University of Kwazulu-Natal

Everything To Know About Claude Sonnet 4 5 The World S Best Coding

Bonisiwe Shabane
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everything to know about claude sonnet 4 5 the world s best coding

Anthropic just released Claude Sonnet 4.5, and the benchmark numbers are honestly absurd. According to Anthropic, the model scored 77.2% on SWE-bench Verified (70.6 on SWEBench official leaderboard)—a test that throws real GitHub issues at AI models to see if they can actually fix code like a... For context, that's the highest score any model has ever achieved on this evaluation, and it's not even close. But here's what makes Sonnet 4.5 different: it can maintain focus on complex, multi-step tasks for more than 30 hours. Not 30 minutes. Not 3 hours.

Thirty. Hours. Try it yourself through the Claude API using the model string 'claude-sonnet-4-5'. You can also read the Claude 4.5 System Prompt here. We'll break down more about that below. Feel like there is a groundbreaking AI announcement every other week?

I get it. The fatigue is real. It’s hard to distinguish the hype from the tools that will actually change how we work. But if you only pay attention to one release this season, make it this one. Anthropic just released Claude Sonnet 4.5 (as of late September 2025). If you look at the raw numbers, they are absurdly good.

It’s crushing benchmarks left and right. However, the benchmarks aren’t the real story here. The real story is stamina. Imagine hiring a brilliant intern who forgets everything you said after 30 minutes. That’s been the reality of most AI models until now. Sonnet 4.5 changes the game.

It can maintain focus on complex, multi-step projects for over 30 hours. Anthropic released Claude Sonnet 4.5 on September 28, 2025, positioning it as “the best coding model in the world.” This update is a dramatic leap for coding capabilities, agent autonomy, and computer use that... Claude Sonnet 4.5 excels in coding, managing long-running agent tasks, and handling computer use. On SWE-bench Verified - the recognized standard for evaluating coding ability - Sonnet 4.5 scores 77.2% by default, reaching 82% with parallel test-time compute. This performance sets a new benchmark that puts competitors on notice. The model remains focused for over 30 hours, even during complex, multi-step projects.

Developers report improvements in longer-horizon tasks, with substantial gains in planning performance and evaluation scores. On the OSWorld benchmark, Sonnet 4.5 scores 61.4%, a significant boost from 42.2% with Sonnet 4 just months prior. Claude Sonnet 4.5 achieved 77.2% on SWE-bench Verified—the highest ever. See real developer feedback, pricing, and why it's the 'world's best coding model.' On September 29, 2025, Anthropic released Claude Sonnet 4.5 and immediately claimed the title of "the world's best coding model." According to official benchmarks, it scored 77.2% on SWE-bench Verified—the highest score any model... But does that translate to real-world developer productivity?

After analyzing hands-on testing, developer feedback, and verified performance data, here's everything you need to know. All data in this article is sourced from Anthropic's official releases, InfoQ technical analysis, developer testimonials, and verified benchmark leaderboards (November 2025). Unlike previous models that lose context or start hallucinating after a few hours, Claude Sonnet 4.5 can maintain focus on complex tasks for more than 30 hours straight without degradation. Unite.AI is committed to rigorous editorial standards. We may receive compensation when you click on links to products we review. Please view our affiliate disclosure.

If you’ve ever spent hours fixing a messy spreadsheet, debugging stubborn code, or keeping track of too many project details, you know how frustrating it can be. That’s where Claude Sonnet 4.5 comes in. It’s the latest AI from Anthropic, and it isn’t just another chatbot. It’s a powerhouse built for complex reasoning, coding, and managing large workflows to accomplish tasks efficiently. In this Claude Sonnet 4.5 review, I’ll discuss the pros and cons, what it is, who it’s best for, and its key features. Then, I’ll show you how I used it from start to finish to do research, collect data, create a slideshow, and write supporting automation code.

I’ll finish the article by comparing it with my top three alternatives (OpenAI GPT-5, DeepSeek-V3.2-Exp, and Google Gemini 3.0 Pro). By the end, you’ll know if Sonnet 4.5 is right for you! Claude Sonnet 4.5 is the best coding model in the world. It's the strongest model for building complex agents. It’s the best model at using computers. And it shows substantial gains in reasoning and math.

Code is everywhere. It runs every application, spreadsheet, and software tool you use. Being able to use those tools and reason through hard problems is how modern work gets done. Claude Sonnet 4.5 makes this possible. We're releasing it along with a set of major upgrades to our products. In Claude Code, we've added checkpoints—one of our most requested features—that save your progress and allow you to roll back instantly to a previous state.

We've refreshed the terminal interface and shipped a native VS Code extension. We've added a new context editing feature and memory tool to the Claude API that lets agents run even longer and handle even greater complexity. In the Claude apps, we've brought code execution and file creation (spreadsheets, slides, and documents) directly into the conversation. And we've made the Claude for Chrome extension available to Max users who joined the waitlist last month. We're also giving developers the building blocks we use ourselves to make Claude Code. We're calling this the Claude Agent SDK.

