Schema/draft model layer for settings editors. The wire's settings.describe carries each namespace's serialized schemastery schema (schema.toJSON() ref envelope); rehydrateSchema turns it back into a live validator with new Schema(json) — the same schema object that validates a section on the host validates drafts in the browser, so client-side validation never drifts from the seam's. Editors render their own controls (the Models page hand-writes its card around the fields it probes here); this package owns no React and no rendering.

Contract

The unit of editing is a draft user section: a plain object edited immutably (setPath materializes intermediates, deletePath is the per-field reset — dropping the key falls the resolved value back to the composition base and schema defaults). A field's presence in the draft marks it overridden (hasPath) — presence semantics, not value comparison, exactly mirroring the settings seam's layering. nodeAtPath resolves the schema node addressed by a configurable-provider directory settingsPath (object properties by name, dict entries through inner), so an editor can probe which fields a provider's profile carries (and their meta.role) before deciding what to render; an unresolvable path returns undefined so the caller degrades loudly instead of rendering a wrong subtree. validateDraft(schema, draft) runs the rehydrated validator and returns its failure message, letting pages reject an invalid draft before writing.

Model Experience

None, as this package backs browser configuration editors; nothing here reaches a model request.

KV Cache effect

None; this package neither assembles nor sends a provider request.

Known Limitations and Deferred Work

Rehydration executes the served envelope — rehydrateSchema reconstructs a live schemastery validator, and schemastery revives serialized callbacks through new Function, so the schema envelope is executable content rather than inert data. That is acceptable only because the envelope comes from the same host that serves the page; a browser schema protocol should carry a description the client cannot execute, which is deferred with the settings seam's wire-boundary work.
Validation is draft-level, not per-field — validateDraft reports schemastery's first failure message (which names the $.path); per-field error mapping is deferred until a consumer needs it.
No generic renderer — a schema-driven form component was built and then replaced by the hand-written Models editor (Agent Note); if a future page needs to edit arbitrary sections, it starts from these helpers, not from a resurrected generic renderer, unless the note's trade-off changes.