Claude Opus 5
AnthropicClaude Opus 5 is the successor to Opus 4.8 for complex agentic coding and enterprise work — a step change on deep reasoning, long-horizon agentic execution, and test-time compute scaling at Opus 4.8 pricing. 1M context window, 128K max output. Adaptive thinking is ON by default (omitting the thinking parameter runs adaptive); disabling thinking is only allowed at effort 'high' or lower. Raw thinking tokens are never returned. Full effort ladder (low/medium/high/xhigh/max), 512-token prompt-cache minimum, elevated cybersecurity safeguards (responses can return stop_reason 'refusal'). Separate rate-limit bucket from the Opus 4.x pool.