Claude AI - Complete Usage Guide¶

1. Overview¶

What is Claude?

Claude is an advanced AI assistant developed by Anthropic. It excels at natural language understanding, code generation, analysis, creative writing, and complex reasoning tasks. Claude is available both as a web interface and as a command-line tool (Claude Code).

Official Resources:

Web Interface: https://claude.ai/
Claude Code (CLI): https://claude.com/code
API Documentation: https://docs.anthropic.com/

Key Features:

Natural conversation and context understanding
Code generation and debugging across multiple programming languages
Document analysis and summarization (supports PDF, images, text files)
Long-form content creation
Multi-turn conversations with context retention
Command-line interface for developers (Claude Code)

2. Getting Started¶

2.1 Claude Web Interface¶

Visit https://claude.ai/
Sign up using email, Google account, or other supported methods
Verify your email if required
Start chatting immediately after login

Free vs Pro Plans

Claude offers both free and paid subscription tiers. Claude Pro provides higher usage limits, priority access, and early access to new features.

2.2 Claude Code (CLI)¶

Claude Code CLI

Claude Code is a command-line interface that brings Claude AI directly into your terminal and development workflow. It's designed for developers who prefer working in the command line.

Installation: Visit https://claude.com/code for installation instructions.

3. Claude Code Commands¶

Essential Commands

These commands help you manage your Claude Code sessions effectively.

3.1 Project Management¶

Command	Description
`/init`	Create the `CLAUDE.md` file in your project
`/compact`	Compress the `CLAUDE.md` file to make the AI more focused
`/clear`	Clear conversation history and free up context

CLAUDE.md File

The CLAUDE.md file provides project-specific instructions to Claude Code. Use /init to create it and customize it with your project guidelines.

3.2 Session Control¶

Command	Description
`claude -p`	Start a temporary conversation session
`/resume`	Resume a previous conversation
`/agents`	Create a sub-agent for the project
`/ide`	Launch IDE integration mode

3.3 Conversation Modifiers¶

When interacting with Claude Code, you can use special keywords to enhance responses:

Modifier	Effect
`think`	Ask AI to think about the question
`think hard`	Request deeper analysis
`think harder`	Request even more thorough reasoning
`ultra think`	Maximum reasoning depth

Using Modifiers

# Basic question
How should I structure this API?

# With thinking modifier
think hard: How should I structure this RESTful API for scalability?

3.4 Special Symbols¶

Symbol	Purpose	Example
`!`	Bash mode - informs AI of installed apps to avoid repeat installations	`! I've already installed Docker`
`#`	Add to memory - creates long-term memory for the AI	`# This project uses Python 3.11`

Memory Management

Use # to save important project context that should persist across sessions. This helps Claude remember key decisions and setup details.

4. MCP (Model Context Protocol) Commands¶

What is MCP?

MCP (Model Context Protocol) allows Claude to integrate with external tools and services, extending its capabilities beyond the core AI functionality.

4.1 Basic MCP Commands¶

Command	Description
`claude mcp add <mcpname>`	Add a new MCP server
`claude mcp list`	View all installed MCP servers
`claude mcp remove <mcpname>`	Remove an MCP server

Finding MCP Servers

Discover available MCP servers at: Awesome MCP Servers

4.2 MCP Examples¶

# Add a database MCP
claude mcp add neon

# List all MCPs
claude mcp list

# Remove an MCP
claude mcp remove neon

4.3 MCP Permissions¶

When working with MCPs, you can manage permissions:

Allow: Grant permission for MCP to execute actions
Deny: Block MCP from executing actions

Using MCP in Conversation

You can reference MCPs directly in your prompts:

1	`Use mcp__neon to query the database for user statistics`

5. Custom Slash Commands¶

Create Your Own Commands

Claude Code allows you to create custom slash commands tailored to your workflow.

