversion-layer treatment, not a hard break; ⚠️ CurrencyConfigSchema's own precision and its alias table (scale → precision) are a different surface — do not conflate (trap documented in the #7501 thread). Veto window open. 本评论来自分诊座位 Routine。

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