The infrastructure that powers our frontier products—and allows them to reach their full potential—is now yours to build with. This is the most aligned frontier model we’ve ever released, showing large improvements across several areas of alignment compared to previous Claude models. Anthropic just released Claude Sonnet 4.5, and they’re calling it “the best coding model in the world.” The new AI model beats both GPT-5 and Google’s Gemini 2.5 Pro on key programming benchmarks. Most impressive of all, this AI can code autonomously for more than 30 hours straight. The announcement came on September 29, 2025, and it’s already shaking up the AI development world. Companies like Cursor, GitHub Copilot, and Canva are already seeing major improvements in their products.

Claude Sonnet 4.5 scored 77.2% on SWE-bench Verified, the gold standard for measuring real-world coding abilities. This puts it ahead of GPT-5 at 72.8% and Gemini 2.5 Pro at 67.2%. When using advanced parallel computing, the score jumps to an incredible 82%. SWE-bench Verified tests how well AI models can solve actual GitHub issues. These aren’t simple coding problems. They’re complex, real-world software bugs that human developers face every day.

“Sonnet 4.5 achieves 77.2% on SWE-bench Verified. It is state-of-the-art,” an Anthropic spokesperson confirmed. Claude Sonnet 4.5, introduced by Anthropic on September 29, 2025, marks a major breakthrough in artificial intelligence for coding, reasoning, and computer use. Positioned as the best coding model in the world, it offers developers, researchers, and enterprises unmatched performance in building complex AI agents, executing software tasks, and solving challenging problems in domains like finance, law,... The SWE-bench Verified benchmark results show that Claude Sonnet 4.5 leads in software engineering performance with an accuracy of 82.0 percent when using parallel test-time compute, and 77.2 percent without it. This outperforms its predecessor Sonnet 4, which scored 80.2 percent with parallel compute and 72.7 percent otherwise.

Opus 4.1 also delivered strong results at 79.4 percent and 74.5 percent. By comparison, GPT-5 Codex and GPT-5 achieved 74.5 percent and 72.8 percent respectively, while Gemini 2.5 Pro trailed with 67.2 percent. These results highlight Sonnet 4.5’s position as the most capable coding model currently available. Claude Sonnet 4.5 is designed for modern workflows where code powers every application and system. It delivers substantial improvements in reasoning, math, and multi-step problem-solving compared to its predecessors. Key highlights include:

Superior coding performance: Sonnet 4.5 leads the SWE-bench Verified benchmark for real-world software coding. Unmatched computer use capabilities: Achieves 61.4 percent on OSWorld, outperforming earlier AI models in completing real-world computer tasks. Discover Claude Sonnet 4.5, the most capable coding model with state-of-the-art performance on SWE-bench Verified, now powering Claude Code 2.0's autonomous development capabilities. Claude Sonnet 4.5 represents a quantum leap in AI coding capabilities. It's not just an incremental improvement—it's the best coding model in the world, the strongest model for building complex agents, and the best model at using computers. Combined with Claude Code 2.0's autonomous features, it's transforming how developers work.

Claude Sonnet 4.5 achieves 77.2% on SWE-bench Verified, the gold standard evaluation for real-world software coding abilities. This isn't just about passing tests—it's about maintaining focus for more than 30 hours on complex, multi-step tasks. Real development teams are seeing transformative results: "We're seeing state-of-the-art coding performance from Claude Sonnet 4.5", with significant improvements on longer horizon tasks. It reinforces why many developers using Cursor choose Claude for solving their most complex problems. — Cursor Team

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Anthropic Just Released Claude Sonnet 4.5, And The Benchmark Numbers

Anthropic just released Claude Sonnet 4.5, and the benchmark numbers are honestly absurd. According to Anthropic, the model scored 77.2% on SWE-bench Verified (70.6 on SWEBench official leaderboard)—a test that throws real GitHub issues at AI models to see if they can actually fix code like a... For context, that's the highest score any model has ever achieved on this evaluation, and it's not even...

Thirty. Hours. Try It Yourself Through The Claude API Using

Thirty. Hours. Try it yourself through the Claude API using the model string 'claude-sonnet-4-5'. You can also read the Claude 4.5 System Prompt here. We'll break down more about that below. Feel like there is a groundbreaking AI announcement every other week?

I Get It. The Fatigue Is Real. It’s Hard To

I get it. The fatigue is real. It’s hard to distinguish the hype from the tools that will actually change how we work. But if you only pay attention to one release this season, make it this one. Anthropic just released Claude Sonnet 4.5 (as of late September 2025). If you look at the raw numbers, they are absurdly good.

It’s Crushing Benchmarks Left And Right. However, The Benchmarks Aren’t

It’s crushing benchmarks left and right. However, the benchmarks aren’t the real story here. The real story is stamina. Imagine hiring a brilliant intern who forgets everything you said after 30 minutes. That’s been the reality of most AI models until now. Sonnet 4.5 changes the game.

It Can Maintain Focus On Complex, Multi-step Projects For Over

It can maintain focus on complex, multi-step projects for over 30 hours. Anthropic released Claude Sonnet 4.5 on September 28, 2025, positioning it as “the best coding model in the world.” This update is a dramatic leap for coding capabilities, agent autonomy, and computer use that... Claude Sonnet 4.5 excels in coding, managing long-running agent tasks, and handling computer use. On SWE-bench Ver...