5.1 Setup¶

Navigate to your .claude directory
Create a commands folder if it doesn't exist
Create markdown files for each command
The filename becomes the command name

5.2 Command Structure¶

Create a file in .claude/commands/ with natural language instructions:

Example: .claude/commands/code_review.md

1	`对比这个分支 $ARGUMENTS，与 main 分支的差异，提出 review 意见`

Usage:

1	`/code_review feature-branch`

5.3 Variables in Commands¶

Variable	Description
`$ARGUMENTS`	Passes arguments to the command
`$PROJECT_PATH`	Current project directory path
`$FILE`	Current file being worked on

5.4 Example Custom Commands¶

.claude/commands/test.md

1 2	`Run all unit tests for the current project and report any failures. If tests fail, suggest fixes for the failing tests.`

.claude/commands/deploy.md

Run build command
Check for build errors
If successful, provide deployment checklist
Remind about environment variables and secrets

.claude/commands/refactor.md

Analyze the file $FILE and suggest refactoring improvements:
- Code organization
- Performance optimizations
- Best practices
- Potential bugs

Command Best Practices

Use clear, descriptive filenames
Write detailed instructions in natural language
Include expected inputs and outputs
Test commands before relying on them in production workflows

6. Core AI Capabilities¶

6.1 Code Generation¶

Claude excels at generating code across multiple programming languages.

Supported Languages:

Python, JavaScript, TypeScript, Java, C++, C#, Go, Rust
HTML, CSS, SQL
Shell scripting (Bash, PowerShell)
And many more

Code Generation Request

1 2	`Write a Python function to validate email addresses using regex, with comprehensive error handling and unit tests`

6.2 Code Review and Debugging¶

Claude can analyze existing code and suggest improvements.

Capabilities:

Bug detection and fixes
Performance optimization suggestions
Code style and best practice recommendations
Security vulnerability identification

Always Test Generated Code

While Claude provides high-quality code, always review and test it thoroughly before deploying to production.

6.3 Document Analysis¶

Upload and analyze various document types:

PDFs
Images (code screenshots, diagrams)
Text files
Markdown files
Code repositories

Example Workflow:

# Attach file and ask
Analyze this API documentation and create a Python client library

7. Advanced Usage Tips¶

7.1 Effective Prompting¶

Writing Better Prompts

The quality of responses depends on how you phrase questions.

Be Specific:

1
2
3

❌ "Fix my code"
✅ "This Python function raises a KeyError when the 'age' key is missing.
   Add error handling and return None for missing keys. Code: [paste]"

Provide Context:

1
2
3

❌ "How do I deploy this?"
✅ "I have a Node.js Express app with PostgreSQL database.
   How should I deploy it to AWS using Docker containers?"

Request Step-by-Step:

I need to build a REST API. Please:
1. Recommend a tech stack for Python
2. Show project structure
3. Provide example endpoints for CRUD operations
4. Include authentication middleware
5. Add error handling best practices

7.2 Multi-Turn Problem Solving¶

Claude excels at iterative problem-solving:

# Initial query
How do I scrape product prices from an e-commerce site?

# Follow-up 1
It's for daily price tracking. What tools should I use?

# Follow-up 2
Show me how to handle pagination

# Follow-up 3
How do I store the data efficiently?

Context Retention

Claude remembers the conversation context, so you can build on previous responses without repeating information.

7.3 Using Claude as a Learning Tool¶

Ask "Why" and "How": Understand the reasoning, not just the solution
Request Analogies: "Explain Kubernetes using a restaurant analogy"
Progressive Learning: Start simple, then go deeper
Practice Problems: Ask for exercises with solutions

8. Project-Specific Configuration¶

8.1 CLAUDE.md File Structure¶

Create a CLAUDE.md file in your project root to provide context:

# Project Name

## Overview
Brief description of the project

## Tech Stack
- Frontend: React + TypeScript
- Backend: Python FastAPI
- Database: PostgreSQL
- Deployment: Docker + AWS

## Code Style
- Use ESLint and Prettier for JavaScript/TypeScript
- Follow PEP 8 for Python
- All functions must have docstrings

## Important Notes
- API keys are stored in .env file
- Never commit credentials to git
- Run tests before committing: `npm test`

## Common Commands
- Start dev server: `npm run dev`
- Run tests: `npm test`
- Build for production: `npm run build`

Keep CLAUDE.md Updated

Regularly update this file as your project evolves. Use /compact to optimize it when it gets too large.

