Retain full validation beside a compatible schema
Keep the full business validation contract when a host accepts only a reduced schema representation.
These examples and illustrative results are independently authored teaching materials, not measured model results.
Use case
A host accepts numeric shapes but not teaching price>=0/positive-integer qty. The wire projection provides types only; strict labels do not enforce removed business constraints.
Mechanism
Retain the canonical full contract/validator, derive verified supported projection and inventory omissions. Check full validation plus parsing/refusal/truncation before use. Descriptions and host labels replace no actual enforcement.
Bad example
Drop minimum, accept price=-5 and claim complete policy because strict.
Good example
Use supported wire types while retaining full teaching validation for nonnegative price/positive-integer qty. Map omissions to real checks and reject invalid/incomplete/refused/truncated output before quote creation. Schema compilation is not business validation.
Why the change matters
Compatibility governs transport while the full validator governs permissible data. Separate layers preserve policy through adaptation.
Observable expectation
Price=-5/qty2 may fit numeric wire types but fails full validation; price 0/qty1 satisfies these numeric rules. Inspect every omitted condition’s enforcement and incomplete-data rejection.
Passing establishes no source truth; no quote is created.
Limits
Host/SDK subsets change, and validators need tests. Frozen support lists are not current guarantees or authorization/truth evidence.