Sampling parameters deprecated on Claude Opus 4.7 and later

What changed

Impact summary

Anthropic documents the following behavior on the affected models: Omit parameters; non-default values return HTTP 400.

Beforetemperature, top_p and top_k accepted as request controls

After / replacementOmit parameters; non-default values return HTTP 400

Affected models and systems

Claude Opus 4.7 and laterclaude-mythos-preview

Migration action

Recommended next step: Remove the deprecated controls listed under Before from requests to the affected models. Follow the After behavior and add a request-contract test that rejects accidental non-default values.

Source and interpretation

API platform & regional scope

Anthropic Claude API · Direct developer platform; eligibility and regional restrictions are account-specific.

Not AWS Bedrock or Vertex AI.

Bounded manual catalog. Original event checks retained from 2026-09-01; not reverified in this expansion.

Unconfirmed regions are not assumed to be global. Automatic monitoring is OFF. Source checks

Official evidence locators

Existing normalized record: evt_anthropic_sampling_params. Locate listed affected model(s) in the lifecycle/release table; original manual check retained.

Original source date and qualifier retained; exact shutdown time is not inferred.

Affected endpoints: Not separately specified; check model / capability scope

Action / deadline: Review required · No stated deadline

This record is classified as official announcement. The facts above were normalized from the provider's public developer documentation. API Change Watch does not treat an unreviewed page diff as a verified announcement.

Read the official source ↗