Anthropic has officially announced its latest AI model dubbed Claude Sonnet 4.5. As per the company, it will be positioned as a coding performance and reliability and can make more than just prototypes, claiming it can autonomously build “production-ready” applications — a step up from its predecessors.
The Claude Sonnet 4.5 is now available through the Claude API and chatbot, with the pricing remaining unchanged from Claude Sonnet 4 at $3 per million input tokens and $15 per million output tokens. With this model, the company aims to compete with OpenAI’s GPT 5, which made headlines recently for surpassing Claude models in several coding benchmarks.
Despite the competition, Anthropic claims its new release is the best in the business. The model reportedly performed well in SWE-Bench Verified and other evaluations. However, according to Anthropic researcher David Hershey, benchmarks only capture a portion of its capabilities. He stated that in early enterprise trials, Claude Sonnet 4.5 coded autonomously for up to 30 hours, managing not only application development but also database setup, domain purchases, and even a security compliance audit.
The company also claims that the Claude Sonnet 4.5 is its most aligned model to date, with improved resistance to prompt injection attacks and decreased tendencies towards sycophancy or misleading responses.
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The Claude Agent SDK, which enables developers to create their own AI-powered agents using the same infrastructure as Claude Code, was announced along with the Claude Sonnet 4.5. Anthropic is also giving a sneak peek at “Imagine with Claude,” a research tool available to Max subscribers that allows for real-time software creation without the need for prewritten code.
Previously, the company unveiled the Claude Opus 4.1 in an attempt to boost competition in the AI industry.