Anthropic removes non-default sampling controls starting with Claude Opus 4.7

Lifecycleactive

Severityhigh

ConsequenceAnthropic documents this as model behavior on its API; partner-platform behavior should be checked separately.

Componentstemperature, top_p and top_k on Claude Opus 4.7 and later

AudienceDevelopers setting non-default sampling parameters on Claude Opus 4.7 or later models, including Claude Mythos Preview.

RegionClaude API behavior for affected models

Stable event IDksr-anthropic-sampling-controls-opus-4-7

Change typebreaking_api_change

BeforeParameters accepted

AfterNon-default values rejected

ActionRemove temperature, top_p and top_k overrides from affected requests and use prompting to guide behavior.

Replacement or migration pathOmit temperature, top_p and top_k on affected models and use explicit prompting to guide response behavior.

Date roleEffective date

Date2026-04-16

Statusactive

StatusNot tested

LimitationsSource evidence reviewed; no paid vendor call or production reproduction was run.

Checked2026-09-04

Official sourceshttps://www.anthropic.com/news/claude-opus-4-7 · https://platform.claude.com/docs/en/release-notes/overview · https://platform.claude.com/docs/en/about-claude/models/migration-guide · https://platform.claude.com/docs/en/about-claude/model-deprecations

Correction historyNo corrections recorded.