Validate Query/Mutation output shapes against component prop types

[ChuckJonas]

Is your feature request related to a problem? Please describe.

There's no way to test that data from Query()/Mutation() calls will actually work with the components they're bound to without rendering the full UI. If a query returns the wrong shape, you only find out at render time.

Describe the solution you'd like

A way to pass mock query results into the parser or a test utility and get back validation errors — basically a dry run of the data binding without rendering.

const errors = validateView(code, library, {
  portfolio_summary: { total: 5 },
  holdings: [{ sector: "Tech", value: 50000 }],
});

// -> [{ path: "summary.sectors", component: "PieChart", prop: "data",
//        message: "property 'sectors' not found in query output" }]

Feed it the OpenUI Lang, the library, and the query outputs — get back a list of binding mismatches. Missing keys, type mismatches (scalar where array expected), etc.

Describe alternatives you've considered

Rendering with onError to catch failures, but that requires the full renderer and only reports the first error.

Additional context

This would be useful for CI checks, save-time validation, and any workflow where views are persisted and re-rendered without an LLM in the loop to self-correct.

[Aditya-thesys]

Thanks for filing this.

Rather than a separate validateView utility, I think we can cover both your use case and render-time detection with a single mechanism: let Query() accept default values (already supported as the 3rd arg, Query(tool, args, defaults, refresh)), and let the parser/renderer optionally inject defaults per query from the outside.

That does two things at once:

1. Bindings are validated against the defaults shape, and mismatches surface via Renderer's onError or Parser's meta.errors.
2. Fallback when the LLM forgets. If the model doesn't emit a defaults arg, we can still inject them through the parser (@openuidev/lang-core) or Renderer at render time, so both validation and placeholders keep working.

For your CI/persistence flow, you'd just inject defaults (same shape as your mock results) through the parser and read any mismatches from ParseResult.meta.errors.

WDYT?