How to Create a Custom GPT Using Claude Sonnet 4.5 - The Best Coding AI Model

Introducing Claude Sonnet 4.5: The Coding Revolution

Anthropic has unveiled Claude Sonnet 4.5, marking a groundbreaking advancement in AI coding capabilities. As the world's best coding model achieving an unprecedented 77.2% on SWE-bench Verified, Sonnet 4.5 transforms how we build, deploy, and scale AI applications. With the ability to code autonomously for over 30 hours, this model represents the future of AI-powered development.

🏆 Claude Sonnet 4.5 World-Leading Performance

Sonnet 4.5 dominates global AI benchmarks:

• 77.2% on SWE-bench Verified - #1 globally for real-world coding
• 61.4% on OSWorld - Leading computer use benchmark
• 30+ hours autonomous coding - Proven in enterprise deployments
• 0% error rate on code editing - Down from 9% with Sonnet 4
• 18% better planning performance - Verified by Devin AI
• 44% faster vulnerability patching - Security agent performance

💻 Why Sonnet 4.5 is the Best Coding Model

Anthropic's latest model excels across every dimension of software development:

Development Capabilities

• Writes production-ready code
• Tests its own implementations
• Handles complex architectures
• Manages database services
• Performs security audits

Real-World Achievements

• Builds complete applications
• Purchases domain names
• Conducts SOC 2 compliance
• Patches vulnerabilities proactively
• Handles 30+ hour projects

🧠 Extended Thinking: A Game-Changer

Claude Sonnet 4.5 introduces revolutionary extended thinking capabilities:

• Visible reasoning chains - Watch the AI think through problems step-by-step
• Fine-grained control - API users can adjust thinking duration
• 30+ hour focus - Maintains context on complex, multi-step tasks
• Superior problem-solving - Tackles challenges previous models couldn't handle

What Makes Claude Sonnet 4.5 Revolutionary

🤖 Best-in-Class Agent Building

Agent Excellence

• Superior instruction following
• Advanced tool selection
• Automatic error correction
• Complex workflow management
• Prompt injection defense

Enterprise Results

• 12% better end-to-end scores
• 25% accuracy improvement
• 44% faster processing
• Production-ready output
• Scale to millions of users

Perfect Use Cases for Claude Sonnet 4.5

⚡

Autonomous Coding Agent

Build apps that code themselves, handle databases, and deploy to production with minimal oversight.

🛡️

Security Operations

Deploy agents that autonomously patch vulnerabilities before exploitation, shifting from reactive to proactive defense.

💰

Financial Analysis

From entry-level analysis to advanced predictive modeling and intelligent risk management systems.

🖥️

Computer Use Automation

Leading OSWorld benchmark at 61.4%, automating complex computer tasks previously impossible for AI.

📊

Office Productivity

Excel at producing and editing slides, documents, spreadsheets with human-like understanding.

🔍

Research & Analysis

Search through external and internal data sources to synthesize comprehensive insights across complex landscapes.

Step-by-Step: Build Your Claude Sonnet 4.5 App

1 Sign Up for CalStudio

Create your account on CalStudio.com to access Claude Sonnet 4.5 - the world's most advanced coding AI model.

2 Create Your Application

Click the "Create App" button to start building with Claude Sonnet 4.5's revolutionary capabilities.

3 Select Claude from Menu

Choose the "Claude" option to access Anthropic's cutting-edge models, including the new Sonnet 4.5.

