Claude Sonnet 4.5

Claude Sonnet 4.5

Claude Sonnet 4.5 is a state-of-the-art AI coding model designed for building complex agents and using computers effectively. It excels in reasoning, math, and long-duration autonomous coding tasks, making it ideal for developers, researchers, and professionals in finance, law, medicine, and STEM fields.

Claude Sonnet 4.5 is artificial intelligence software teams evaluate for software & gaming. Use this page to review pricing, integration signals, and the best alternatives before you commit.

Paid API Enterprise 75/100
#127 in Developer Tools (127 tools)
Added 0 year ago
17925 directory views this week

Quick Overview

Best for: Software & Gaming

What it does

Artificial Intelligence software for decision-makers comparing workflow fit and alternatives.

Best fit

Software & Gaming

Pricing snapshot

Paid from $3 per million tokens for standard usage, $15 per million tokens for higher volume or extended features

Next step

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Claude Sonnet 4.5

Claude Sonnet 4.5 is the most powerful and aligned coding model released by Anthropic, designed to handle complex, multi-step tasks with sustained focus for over 30 hours. It leads benchmarks in software coding abilities and real-world computer tasks, showing substantial improvements in reasoning, math, and domain-specific knowledge. The model supports advanced agentic capabilities, including tool use, code execution, and file creation, integrated into various products such as Claude Code, Claude apps, and the Claude for Chrome extension. It is available via the Claude API and offers a drop-in replacement for previous versions with improved performance at the same pricing.

The best coding model in the world

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Key Features

Advanced Coding Performance

State-of-the-art performance on SWE-bench Verified and other coding benchmarks, excelling in multi-step reasoning and code comprehension.

Long-Duration Autonomous Coding

Maintains focus and coherence for over 30 hours on complex coding and architectural tasks.

Tool Use and Agentic Capabilities

Supports parallel tool execution, code execution, file creation, and advanced agent memory and permission management.

Improved Alignment and Safety

Reduces misaligned behaviors such as deception and sycophancy, with robust defenses against prompt injection attacks and CBRN-related risks.

Claude Agent SDK

Provides developers with the infrastructure to build custom AI agents using the same foundation as Claude Code.

Integration with Developer Tools

Includes a native VS Code extension and refreshed terminal interface for enhanced developer experience.

Context Editing and Memory Tools

Enables agents to run longer and handle greater complexity through advanced context management features.

Cross-Domain Expertise

Demonstrates strong domain-specific knowledge and reasoning in finance, law, medicine, cybersecurity, and design.

Pricing

Standard API Usage

$3 per million tokens for standard usage, $15 per million tokens for higher volume or extended features
  • Access to Claude Sonnet 4.5 model
  • Code execution and file creation in Claude apps
  • Use of Claude Agent SDK

Use Cases

Software Development

Supports debugging, architecture design, codebase pattern learning, and production-ready code generation.

Autonomous Agent Building

Enables creation of complex AI agents with memory management, permission systems, and coordinated subagents.

Cybersecurity

Generates creative attack scenarios for red teaming and improves vulnerability detection and risk reduction.

Legal Analysis

Assists in analyzing litigation records, synthesizing legal opinions, and conducting detailed summary judgment analysis.

Financial Analysis

Delivers investment-grade insights for risk assessment, structured products, and portfolio screening with reduced human review.

Design and Prototyping

Enhances design workflows in tools like Figma and Canva by enabling easier prompting, iteration, and functional prototype creation.

Integrations

VS Code Extension

Native extension for Visual Studio Code enabling seamless coding with Claude Sonnet 4.5.

Claude for Chrome

Browser extension that allows Claude to interact with web pages, fill spreadsheets, and complete tasks directly in the browser.

Claude API

Programmatic access to Claude Sonnet 4.5 for integration into custom applications and workflows.

Benefits

Significant improvements in multi-step reasoning and long-context task handling.
Robust safety and alignment features reducing harmful or misleading outputs.
Seamless integration with existing developer tools and workflows.
Enables faster development cycles and higher code quality.
Supports a wide range of professional domains with specialized knowledge.
Provides developers with powerful SDK to build custom AI agents.
Improves efficiency and accuracy in cybersecurity and legal tasks.
Offers a drop-in upgrade with no price increase from previous versions.

Limitations

No free tier is available, which may limit access for some users.
Classifier filters may sometimes flag normal content as potentially dangerous, causing false positives.
High compute configurations may have inference issues as noted in recent reports.
Detailed technical and safety evaluations are complex and require review of the system card for full understanding.

Frequently Asked Questions

What improvements does Claude Sonnet 4.5 have over previous versions?
Claude Sonnet 4.5 offers significant gains in coding performance, reasoning, math, long-duration task handling, and alignment, with improved safety features and tool use capabilities.
How can I access Claude Sonnet 4.5?
You can access Claude Sonnet 4.5 via the Claude API using the model identifier 'claude-sonnet-4-5', or through Claude apps and developer tools like the VS Code extension.
Is there a free tier available for Claude Sonnet 4.5?
No free tier is mentioned; pricing starts at $3 per million tokens.
What is the Claude Agent SDK?
The Claude Agent SDK is a developer toolkit that provides the infrastructure to build custom AI agents using the same technology that powers Claude Code.
What safety measures are in place for Claude Sonnet 4.5?
Claude Sonnet 4.5 includes advanced safety classifiers to detect and block dangerous inputs and outputs, reduces misaligned behaviors, and is released under AI Safety Level 3 protections.

Getting Started

  1. 1 Step 1: Access Claude Sonnet 4.5 via the Claude API using the model identifier 'claude-sonnet-4-5'.
  2. 2 Step 2: Explore the Claude Agent SDK to build custom AI agents tailored to your needs.
  3. 3 Step 3: Utilize Claude Code, the native VS Code extension, or Claude apps to integrate coding and file creation capabilities into your workflow.

Support

Documentation

Comprehensive technical details and usage guides are available at https://docs.claude.com/en/docs/about-claude/models/overview.

Developer Posts

Engineering and research blog posts provide insights into building agents and cybersecurity applications at https://www.anthropic.com/engineering.

Contact

General inquiries can be directed via https://www.anthropic.com/contact.

API

Available: Yes
Documentation:

API documentation is available at https://docs.claude.com/en/docs/about-claude/models/overview.

Rate Limits:

Pricing is $3 per million tokens for standard usage and $15 per million tokens for higher volume or extended features; specific rate limits are not detailed.

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