Anthropic Removes Three Sampling Controls From Claude API Requests

Anthropic’s 2026-10-21 Claude API version removes three sampling parameters from the Messages API, changing how developers can configure requests to the company’s AI models. It is the first formal API version released since 2023.

The removed parameters are temperature, top_p and top_k. Requests also return a 400 error if they include documents in an assistant turn or citations in a user turn.

The update replaces some deprecated fields in the Admin and Enterprise Analytics APIs. New major versions of Anthropic’s SDK and ant CLI use 2026-10-21 by default and include migration guides for developers adapting their integrations.

The earlier API version, 2023-06-01, has not been deprecated. Anthropic plans to publish API versions more often, giving developers a chance to handle incompatible changes before new models require them.