Anthropic launches Claude Opus 5: near-Fable performance at half the price

[AINews] Claude Opus 5: Fable-level performance at Opus price (half Fable)

Anthropic dropped Claude Opus 5 on a Friday. Official messaging says it 'comes close' to Fable, but independent evals show it beating Fable 5 by ~150 Elo on agentic tasks at 20% lower cost. Epoch's ECI gives it 159 vs Fable 5's 161, though SWE-ECI ties at 161. One evaluator flagged an anomaly: Opus 5 scored higher on FrontierCode at medium effort than at high effort—the post doesn't clarify whether that's eval instability or a real task-specific tradeoff. Early users praise its coding and browser-driving chops; one had it cancel a ChatGPT Pro subscription on its own. Arena's real-world scores aren't out yet. Nous Portal already offers access with a 20% discount across all models.

Why it matters: Anthropic dropped Opus 5 on a Friday with independent evals showing ~150 Elo over Fable 5 on agent tasks at 20% lower cost. Epoch ECI 159 vs Fable 161, SWE-ECI tied. This is the Opus refresh Claude subscribers have been waiting for, with a strong price-performance signal. Held...