Opus 4.7 Adaptive Thinking Is a Breaking API Change — budget_tokens Returns 400 Error, Thinking Hidden by Default
r/ClaudeAI·medium signal
Opus 4.7's new 'adaptive thinking' feature silently broke existing API integrations. Setting thinking budget_tokens now returns a 400 error — a breaking change with no migration path. Thinking content is omitted from responses by default without raising errors, causing silent quality degradation. Third-party SDKs haven't updated their supportsAdaptiveThinking() checks. On r/ClaudeAI, 'Adaptive thinking is a joke' hit 254↑ (43 comments). Users report disabling adaptive thinking and increasing effort level restores baseline performance.