Claude Sonnet 4.5: A New Era in Coding, SWE-bench, and Developer Tools

September 29, 2025

3 min read

by Ufuk Ozen

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The latest Anthropic news is here: Claude Sonnet 4.5 has been announced! This new model is shaking up the coding world, setting a new record on the SWE-bench test. Learn all about Claude Code, the new VS Code extension, and what this means for other Claude models.

Claude Sonnet 4.5: Anthropic Raises the Bar for Coding and AI Agents

Breaking news from the world of artificial intelligence: Anthropic has just announced Claude Sonnet 4.5, and it's making waves. This isn't just an update; it's a revolution in coding, complex agent creation, and computer interaction. Keywords like claude 4.5 and anthropic news are spiking on Google Trends, proving the massive impact of this announcement.

The New King of Coding: `claude code` and `SWE-bench` Triumph

The most exciting news for developers is Sonnet 4.5's unparalleled coding capability. The model has achieved state-of-the-art performance on the rigorous SWE-bench Verified evaluation, establishing its leadership in the field. This means the model can maintain focus for over 30 hours on complex, multi-step tasks.

These superior abilities are further enhanced by the new Claude Code features:

VS Code Extension: The power of Claude is now directly inside your favorite code editor. This integration allows you to seamlessly incorporate Claude into your modern development workflows, including npm-based projects.
Checkpoints: You can now save your progress on large tasks and instantly revert to a previous state if you encounter a problem, providing a crucial safety net.

Beyond Code: Advanced Reasoning and Domain Knowledge

Claude Sonnet 4.5 doesn't just stand out from other claude models in coding. It has also claimed the top spot in computer interaction with an impressive 61.4% on the OSWorld benchmark. Experts in fields like finance, law, and medicine note that the model exhibits a significant superiority in domain knowledge and reasoning compared to previous generations.

Powerful API Innovations for Developers

Anthropic hasn't forgotten developers building AI agents for long-running tasks. Two new capabilities added to the Claude API eliminate the problem of hitting context window limits:

Context Editing: Automatically clears old or irrelevant context to increase efficiency.
Memory Tool: Stores information outside the context window, providing Claude with a persistent knowledge base.

"Imagine with Claude": A Glimpse into the Future

Anthropic is also offering a temporary research preview called "Imagine with Claude." In this experiment, Claude generates software on the fly, dynamically adapting to interactions with no pre-written code.

Availability and Pricing

One of the best parts of this anthropic news is that Claude Sonnet 4.5 is available everywhere, starting today. Developers can begin using the claude-sonnet-4-5 model via the Claude API at the same price point as claude sonnet 4 ($3/$15 per million tokens).

In conclusion, Anthropic's latest move signals a new dawn for AI-assisted software development and automation. claude 4.5 is undoubtedly a model that all developers and tech enthusiasts should be watching closely.