Last updated: 2026-10-30
What is Claude Opus?
Anthropic's strong-reasoning Claude tier, described for long-running agentic coding and knowledge work. Opus 5.5 lists at $4 input / $20 output per million tokens and defaults to medium effort; Fable 5.1 ($10 / $50) sits above it for the most demanding reasoning. Usually overkill for routine agent loops.
See also
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