Anthropic Deprecates Fixed Extended Thinking, Forces Adaptive Thinking on Claude Models

Anthropic is deprecating the ability to disable adaptive thinking in Claude Code and Claude API. Effective now, manual extended thinking (thinking: {type: "enabled", budget_tokens: N}) is no longer supported on Claude Opus 4.7 — it returns a 400 error. For Opus 4.6 and Sonnet 4.6, manual configuration is still functional but deprecated and will be removed in a future model release.

The change means adaptive thinking (thinking: {type: "adaptive"} with effort parameter) becomes the default and only mode. Users who previously disabled adaptive thinking to maintain quality — citing noticeable degradation in Claude Code output — lose that toggle.

Key Details

• Opus 4.7: Manual extended thinking disabled entirely; use adaptive thinking with effort parameter.
• Opus 4.6 & Sonnet 4.6: Adaptive thinking recommended; manual mode deprecated, will be removed.
• API users: Cannot opt into fixed reasoning budget even if willing to pay for extra tokens.

Community Reaction

The /r/ClaudeAI thread (by u/CaffeineBrogrammer) questions the rationale: if adaptive thinking improves performance as Anthropic claims, why did quality drop in Claude Code disappear when disabling it? And why remove the option for paying API customers who want predictable reasoning depth? Skeptics see it as a cost-cutting measure disguised as improvement.

Who It's For

Developers using Claude Code, Claude API with extended thinking, or relying on consistent reasoning budgets for quality-sensitive tasks.