Navigate to the project root directory

cd /path/to/project 

Start Claude Code

claude 

Ask for a high-level overview

> give me an overview of this codebase 

Dive deeper into specific components

> explain the main architecture patterns used here 

> what are the key data models?

> how is authentication handled?

Ask Claude to find relevant files

> find the files that handle user authentication 

Get context on how components interact

> how do these authentication files work together? 

Understand the execution flow

> trace the login process from front-end to database 

Share the error with Claude

> I'm seeing an error when I run npm test 

Ask for fix recommendations

> suggest a few ways to fix the @ts-ignore in user.ts 

Apply the fix

> update user.ts to add the null check you suggested 

Identify legacy code for refactoring

> find deprecated API usage in our codebase 

Get refactoring recommendations

> suggest how to refactor utils.js to use modern JavaScript features 

Apply the changes safely

> refactor utils.js to use ES2024 features while maintaining the same behavior 

Verify the refactoring

> run tests for the refactored code 

View available subagents

> /agents

This shows all available subagents and lets you create new ones.

Use subagents automatically

Claude Code will automatically delegate appropriate tasks to specialized subagents:

> review my recent code changes for security issues

> run all tests and fix any failures

Explicitly request specific subagents

> use the code-reviewer subagent to check the auth module

> have the debugger subagent investigate why users can't log in

Create custom subagents for your workflow

> /agents

Then select "Create New subagent" and follow the prompts to define:

• Subagent type (e.g., api-designer, performance-optimizer)
• When to use it
• Which tools it can access
• Its specialized system prompt

Identify untested code

> find functions in NotificationsService.swift that are not covered by tests 

Generate test scaffolding

> add tests for the notification service 

Add meaningful test cases

> add test cases for edge conditions in the notification service 

Run and verify tests

> run the new tests and fix any failures 

Summarize your changes

> summarize the changes I've made to the authentication module 

Generate a PR with Claude

> create a pr 

Review and refine

> enhance the PR description with more context about the security improvements 

Add testing details

> add information about how these changes were tested 

Identify undocumented code

> find functions without proper JSDoc comments in the auth module 

Generate documentation

> add JSDoc comments to the undocumented functions in auth.js 

Review and enhance

> improve the generated documentation with more context and examples 

Verify documentation

> check if the documentation follows our project standards 

Add an image to the conversation

You can use any of these methods:

1. Drag and drop an image into the Claude Code window
2. Copy an image and paste it into the CLI with ctrl+v (Do not use cmd+v)
3. Provide an image path to Claude. E.g., "Analyze this image: /path/to/your/image.png"

Ask Claude to analyze the image

> What does this image show?

> Describe the UI elements in this screenshot

> Are there any problematic elements in this diagram?

Use images for context

> Here's a screenshot of the error. What's causing it?

> This is our current database schema. How should we modify it for the new feature?

Get code suggestions from visual content

> Generate CSS to match this design mockup

> What HTML structure would recreate this component?

Reference a single file

> Explain the logic in @src/utils/auth.js

This includes the full content of the file in the conversation.

Reference a directory

> What's the structure of @src/components?

This provides a directory listing with file information.

Reference MCP resources

> Show me the data from @github:repos/owner/repo/issues

This fetches data from connected MCP servers using the format @server:resource. See MCP resources for details.

Provide context and ask Claude to think

> I need to implement a new authentication system using OAuth2 for our API. Think deeply about the best approach for implementing this in our codebase.

Claude will gather relevant information from your codebase and use extended thinking, which will be visible in the interface.

Refine the thinking with follow-up prompts

> think about potential security vulnerabilities in this approach 

> think hard about edge cases we should handle 

Continue the most recent conversation

claude --continue

This immediately resumes your most recent conversation without any prompts.

Continue in non-interactive mode

claude --continue --print "Continue with my task"

Use --print with --continue to resume the most recent conversation in non-interactive mode, perfect for scripts or automation.

Show conversation picker

claude --resume

This displays an interactive conversation selector with a clean list view showing:

• Session summary (or initial prompt)
• Metadata: time elapsed, message count, and git branch

Use arrow keys to navigate and press Enter to select a conversation. Press Esc to exit.

Understand Git worktrees

Git worktrees allow you to check out multiple branches from the same repository into separate directories. Each worktree has its own working directory with isolated files, while sharing the same Git history. Learn more in the official Git worktree documentation.

Create a new worktree

# Create a new worktree with a new branch 
git worktree add ../project-feature-a -b feature-a

# Or create a worktree with an existing branch
git worktree add ../project-bugfix bugfix-123

This creates a new directory with a separate working copy of your repository.

Run Claude Code in each worktree

# Navigate to your worktree 
cd ../project-feature-a

# Run Claude Code in this isolated environment
claude

Run Claude in another worktree

cd ../project-bugfix
claude

Manage your worktrees

# List all worktrees
git worktree list

# Remove a worktree when done
git worktree remove ../project-feature-a

Use text format (default)

cat data.txt | claude -p 'summarize this data' --output-format text > summary.txt

This outputs just Claude's plain text response (default behavior).

Use JSON format

cat code.py | claude -p 'analyze this code for bugs' --output-format json > analysis.json

This outputs a JSON array of messages with metadata including cost and duration.

Use streaming JSON format

cat log.txt | claude -p 'parse this log file for errors' --output-format stream-json

This outputs a series of JSON objects in real-time as Claude processes the request. Each message is a valid JSON object, but the entire output is not valid JSON if concatenated.

Create a commands directory in your project

mkdir -p .claude/commands

Create a Markdown file for each command

echo "Analyze the performance of this code and suggest three specific optimizations:" > .claude/commands/optimize.md 

Use your custom command in Claude Code

> /optimize 

Create a command file with the $ARGUMENTS placeholder

echo 'Find and fix issue #$ARGUMENTS. Follow these steps: 1.
Understand the issue described in the ticket 2. Locate the relevant code in
our codebase 3. Implement a solution that addresses the root cause 4. Add
appropriate tests 5. Prepare a concise PR description' >
.claude/commands/fix-issue.md 

Use the command with an issue number

In your Claude session, use the command with arguments.

> /fix-issue 123 

This will replace $ARGUMENTS with "123" in the prompt.

Create a commands directory in your home folder

mkdir -p ~/.claude/commands 

Create a Markdown file for each command

echo "Review this code for security vulnerabilities, focusing on:" >
~/.claude/commands/security-review.md 

Use your personal custom command

> /security-review