News

AWS First Hyperscaler to Offer Anthropic's Claude Sonnet 4.5 Frontier Model

• By David Ramel
• 09/30/2025

Amazon Web Services (AWS) has become the first cloud hyperscaler to offer Anthropic's newest large language model, Claude Sonnet 4.5, making it available yesterday in Amazon Bedrock. This follows AWS's multibillion-dollar investment in Anthropic, which secured the company an early and exclusive position to deliver the AI provider's frontier models directly through its managed AI service.

Claude Sonnet 4.5 on AWS
Claude Sonnet 4.5 is Anthropic's most advanced model to date, designed for complex agentic workflows, coding, and reasoning tasks. According to AWS, the model introduces improvements in tool handling, memory management, and context processing, enabling it to maintain consistent performance across long-horizon tasks such as autonomous software development projects. Benchmarks show it surpassing earlier Claude releases and competitive models in areas like software engineering (SWE-bench Verified) and computer use (OSWorld), as well as domain reasoning in finance, research, and cybersecurity.

"Claude Sonnet 4.5 demonstrates advancements in agent capabilities, with enhanced performance in tool handling, memory management, and context processing," said a Sept. 29 AWS blog post." The model shows marked improvements in code generation and analysis, from identifying optimal improvements to exercising stronger judgment in refactoring decisions. It particularly excels at autonomous long-horizon coding tasks, where it can effectively plan and execute complex software projects spanning hours or days while maintaining consistent performance and reliability throughout the development cycle."

Anthropic was just as enthusiastic about the new frontier model in its own announcement: "Claude Sonnet 4.5 is the best coding model in the world. It's the strongest model for building complex agents. It's the best model at using computers. And it shows substantial gains in reasoning and math."

Integration with Amazon Bedrock
Through Bedrock, developers gain access to Claude Sonnet 4.5 via a unified API that integrates with Amazon Bedrock AgentCore. This pairing provides infrastructure for building production-ready AI agents with enterprise-grade security, long-running support, and observability features. Bedrock users can deploy Claude Sonnet 4.5 to scenarios ranging from autonomous code refactoring to financial risk analysis and proactive cybersecurity defense.

First Cloud Provider Advantage
AWS's deep partnership with Anthropic positioned it ahead of rival hyperscalers like Microsoft Azure and Google Cloud in offering Claude Sonnet 4.5. While Anthropic has made the model available through its own API, AWS is the first major cloud provider to operationalize it as a fully managed service, ensuring enterprise customers can immediately integrate the model without infrastructure overhead. This reflects the strategic edge AWS sought when it announced its investment and partnership with Anthropic in 2023.

Availability
Claude Sonnet 4.5 is available today in Amazon Bedrock across supported regions. Developers can begin experimenting with the model through the Bedrock documentation and APIs, with support for cross-Region inference profiles to optimize performance.