CriticalDeprecation
Anthropic Deprecating Manual Thinking in Claude Opus 4.6 — Migrate to Effort Parameter
Action Required
Developers using manual thinking or the 1M token context window in Claude Opus 4.6 will experience service disruption after April 30, 2026, requiring immediate migration to a supported model.
AI Impact Summary
Anthropic is deprecating manual thinking and prefilling assistant messages in Claude Opus 4.6, transitioning to the new 'effort' parameter for controlling thinking depth. The deprecated `budget_tokens` parameter is being removed, and the 1M token context window is being sunset on April 30, 2026, requiring migration to Claude Sonnet 4.6 or Claude Opus 4.6. This change impacts developers relying on manual control of model depth and context window size, necessitating code updates and model selection.
Anthropic Deprecating Manual Thinking in Claude Opus 4.6 — Migrate to Effort Parameter
Affected Systems
Claude Opus 4.6
- Date
- Date not specified
- Change type
- deprecation
- Severity
- critical