API version 2026-10-21 removes temperature, top_p and top_k

Anthropic released API version 2026-10-21 and new major SDK versions that send it by default. Under this version, temperature, top_p and top_k return a 400 error for every model, and the SDKs move from the MIT License to Apache 2.0.

Who is affected:

Any app that upgrades to the new SDK majors (Python 2.0.0, TypeScript 1.0.0 and others).

Action needed:

Remove sampling parameters before upgrading the SDK, or pin the older API version.