Anthropic's new Opus 5 model is priced at $5/MTok input and $25/MTok output, significantly lower than Fable 5's $10/$50 rates, and offers improved performance over Opus 4.8. The model leads the Artificial Analysis Intelligence Index at 61 points and shows strong gains in agentic coding, computer use, and long-horizon knowledge work. Anthropic also reduced the Claude Code system prompt by 80% and introduced an automated API fallback for dangerous requests, alongside a no-data-retention policy.