Anthropic has introduced Claude Sonnet 5, the latest iteration of its medium-sized AI model, which is now the default for both free and pro users of Claude. This upgrade marks a significant step forward in agentic performance, with the model capable of making plans, using tools like browsers and terminals, and operating autonomously at a level previously reserved for larger and more expensive models.

Sonnet 5 sits between the smaller Haiku model and the larger Opus model in Anthropic’s lineup. The company describes it as the most agentic Sonnet model yet, with improved performance in key areas such as reasoning, tool use, coding, and knowledge work. These enhancements are expected to make the model more effective for enterprise applications that require complex, autonomous operations.

The performance of Sonnet 5 is now closer to that of the Opus model, but at a significantly lower cost. Anthropic has introduced introductory pricing for the model, offering $2 per million input tokens and $10 per million output tokens through August 31, 2026. After this period, the standard pricing will increase to $3 per million input tokens and $15 per million output tokens.

The improved capabilities and lower costs of Sonnet 5 may influence enterprise adoption, as businesses seek more efficient and cost-effective AI solutions. However, the shift to a more agentic model may also raise concerns about vendor lock-in, governance, and the potential for increased complexity in managing autonomous systems. Market reactions will depend on how well the model integrates with existing workflows and infrastructure.

As enterprises evaluate the benefits of Sonnet 5, they will need to consider the trade-offs between performance, cost, and control. The model’s enhanced agentic capabilities could streamline operations, but they may also require additional resources for oversight and integration. The broader AI industry will likely watch how this upgrade affects competition and innovation in the medium-sized model segment.