# `mix openui.gen.spec`
[🔗](https://github.com/ideia4it/openui/blob/v0.1.1/lib/mix/tasks/openui.gen.spec.ex#L1)

Writes the LibrarySpec of a library module, the `library.json` other
clients (a React app, a mobile app) build their library from.

    mix openui.gen.spec MyApp.Library --out assets/library.json

With `--check` nothing is written. The task fails when the new spec would
break programs stored with the old one (a prop moved or removed, a new
required prop without a default), when the file is out of date, or when it
is not a valid LibrarySpec. Run it in CI so the file never drifts from the
module.

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*Consult [api-reference.md](api-reference.md) for complete listing*