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Claude Code Complete Guide

Claude Code 2025 New Features Complete Guide

Latest Update (January 17, 2025)

Claude Code has reached GA (General Availability)! Claude Opus 4 and Claude Sonnet 4 have been released, delivering significant improvements in coding performance.

Key Points

  • :material-brain-2: Extended Thinking Mode

    Deeply analyzes complex problems over minutes to hours, providing high-quality solutions

  • Full IDE Integration

    Seamless development experience running natively in VS Code and JetBrains IDEs

  • Latest API Capabilities

    Accelerated performance with Claude Opus 4, File API, and prompt caching

  • GitHub Actions Integration

    Background task execution in CI/CD pipelines

📖 Overview

In 2025, Claude Code has evolved from a simple coding assistant into a comprehensive development platform. Revolutionary features including Claude Opus 4, IDE integration, and extended thinking mode dramatically improve development efficiency.

🎯 Latest Updates - January 2025

Claude Code GA (General Availability) Launch

In January 2025, Claude Code officially reached General Availability. Key changes:

  • Pricing Plans: Claude Code now available in both Pro and Max plans
  • Background Tasks: Task execution via GitHub Actions enabled
  • IDE Integration: Native integration with VS Code and JetBrains realized

Claude 4 Model Performance Improvements

Latest benchmark results:

ModelSWE-benchTerminal-benchFeatures
Claude Opus 472.5%43.2%World's best coding model
Claude Sonnet 472.7%-Combines fast response with high accuracy

New API Capabilities

  • Code Execution Tool: Direct code execution from API
  • MCP Connector: Remote server connection with OAuth 2.0 support
  • Files API: Efficient processing of large files
  • Prompt Caching: Cache retention up to 1 hour

Industry Partnerships

  • GitHub: Claude Sonnet 4 adopted for GitHub Copilot's new coding agent
  • Cursor: Praised as "cutting edge of coding"
  • Replit: Reports improved accuracy in complex multi-file changes

🧠 Extended Thinking Mode

Feature Overview

Extended thinking mode is a feature where Claude Code deeply thinks through complex problems over minutes to hours, providing better solutions.

# Enable extended thinking mode
claude --thinking-mode extended "complex architecture design problem"

# Set thinking time
claude --thinking-time 30m "large-scale refactoring plan"

# Background execution
claude --background --thinking-mode extended "system-wide optimization proposal"

Use Cases

1. Architecture Design

# Comprehensive system design analysis
claude --thinking-mode extended "
We are considering a microservices architecture design.
Please propose an optimal configuration meeting the following requirements:
- Process 10 million requests per month
- 99.9% availability requirement
- Geographic distribution support
- Balance security and performance
"

2. Performance Optimization

# Comprehensive performance analysis
claude --thinking-mode extended "
Analyze the current web application and
develop an optimization plan from the following perspectives:
- Database query optimization
- Frontend rendering performance
- API response time improvement
- Cache strategy review
"

3. Security Audit

# Detailed security analysis
claude --thinking-mode extended "
Conduct a comprehensive application security audit and
propose vulnerability analysis and countermeasures based on OWASP Top 10"

💻 IDE Integration Features

VS Code Extension

Installation and Setup

# Install Claude Code VS Code extension
code --install-extension anthropic.claude-code

# Create configuration file
cat > .vscode/settings.json << 'EOF'
{
  "claude.apiKey": "${ANTHROPIC_API_KEY}",
  "claude.model": "claude-opus-4",
  "claude.autoSuggest": true,
  "claude.inlineEdits": true,
  "claude.contextAware": true
}
EOF

Key Features

// Inline edit assistance
function calculateTotal(items: Item[]): number {
  // Launch Claude Code with Ctrl+Shift+C
  // "Optimize this function and improve type safety"

  return items.reduce((total, item) => {
    if (!item || typeof item.price !== 'number') {
      throw new Error('Invalid item data');
    }
    return total + (item.price * (item.quantity || 1));
  }, 0);
}

JetBrains Integration

IntelliJ IDEA Setup

# Plugin installation
# File → Settings → Plugins → Search for "Claude Code" and install

# Configuration
# File → Settings → Tools → Claude Code

Key Features

public class UserService {
    // Invoke Claude Code with Alt+C
    // "Add JWT authentication and role-based access control to this class"

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private JwtTokenUtil jwtTokenUtil;

    public ResponseEntity<User> authenticateUser(LoginRequest request) {
        // Authentication logic auto-generated by Claude Code
    }
}

⚡ Latest API Features

Claude Opus 4 Support

# Specify latest model
claude --model claude-opus-4 "task requiring advanced reasoning"

# Switch model
claude config set default_model claude-opus-4

# Performance comparison test
claude --model claude-opus-4 "complex algorithm implementation" > opus4_result.txt
claude --model claude-3.5-sonnet "complex algorithm implementation" > sonnet_result.txt
diff opus4_result.txt sonnet_result.txt

File API Utilization

# Process large files
claude --file-api "efficiently analyze files over 10MB"

# Concurrent multi-file processing
claude --batch-files src/*.js "check all JavaScript files for ESLint compliance"

# Automatic file diff processing
claude --file-diff "analyze Git diff and generate review comments"

Prompt Caching

# Enable caching
claude config set prompt_caching true

# Project-specific cache
claude --cache-key "project-$(basename $(pwd))" "project analysis"

# Check cache statistics
claude cache stats

🔧 GitHub Actions Integration

Workflow Configuration

# .github/workflows/claude-code-review.yml
name: Claude Code Review

on:
  pull_request:
    types: [opened, synchronize]

jobs:
  claude-review:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Setup Claude Code
        uses: anthropic/claude-code-action@v1
        with:
          api-key: ${{ secrets.ANTHROPIC_API_KEY }}

