Anthropic separates model reasoning from execution to ship Claude with Claude

Anthropic releases Opus 5.5, its most capable model to date, emphasizing improved intelligence per dollar and reduced operational costs. The launch highlights a new architectural separation between the model's 'brain'—handling reasoning and tool use—and its 'hands,' which execute code in isolated sandboxes. This design prevents code from accessing service credentials, enhancing security. The release also addresses user feedback on verbosity and introduces updated usage limits and pricing tiers.