feat(helpers): add standard schema support

[HAYDEN-OAI]

Summary

• add standardResponseFormat(), standardTextFormat(), standardFunction(), and standardResponsesFunction() under openai/helpers/standard-schema
• support any validator that implements Standard Schema validation plus either Standard JSON Schema conversion or a caller-supplied JSON Schema
• reuse the existing strict-schema transform so generated schemas stay compatible with Structured Outputs
• add the new helper entrypoint to JSR exports and generalize one shared strict-schema error from “Zod field” to “Schema field”

Motivation

Fixes #1945.

The SDK currently has Zod-specific helpers, while #1021 and the open Valibot-specific PR #1923 show the pressure to add another helper family for each schema library. Standard Schema provides a vendor-neutral validation interface, and Standard JSON Schema provides a vendor-neutral JSON Schema conversion interface, so the SDK can support Zod, Valibot, ArkType, and future libraries without adding runtime dependencies or per-library adapters.

Behavior

The helpers use schema["~standard"].jsonSchema.input({ target: "draft-07" }) for the model-facing schema, then pass that schema through toStrictJsonSchema(). Callers whose validator only implements Standard Schema validation can supply a schema override instead.

Parsed response content and tool arguments flow through schema["~standard"].validate(), preserving the schema’s inferred output type for parsed content and callback arguments.

Validation is intentionally synchronous. The SDK’s existing $parseRaw hooks are synchronous, so Promise-returning Standard Schema validators fail with an actionable error instead of introducing hidden async behavior into parse helpers.

Compatibility

This is additive and introduces no new runtime or peer dependencies. Existing Zod helpers are unchanged. The only existing behavior change is clearer shared-transform error wording for non-Zod schemas.

Validation

• pnpm exec jest tests/helpers/standard-schema.test.ts tests/helpers/zod.test.ts tests/lib/transform.test.ts --runInBand
• pnpm exec tsc --noEmit
• pnpm exec prettier --check src/helpers/standard-schema.ts src/lib/transform.ts tests/helpers/standard-schema.test.ts tests/helpers/zod.test.ts tests/lib/transform.test.ts jsr.json
• git diff --check
• pnpm run lint

[openai-sdks]

OkTest Summary

❌ Failed for Node SDK PR #1997.

View OkTest run #29368665427

_{SDK merge (8851f021feb8) · head (86fdd75d102d) · base (1cdc0196b434) · OkTest (cb7f0514ccd2)}

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: c4080eb882

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".