Anthropic Launches Claude Sonnet 4.5, Hailed as New AI Coding Leader

Anthropic has released Claude Sonnet 4.5, its most powerful AI model yet. The company announced the launch on Monday, September 29, 2025. It is immediately available to all users worldwide.

Anthropic states this new model sets a fresh benchmark for performance. It is specifically designed to outperform competitors in key areas like coding and complex reasoning.

Superior Performance Against Rivals

According to Anthropic, Claude Sonnet 4.5 is the best coding model available. It reportedly beats other leading models like OpenAI’s GPT-5 and Google’s Gemini 2.5 Pro. The model also shows major improvements in math and logical reasoning.

These gains make it exceptionally strong for building complex AI agents. It is also more capable at using computers to perform tasks. This represents a significant step forward in practical AI application.

New Features and Enhanced Safety

The launch introduced a suite of new tools. A new terminal interface and “checkpoints” for Claude Code were added. Checkpoints act like save points, letting developers roll back to earlier states.

The Claude apps now support direct code execution and file creation. Users can make spreadsheets and documents right in the chat. A Claude Agent SDK is also available for building custom agents.

Anthropic emphasized the model’s extensive safety training. They report a reduction in undesirable behaviors like sycophancy and deception. This makes the AI more reliable and trustworthy for all users.

Claude Sonnet 4.5 is available now and represents a major leap in AI capability. Anthropic strongly recommends that all users upgrade to this new model to experience its advanced features.

Info at your fingertips

What is Claude Sonnet 4.5’s main advantage?

Its primary advantage is superior performance in coding tasks. Anthropic claims it is the best coding model in the world, outperforming rivals like GPT-5.

Is Claude Sonnet 4.5 available now?

Yes, the model launched on September 29, 2025. It is available to all users globally starting from that date.

What are ‘checkpoints’ in Claude Code?

Checkpoints function like save points in your coding projects. They allow you to save your progress and revert to a previous state if needed.

Does it have new safety features?

Yes, it includes extensive safety training. This reduces issues like sycophancy and deceptive behavior for more reliable interactions.

Can it create files directly?

Yes, the updated apps allow for direct file creation. You can generate spreadsheets, slides, and documents within the conversation.