Anthropic has released its latest frontier AI model, Claude Sonnet 4.5, built for high-performance coding and building complex agents. Anthropic claims it is “the best coding model in the world” and “the best model at using computers,” with substantial gains in reasoning and math. Claude Sonnet 4.5 is distinctive in that it can build “production-ready” applications and is not limited to prototypes, Anthropic says, describing it as a major gain over previous models. The new model also excels in research as well as enterprise basics like cybersecurity and finance, per Anthropic.

“The model generates higher-quality code, is better at identifying code improvements and can follow instructions more reliably,” CNBC reports Anthropic co-founder and Chief Science Officer Jared Kaplan shared in an interview.

“People are just noticing with this model, because it’s just smarter and more of a colleague, that it’s kind of fun to work with it when encountering problems and fixing them,” Kaplan added during his discussion with CNBC.

Additionally, a new context editing feature and memory tool has been added to the Claude API to allow agents to “run even longer and handle even greater complexity” and larger context windows, Anthropic explained in a news post.

Claude apps have gained code execution and file creation (spreadsheets, slides, and documents) capabilities. And a Claude for Chrome extension has been made available to Claude Max subscribers who joined the waitlist last month.

Claude Sonnet 4.5 is available to all users “via the Claude API and in the Claude chatbot,” TechCrunch writes, noting “the pricing for developers is the same as Claude Sonnet 4: $3.

Developers and enterprises have come to lean on the Claude models for software engineering tasks though OpenAI’s GPT-5, released in August, has gained some ground. “Apple and Meta reportedly use Claude AI models internally, and Anthropic has made a significant business selling API access to AI coding applications such as Cursor, Windsurf, and Replit,” TechCrunch reports.

Coming on the heels of Claude Opus 4.1, launched in August, and Claude Sonnet 4 in May, Claude 4.5 Sonnet is “the latest example of the breakneck pace of innovation within the AI industry,” CNBC notes.

Related:
Available Today: Claude Sonnet 4.5 in Microsoft Copilot Studio, Microsoft, 9/29/25
Anthropic Claude Sonnet 4.5 Is in Public Preview for Copilot Coding Agent, GitHub, 9/30/25
Introducing Claude Sonnet 4.5 in Amazon Bedrock: Anthropic’s Most Intelligent Model, Amazon, 9/25