Anthropic says its new AI model “maintained focus” for 30 hours on multistep tasks

On Monday, Anthropic released Claude Sonnet 4.5, a new AI language model the company calls its "most capable model to date," with improved coding and computer use capabilities. The company also revealed Claude Code 2.0, a command-line AI agent for developers, and the Claude Agent SDK, which is a tool developers can use to build their own AI coding agents.

Anthropic says it has witnessed Sonnet 4.5 working continuously on the same project "for more than 30 hours on complex, multi-step tasks," though the company did not provide specific details about the tasks. In the past, agentic models have been known to typically lose coherence over long periods of time as errors accumulate and context windows (a type of short-term memory for the model) fill up. In the past, Anthropic has mentioned that previous Claude 4.0 models have played Pokémon for over 24 hours or refactored ...