Interface: ResponseFormat<TData>

Defined in: types.ts:359

Structured output format specification.

Constrains the model's output to match a specific JSON structure. Useful for extracting structured data, form filling, or ensuring consistent response formats.

See

• https://platform.openai.com/docs/guides/structured-outputs
• https://sdk.vercel.ai/docs/ai-sdk-core/structured-outputs

Type Parameters

TData

TData = any

TypeScript type of the expected data structure (for type safety)

Properties

__data?

optional __data: TData;

optional __data: TData;

Defined in: types.ts:437

Internal

Type-only property to carry the inferred data type.

This is never set at runtime - it only exists for TypeScript type inference. Allows the SDK to know what type to expect when parsing the response.

json_schema?

optional json_schema: object;

optional json_schema: object;

Defined in: types.ts:376

JSON schema specification (required when type is "json_schema").

Defines the exact structure the model's output must conform to. OpenAI's structured outputs will guarantee the output matches this schema.

description?

optional description: string;

optional description: string;

Optional description of what the schema represents.

Helps document the purpose of this structured output.

Example

"User profile information including name, email, and preferences"

"User profile information including name, email, and preferences"

name

name: string;

name: string;

Unique name for the schema.

Used to identify the schema in logs and debugging. Should be descriptive (e.g., "user_profile", "search_results").

schema

schema: Record<string, any>;

schema: Record<string, any>;

JSON Schema definition for the expected output structure.

Must be a valid JSON Schema (draft 2020-12 or compatible). The model's output will be validated against this schema.

See

https://json-schema.org/

Example

{
     *   type: "object",
     *   properties: {
     *     name: { type: "string" },
     *     age: { type: "number" },
     *     email: { type: "string", format: "email" }
     *   },
     *   required: ["name", "email"],
     *   additionalProperties: false
     * }

{
     *   type: "object",
     *   properties: {
     *     name: { type: "string" },
     *     age: { type: "number" },
     *     email: { type: "string", format: "email" }
     *   },
     *   required: ["name", "email"],
     *   additionalProperties: false
     * }

strict?

optional strict: boolean;

optional strict: boolean;

Whether to enforce strict schema validation.

When true (recommended), the model guarantees output will match the schema exactly. When false, the model will "best effort" match the schema.

Default: true (for providers that support it)

See

https://platform.openai.com/docs/guides/structured-outputs#strict-mode

type

type: "json_object" | "json_schema";

type: "json_object" | "json_schema";

Defined in: types.ts:368

Type of structured output.

• "json_object": Forces the model to output valid JSON (any structure)
• "json_schema": Validates output against a provided JSON Schema (strict structure)

See

https://platform.openai.com/docs/api-reference/chat/create#chat-create-response_format