8.2 Git Integration¶

Claude Code can work with Git:

# Review changes
Show me the diff for the last commit

# Analyze branch
Compare feature-branch with main and suggest improvements

# Generate commit message
Create a commit message for these changes: [describe changes]

9. Limitations and Considerations¶

What Claude Cannot Do

9.1 No Real-Time Data Access¶

Cannot browse the internet in real-time
Knowledge cutoff: January 2025
Cannot provide current weather, stock prices, or live news

9.2 No Code Execution¶

Cannot run or test code directly
Cannot install packages or verify functionality
You must test generated code in your own environment

9.3 Accuracy Considerations¶

Always Verify

Verify critical facts from authoritative sources
Test code before deploying to production
Cross-check technical specifications
Review security-sensitive code carefully

10. Privacy and Security¶

Data Privacy

Never share:

Passwords or API keys
Private credentials
Sensitive personal information
Proprietary business data

Best Practices:

Use placeholders for sensitive data (e.g., YOUR_API_KEY_HERE)
Sanitize code before sharing (remove real credentials, database URLs)
Review Anthropic's privacy policy: https://www.anthropic.com/privacy

11. Claude API (For Developers)¶

Programmatic Access

Integrate Claude into your applications using the API.

11.1 Getting Started¶

Visit https://console.anthropic.com/
Sign up for API access
Generate API keys
Review documentation and pricing

11.2 Basic API Example (Python)¶

import anthropic

client = anthropic.Anthropic(
    api_key="your-api-key-here",
)

message = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[
        {"role": "user", "content": "Explain async/await in Python"}
    ]
)

print(message.content)

11.3 Available Models¶

Model	Description	Best For
Claude 3.5 Sonnet	Balanced performance and capability	Complex tasks, coding, analysis
Claude 3 Opus	Highest intelligence	Most difficult reasoning tasks
Claude 3 Haiku	Fastest, most compact	Simple queries, high-volume tasks

API Documentation

Complete API docs: https://docs.anthropic.com/

12. Troubleshooting¶

Issue	Possible Cause	Solution
Response too generic	Prompt lacks specificity	Add more context and details
Code doesn't work	Environment differences	Review, test, provide error messages
Response incomplete	Hit length limit	Ask Claude to continue
Wrong information	Hallucination or outdated knowledge	Verify from authoritative sources
Context lost	Too many messages	Start new conversation with summary

Getting Unstuck

If Claude's responses aren't helpful:

Rephrase your question with more context
Break the problem into smaller parts
Provide examples of what you're looking for
Use modifiers like think hard for complex problems

13. Best Practices Summary¶

Maximize Effectiveness

Be Clear and Specific: Detailed context gets better results
Iterate and Refine: Use follow-up questions
Verify Critical Information: Double-check important facts
Leverage Context: Reference previous messages
Use Structured Prompts: Break complex tasks into steps
Provide Examples: Show what you're looking for
Test Generated Code: Never deploy untested code
Protect Sensitive Data: Don't share credentials
Use Custom Commands: Automate repetitive workflows
Keep CLAUDE.md Updated: Maintain project context

14. Resources¶

Official Resources¶

Claude Web: https://claude.ai/
Claude Code: https://claude.com/code
Anthropic: https://www.anthropic.com/
API Docs: https://docs.anthropic.com/
Support: Available through the Claude interface

Community Resources¶

Discord: Check Anthropic's website for community links
Twitter/X: @AnthropicAI
MCP Servers: Awesome MCP Servers

15. Conclusion¶

Claude AI, whether through the web interface, CLI (Claude Code), or API, is a powerful tool for developers, writers, researchers, and learners. By mastering commands, custom workflows, and effective prompting techniques, you can significantly enhance your productivity and problem-solving capabilities.

Key Takeaways

Start with basic commands and gradually explore advanced features
Customize with CLAUDE.md and slash commands for your projects
Use MCP servers to extend capabilities
Always verify and test AI-generated code
Protect sensitive information
Experiment and iterate to find what works best for you

Last Updated: 2025-10-07 Version: 1.0 Author: Jian Xu