Anthropic's Claude Fable 5.1 promises better coding and research at up to 45 percent less
Anthropic has launched Claude Fable 5.1 and Mythos 5.1. The reporting indicates that Fable 5.1 doubles its predecessor's performance on the Terminal-Bench-Science benchmark, improves agentic coding efficiency by over 30 percent, and cuts costs by up to 45 percent for multi-tool autonomous agent runs.