4 Configure Your Claude Sonnet 4.5 Bot

Set up your bot to leverage Sonnet 4.5's unique capabilities:

Bot Name: Choose a name that reflects your app's advanced capabilities
Avatar Image: Upload a professional image or logo
Model Selection: Select "Claude Sonnet 4.5 (Anthropic)" for the best performance
System Prompt: Design prompts that leverage extended thinking and coding abilities
Knowledge Base: Upload technical documentation, API references, or codebases
Extended Thinking: Enable for complex reasoning tasks

Claude Sonnet 4.5 configuration form showing model selection and settings

                    💡 Pro Tips for Sonnet 4.5
                    • Extended Thinking: Enable for complex problems requiring step-by-step analysis
• Coding Tasks: Leverage the 77.2% SWE-bench score for production-ready code
• Long Projects: Take advantage of 30+ hour focus for complex implementations
• Agent Building: Use superior instruction following for autonomous workflows
• Security: Built-in prompt injection defense for safer deployments

                

5 Launch Your Revolutionary AI

Click "Create App" to deploy your Claude Sonnet 4.5 application. Your AI will be ready to handle complex coding tasks, extended reasoning, and autonomous operations.

🧪 Testing Sonnet 4.5's Capabilities

• Coding Challenge: Ask it to build a complete application from scratch
• Extended Thinking: Give complex problems and watch the reasoning unfold
• Agent Tasks: Test autonomous workflows and tool usage
• Error Handling: Verify the 0% error rate on code editing
• Long Sessions: Test sustained performance over extended periods

6 Scale and Monetize

Deploy your Claude Sonnet 4.5 app with enterprise-grade capabilities. Share through custom domains like codinggenius.cals.app and monetize your AI innovation.

⚡ Sonnet 4.5 vs Competition

Why Claude Sonnet 4.5 dominates the AI landscape:

Performance Metrics

• 77.2% SWE-bench (vs GPT-5: ~65%)
• 61.4% OSWorld (vs others: ~45%)
• 0% code edit errors (industry-leading)
• 30+ hour autonomous operation

Business Impact

• 44% faster development cycles
• 25% higher accuracy
• 90% cost savings with caching
• Production-ready from day one

Exclusive Claude Sonnet 4.5 Features

🚀 Next-Generation Capabilities

Extended Thinking Mode

• Visible step-by-step reasoning
• API control over thinking time
• Complex problem decomposition
• Near-instant to extended analysis

Developer Tools

• Checkpoints for progress saving
• Native VS Code extension
• Context editing features
• Memory tools for long sessions

Pricing and Availability

💼 Enterprise-Ready Pricing

Claude Sonnet 4.5 offers exceptional value for its world-leading capabilities:

Pricing Structure

• $3 per million input tokens
• $15 per million output tokens
• 90% savings with prompt caching
• 50% savings with batch processing

Platform Availability

• CalStudio (immediate access)
• Claude Developer Platform
• Amazon Bedrock
• Google Cloud Vertex AI

Real-World Success with Sonnet 4.5

                    🏆 Enterprise Testimonials
                    Devin AI: "18% planning improvement and 12% better end-to-end scores - the biggest jump since Claude 3.6"
Security Teams: "44% faster vulnerability patching with 25% accuracy improvement"
Finance Sector: "Handles everything from entry-level to advanced predictive analysis autonomously"
Development Teams: "0% error rate on code editing - a game-changer for production deployments"

                

Start Building with the World's Best Coding AI

Claude Sonnet 4.5 isn't just an incremental improvement - it's a revolutionary leap in AI capabilities. As the world's best coding model with extended thinking, autonomous operation, and unmatched safety features, it empowers developers to build applications previously thought impossible.

🚀 Your Next Steps with Sonnet 4.5

Join the AI revolution today:

✅ Sign up for CalStudio - instant access
✅ Select Claude Sonnet 4.5 model
✅ Enable extended thinking for complex tasks
✅ Build autonomous coding agents
✅ Deploy production-ready applications
✅ Scale to millions with enterprise features

Whether you're building the next billion-dollar startup, revolutionizing enterprise workflows, or creating cutting-edge AI agents, Claude Sonnet 4.5 provides the foundation for unprecedented innovation. With 77.2% on SWE-bench, 30+ hour autonomous operation, and the most aligned safety features, your AI applications will lead the market.