Claude Sonnet 4.5: Anthropic’s Most Powerful AI for Coding
▼ Summary
– Anthropic launched Claude Sonnet 4.5, a frontier AI model that offers state-of-the-art coding performance and can build production-ready applications.
– The model is available via the Claude API and chatbot at the same pricing as its predecessor: $3 per million input tokens and $15 per million output tokens.
– Claude Sonnet 4.5 demonstrated capabilities in early trials by autonomously coding for up to 30 hours, performing tasks like building applications, setting up databases, and conducting security audits.
– Anthropic claims it is their most aligned frontier model yet, with reduced sycophancy, deception, and improved resistance to prompt injection attacks.
– The company is also releasing the Claude Agent SDK for developers and a temporary research preview called “Imagine with Claude” for real-time software generation.
Anthropic has introduced Claude Sonnet 4.5, positioning it as the company’s most advanced AI model for software development. This new frontier model reportedly delivers top-tier results on coding benchmarks and can create production-ready applications rather than just experimental prototypes. Available through the Claude API and chatbot, the model maintains the same pricing as its predecessor, $3 per million input tokens and $15 per million output tokens.
Over the past year, Anthropic’s models have become a preferred choice for developers and large organizations, thanks to their strong software engineering capabilities. Major firms like Apple and Meta are said to use Claude models internally, and Anthropic provides API access to popular coding platforms including Cursor, Windsurf, and Replit. However, OpenAI’s recent GPT-5 release has intensified the competition, outperforming earlier Claude versions on several coding benchmarks.
Anthropic asserts that Claude Sonnet 4.5 leads the industry on key coding evaluations such as SWE-Bench Verified. Still, Anthropic researcher David Hershey notes that benchmark scores alone don’t fully reflect the model’s capabilities. During early enterprise testing, he observed Claude Sonnet 4.5 coding autonomously for as long as thirty hours. In that time, the system built a complete application, configured database services, purchased domain names, and even conducted a SOC 2 security audit.
Industry leaders have voiced strong support for the new model. Cursor CEO Micheal Truell described Claude Sonnet 4.5 as representing the cutting edge in coding performance, especially for extended tasks. Windsurf CEO Jeff Wang echoed this, calling it a “new generation of coding models.”
Anthropic also highlights improvements in AI safety and alignment. The company states that Claude Sonnet 4.5 shows reduced sycophancy and deception compared to earlier versions and has better defenses against prompt injection attacks.
Alongside the model release, Anthropic is launching the Claude Agent SDK. This toolkit provides developers with the same infrastructure that powers Claude Code, enabling them to build custom AI agents. Additionally, a temporary research preview called “Imagine with Claude” is available for Max subscribers. This feature demonstrates the AI generating software in real time, responding to user requests without relying on prewritten code or predefined functions.
The AI industry continues to move at a breakneck pace, with leading companies releasing flagship models every few months. Claude Sonnet 4.5 arrives less than two months after Anthropic’s previous model, Claude Opus 4.1. Such rapid iteration makes it challenging for any single organization to maintain a durable competitive advantage in the field.
(Source: TechCrunch)