      - name: Code Review
        run: |
          claude --thinking-mode extended \
            --output markdown \
            "Comprehensively review the pull request changes and
            analyze from the following perspectives:
            1. Code quality and best practices
            2. Security vulnerabilities
            3. Performance impact
            4. Test coverage
            5. Documentation update needs" \
            > review_result.md

      - name: Comment PR
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            const review = fs.readFileSync('review_result.md', 'utf8');
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: review
            });

Auto-Fix Workflow

# .github/workflows/claude-auto-fix.yml
name: Claude Auto Fix

on:
  schedule:
    - cron: '0 2 * * *'  # Run daily at 2 AM

jobs:
  auto-fix:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Auto Fix Issues
        run: |
          claude --thinking-mode extended \
            --auto-commit \
            "Analyze the entire project and auto-fix the following issues:
            1. Fix lint errors
            2. Resolve type errors
            3. Fix security vulnerabilities
            4. Performance optimization"

      - name: Create Pull Request
        if: success()
        uses: peter-evans/create-pull-request@v5
        with:
          title: "🤖 Claude Code Auto-Fix"
          body: "Automatic fixes by Claude Code have been applied"
          branch: claude-auto-fix

🌐 MCP 2.0 Protocol

OAuth Authentication Support

# OAuth setup
claude mcp auth --provider github
claude mcp auth --provider slack
claude mcp auth --provider figma

# Check authentication status
claude mcp auth status

Remote MCP Servers

# Configure remote server
claude mcp add-server \
  --name production-db \
  --url https://mcp.company.com/postgres \
  --auth oauth \
  --transport https

# List servers
claude mcp list-servers

# Data operations via server
claude --mcp production-db "generate customer database analysis report"

# Filesystem integration
claude mcp install filesystem
claude --mcp filesystem "organize project files"

# GitHub integration
claude mcp install github
claude --mcp github "create summary of all repository issues"

# Slack integration
claude mcp install slack
claude --mcp slack "answer team technical questions collectively"

# PostgreSQL integration
claude mcp install postgresql
claude --mcp postgresql "propose database schema optimization"

📱 Claude 3.7 Sonnet Hybrid Reasoning

Feature Overview

Claude 3.7 Sonnet is the market's first hybrid reasoning model, balancing instant responses with visualization of step-by-step thinking processes.

# Use hybrid reasoning mode
claude --model claude-3.7-sonnet --reasoning hybrid "solve complex problem step by step"

# Visualize reasoning process
claude --model claude-3.7-sonnet --show-reasoning "algorithm optimization proposal"

Usage Example

# Claude 3.7 Sonnet step-by-step reasoning
# "Please improve the performance of this code"
def process_data(data):
    # Step 1: Analyze data structure
    # Step 2: Identify bottlenecks
    # Step 3: Generate optimization proposals
    # Step 4: Implement and verify
    pass

🔐 Security Enhancement Features

Permission Management System

# Detailed permission settings
claude permission set \
  --file-access read-only \
  --network-access limited \
  --system-commands deny \
  --api-access approved-only

# Project-specific permissions
claude permission project \
  --name secure-project \
  --no-network \
  --no-file-write \
  --audit-log enabled

Security Audit Features

# Security scan
claude security scan \
  --check-dependencies \
  --check-secrets \
  --check-permissions \
  --generate-report

# Update vulnerability database
claude security update-db

# Generate security report
claude security report --format json > security_report.json

📊 Performance Monitoring

Real-time Monitoring

# Start performance monitoring
claude monitor start \
  --metrics cpu,memory,network \
  --interval 5s \
  --output dashboard

# Check monitoring data
claude monitor stats
claude monitor export --format csv

Auto-Optimization

# Enable auto-optimization
claude optimize auto \
  --memory-management aggressive \
  --cache-optimization enabled \
  --request-batching smart

# Optimization report
claude optimize report

🔄 Migration Support

Migration from Other Tools

# Migrate from GitHub Copilot
claude migrate from-copilot \
  --import-settings \
  --convert-shortcuts \
  --backup-config

# Migrate from Cursor
claude migrate from-cursor \
  --project-settings \
  --custom-prompts \
  --keyboard-shortcuts

💼 Claude Max Plan New Features

Plan Overview

Claude Max is a new subscription plan priced at 100–200/month, offering:

  • Unlimited Claude Code Usage
  • Priority Access: Early access to latest models
  • Extended Context Window: Up to 200K tokens
  • Dedicated Support: Enterprise-level support
# Activate Max plan
claude subscription upgrade --plan max

# Check usage status
claude subscription status

🚀 Implementation Cases and Success Stories

Cloudflare Use Case

A developer's use of Claude Code to write Cloudflare code gained attention. Through prompt engineering, successfully implemented complex edge computing logic.

Thoughtworks Efficiency Case

  • 97% Work Reduction: Automation of routine coding tasks
  • 80% Code Review Time Reduction: Utilizing auto-review features
  • 65% Bug Fix Time Reduction: Root cause analysis via extended thinking mode

🔗 Related Articles

📞 Support for 2025 Features

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