Update the gemini configuration to handle JSON schema

[hugoattal]

Currently, the @tanstack/ai-gemini adapter use the old responseSchema property which only handle a limited subset of JSON schema. https://github.com/TanStack/ai/blob/main/packages/typescript/ai-gemini/src/adapters/text.ts#L182

Gemini now allows a responseJsonSchema with a valid JSON schema, which allow a lot more flexibility: https://ai.google.dev/gemini-api/docs/structured-output?hl=fr&example=recipe

Could you please update it?

[hugoattal]

From gemini typescript file (genai.d.ts):

export declare interface GenerateContentConfig {
    responseMimeType?: string;
    /** The `Schema` object allows the definition of input and output data types.
     These types can be objects, but also primitives and arrays.
     Represents a select subset of an [OpenAPI 3.0 schema
     object](https://spec.openapis.org/oas/v3.0.3#schema).
     If set, a compatible response_mime_type must also be set.
     Compatible mimetypes: `application/json`: Schema for JSON response.

     If `response_schema` doesn't process your schema correctly, try using
     `response_json_schema` instead.
     */
    responseSchema?: SchemaUnion;
    /** Optional. Output schema of the generated response.
     This is an alternative to `response_schema` that accepts [JSON
     Schema](https://json-schema.org/). If set, `response_schema` must be
     omitted, but `response_mime_type` is required. While the full JSON Schema
     may be sent, not all features are supported. Specifically, only the
     following properties are supported: - `$id` - `$defs` - `$ref` - `$anchor`
     - `type` - `format` - `title` - `description` - `enum` (for strings and
     numbers) - `items` - `prefixItems` - `minItems` - `maxItems` - `minimum` -
     `maximum` - `anyOf` - `oneOf` (interpreted the same as `anyOf`) -
     `properties` - `additionalProperties` - `required` The non-standard
     `propertyOrdering` property may also be set. Cyclic references are
     unrolled to a limited degree and, as such, may only be used within
     non-required properties. (Nullable properties are not sufficient.) If
     `$ref` is set on a sub-schema, no other properties, except for than those
     starting as a `$`, may be set. */
    responseJsonSchema?: unknown;
}

[hugoattal]

Ok, it wasn't actually what I was looking for... I wanted to have JSON Schema validation for tools properties, but it seems Gemini does not support this for now 😕

[tombeckenham]

Hi, we are working on a PR to support output schemas natively. I hadn't added Gemini but I'll look at this. We are also working on a second PR to support the new Gemini interactions API.