Anthropic releases Claude Sonnet 5, a more capable AI

Anthropic has launched Claude Sonnet 5, a new mid-tier artificial intelligence model designed to perform complex, autonomous tasks at a cost significantly lower than its most powerful systems. The model became available on Tuesday, June 30, 2026, across all of the company's user plans.

The company describes Sonnet 5 as its most capable and "agentic" Sonnet model yet, meaning it can formulate plans, use tools like web browsers and computer terminals, and operate autonomously for extended periods. This level of performance was previously associated with larger, more expensive models. Anthropic states the new model represents a substantial improvement over its predecessor, Sonnet 4.6, in areas including reasoning, coding, and knowledge work.

Official benchmarks released by Anthropic show Sonnet 5 closing much of the performance gap with the company's flagship Opus 4.8 model. On the SWEbench Pro coding test, Sonnet 5 scored 63.2 percent, up from Sonnet 4.6's 58.1 percent, though still behind Opus 4.8's 69.2 percent. In a test of real-world professional knowledge tasks, GDPvalAA v2, Sonnet 5 scored 1,618, a statistical tie with Opus 4.8's 1,616. The company also highlighted improved...