Claude Sonnet 4.5

Claude Sonnet 4.5 is positioned as a frontier workhorse for software engineering and autonomous agent workflows, with Anthropic framing it as the strongest model for building complex agents and for using computers, along with substantial gains in reasoning and math. The launch was accompanied by ecosystem upgrades designed to take advantage of those strengths, including checkpoints and a native VS Code extension for Claude Code, and a new context editing plus memory tool in the Claude API that lets agents run longer and handle greater complexity. Independent developer tooling reflected the same emphasis, with Augment Code making the model its default the same day it was announced, signaling that the model is well-suited as a backbone for IDE- and agent-driven development environments.

Beyond raw capability, Claude Sonnet 4.5 is delivered through a broader platform that includes code execution and file creation directly inside the Claude apps, plus an expanded Claude for Chrome extension for select Max users, giving developers multiple surfaces to integrate it into. Head-to-head reporting against GPT-5 has examined its coding, reasoning, math, tool use, cost, and ecosystem fit, helping enterprises decide where it slots into their stack. Successors in the same family have since shipped, with Sonnet 4.6 adding improved coding and developer tools, and a newer Sonnet 5 release highlighting a steeper price-to-performance angle, which shapes how teams may choose between the latest and most cost-effective options for production workloads.

Azureclaude-sonnet-4-5claude-sonnet

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Quick Info

Provider: Azure
Model key: claude-sonnet-4-5
Release date: Nov 18, 2025
Last updated: Nov 18, 2025
Knowledge cutoff: 2025-07-31
AI SDK package: @ai-sdk/anthropic
Input modalities
Output modalities
Capabilities

Cost

Input token cost: $3.00
Output token cost: $15.00

Limits

Output tokens: 64,000 tokens
Context window: 200,000 tokens

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Rates are shown per one million tokens. Combined means one million input plus one million output tokens.

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Latest news about Claude Sonnet 4.5

Azure

Coverage

Anthropic's new Claude Sonnet 5 delivers near-flagship AI performance at 60% lower cost, targeting enterprise adoption as the company races toward a landmark IPO at a nearly $1 trillion valuation.

Azure

Coverage

Claude Sonnet 4.6 brings improved coding performance, expanded developer tools, enhanced API capabilities, and updated safety evaluations.

Azure

CoverageBenchmark

A head-to-head comparison of Claude Sonnet 4.5 and GPT-5, covering coding, reasoning, math, tool use, cost, and ecosystem integrations , with insights on where each model is best suited for enterprise use.

Azure

CoverageRelease Notes

The most powerful AI software development platform with the industry-leading context engine.

Venice AI

CoverageBenchmark

CodeRabbit's benchmark evaluation compared Claude Sonnet 4.5 against Sonnet 4 and Opus 4.1 across 25 difficult real-world pull requests with known critical bugs. Sonnet 4.5 achieved 41.5% "Important" comments versus 35.3% for Sonnet 4, demonstrating measurable progress in catching bugs and surfacing critical issues inc The evaluation found Sonnet 4.5 approaches Opus 4.1's coverage and precision at a fraction of the price, making it a pragmatic sweet spot for code review at scale. However, the model showed more hedging and self-questioning behavior, sometimes sounding like "a thoughtful colleague rather than a decisive reviewer." This

Venice AI

CoverageBenchmark

Cirra AI's technical analysis confirms Claude Sonnet 4.5 was released September 29, 2025, with a 200,000-token context window and up to 64K output tokens. The model uses a hybrid reasoning architecture with an "extended thinking" mode for multi-step tasks, enabling more sophisticated agentic workflows. Anthropic positi New API-side tools shipped alongside Sonnet 4.5 include context editing, memory, checkpoints, and VS Code integration to support long-running agentic workflows. The model demonstrated autonomous operation spanning 30+ hours on complex tasks. These capabilities reflect Anthropic's focus on making Sonnet 4.5 suitable for