---
title: "Introducing Claude Sonnet 4.5"
description: "The release introduces Claude Sonnet 4.5 as a model aimed at complex coding, agentic work, computer use, reasoning, and math, with claimed gains in alignment. It reports state-of-the-art SWE-bench Verified performance and a 61.4% OSWorld score, up from Sonnet 4’s 42.2%, while noting more than 30 hours of observed focus on complex multi-step tasks. Alongside the model, the company released Claude Agent SDK, added Claude Code checkpoints, a refreshed terminal interface, native VS Code extension, context editing, and a memory tool, and brought code execution and file creation to paid Claude apps. Sonnet 4.5 is available through the Claude API as claude-sonnet-4-5 at $3/$15 per million tokens, the same pricing as Sonnet 4. It is released under AI Safety Level 3 protections, with reported reductions in concerning behaviors and improved defenses against prompt injection, while the temporary Imagine with Claude preview is available to Max subscribers for five days."
---

# Introducing Claude Sonnet 4.5

[Anthropic](https://yomu.fyi/company/anthropic) · Jul 22, 2026

**Type:** Announcement

## Summary

The release introduces Claude Sonnet 4.5 as a model aimed at complex coding, agentic work, computer use, reasoning, and math, with claimed gains in alignment. It reports state-of-the-art SWE-bench Verified performance and a 61.4% OSWorld score, up from Sonnet 4’s 42.2%, while noting more than 30 hours of observed focus on complex multi-step tasks. Alongside the model, the company released Claude Agent SDK, added Claude Code checkpoints, a refreshed terminal interface, native VS Code extension, context editing, and a memory tool, and brought code execution and file creation to paid Claude apps. Sonnet 4.5 is available through the Claude API as claude-sonnet-4-5 at $3/$15 per million tokens, the same pricing as Sonnet 4. It is released under AI Safety Level 3 protections, with reported reductions in concerning behaviors and improved defenses against prompt injection, while the temporary Imagine with Claude preview is available to Max subscribers for five days.

## Context

The release positions Claude Sonnet 4.5 for modern work involving code, software tools, difficult reasoning, and long-running agentic tasks. It also addresses safety concerns associated with agentic and computer-use capabilities, including prompt injection and other concerning model behaviors.

## Approach / What changed

The release combines a new model with product and developer-platform changes: Claude Code checkpoints, a refreshed terminal interface, a native VS Code extension, context editing, a memory tool, code execution and file creation in Claude apps, and the Claude Agent SDK based on the infrastructure powering Claude Code. It also applies AI Safety Level 3 protections and classifiers for potentially dangerous inputs and outputs.

## Takeaways

- Claude Sonnet 4.5 reports a 61.4% OSWorld score, compared with 42.2% for Sonnet 4 four months earlier, and more than 30 hours of observed focus on complex multi-step tasks.
- The Claude Agent SDK exposes the infrastructure used by Claude Code for building agents beyond coding, including solutions for memory, permission systems, and coordinating subagents.
- Claude Sonnet 4.5 keeps Sonnet 4 pricing at $3/$15 per million tokens and is released under AI Safety Level 3 protections with defenses against prompt injection and classifiers for CBRN-related content.

**Tags:** [AI Agents](https://yomu.fyi/topic/ai-agents), [Claude](https://yomu.fyi/topic/claude), [Computer Use](https://yomu.fyi/topic/computer-use), [Model Evaluation](https://yomu.fyi/topic/model-evaluation)

- Source: [Anthropic](https://www.anthropic.com/news/claude-sonnet-4-5)
- Source URL: https://www.anthropic.com/news/claude-sonnet-4-5
- Ingested by Yomu: 2026-09-09T11:37:09.062Z

[Read original post](https://www.anthropic.com/news/claude-sonnet-4-5)