Claude Opus 4.8: CI-First Benefit Score 6.3/10, CI-First Strong, Humics-Neutral. Anthropic's May 2026 Opus, now documented as Active (legacy) with retirement not sooner than 2027-05-28. Strong for its generation on contained work and the silent cyber fallback for Claude Opus 5.5, and 25 percent dearer than its successor on input and output with cache reads at 2.5 times the Opus 5.5 rate.