Claude Sonnet 5 ranks fifth in the Artificial Analysis Intelligence Index with 53 points and even beats the pricier Opus 4.8 on some agent-based tasks. But the model chews through about 40 percent more tokens per task than its predecessor, nearly doubling real costs despite identical list prices. Anthropic's hidden price hikes are becoming a pattern.

Claude Sonnet 5 is the most agentic Sonnet model yet, rivaling Opus 4.8 in performance at lower prices, Anthropic said.

Claude Sonnet 5 brings near-Opus 4.8 agentic performance at a mid-tier price, from $2/$10 per million tokens until August 31. Here's what is new.