ElicitRequestedSchema was a TypeAlias for dict[str, Any]; it is now a
Pydantic model of the spec's restricted requested-schema subset, backed
by a new PrimitiveSchemaDefinition union (StringSchema, NumberSchema,
BooleanSchema, and the enum schemas). ServerSession.elicit_form (and the
deprecated elicit alias) and ClientPeer.elicit_form accept only this
model, so a nested-object property, an array-of-objects property, or an
anyOf union is unconstructible at the only place a server author
supplies a schema, rather than silently forwarded to the client.
The spec restricts form-mode requested schemas to flat objects with
primitive-typed properties only ("complex nested structures, arrays of
objects ... are intentionally not supported"). The high-level
Context.elicit / elicit_with_validation path is unchanged in behaviour:
it converts the rendered JSON Schema into the typed model, keeping its
existing per-field TypeError contract and producing value-identical wire
output.
Inbound is deliberately untouched. The wire field
ElicitRequestFormParams.requested_schema stays a plain dict[str, Any],
so older servers that emit anyOf for Optional form fields still reach
the client's elicitation callback. The typed-model-to-wire-dict
conversion lives in one place, ElicitRequestedSchema.to_wire(), which
both send sites call.
The schema family is extra="allow": keys schema.ts does not name (a
top-level title, pattern, exclusiveMinimum, json_schema_extra keys)
still round-trip, because the primitives-only restriction is carried by
the union members' required type literals, not by extra-key rejection.
Max Isbey