Claude Code Tips

// Be Specific

1. Be Specific with Your Requests

80% of Claude Code's quality depends on how you describe what you need.

Optimize this function

Too vague. Claude Code doesn't know what to optimize — performance? Readability? Memory? Compatibility?

Optimize this function's performance:
- Currently processes 10,000 records in 3 seconds, target is under 500ms
- Don't change the function signature or return type
- Prefer algorithm optimization over caching

The 5W1H Framework

The more specific your description, the more accurate the result — and fewer back-and-forth rounds means fewer tokens wasted.

// @References

2. Master the @ Syntax for Context

Claude Code supports @ references to point it at exactly the right files.

Common @ Commands

@file.ts          # Reference a single file
@src/utils/       # Reference an entire directory
@package.json     # Reference a config file
@git diff         # Reference Git diff
@git log -5       # Reference last 5 commits

Why This Saves Tokens

• No need to copy-paste code into the conversation
• Claude Code only reads referenced files, not the entire project
• Avoids misunderstandings from insufficient context

@src/api/user.ts Add pagination to this module,
following the same pattern as @src/api/order.ts

// One Task

3. One Task at a Time

This is the most overlooked token-saving technique.

Help me:
1. Add pagination to user module
2. Write unit tests
3. Optimize API response speed
4. Update the frontend list component
5. Update docs

Too many tasks at once — Claude Code will likely miss requirements, produce inconsistent code, generate lots of unnecessary code, and burn through tokens.

Step 1: Add pagination to user module, 20 items per page, with page number navigation

Step 2: Write unit tests for the pagination feature we just built

// CLAUDE.md

4. Use CLAUDE.md for Project Memory

Claude Code reads a CLAUDE.md file in your project root for persistent context.

What to Put in CLAUDE.md

# Project Overview

- Tech stack: Next.js 14 + TypeScript + Prisma + PostgreSQL
- Code style: ESLint + Prettier, single quotes, 2-space indent
- Naming: PascalCase for components, camelCase for functions
- Test framework: Vitest
- API style: RESTful, response format: { code, data, message }
- Don't modify migration files
- Commit format: feat/fix/docs: description

Why This Matters

• Claude Code reads CLAUDE.md automatically every session
• No need to repeat project conventions each time
• Generated code stays consistent
• Significantly reduces back-and-forth token usage

// Slash Commands

5. Use Built-In Slash Commands

Claude Code includes slash commands that save time and tokens.

When to Use /compact

When the conversation gets long and Claude Code starts "forgetting" earlier agreements, run /compact. It compresses history while keeping key information, dramatically reducing token consumption for future requests.

// Plan First

6. Let Claude Code Plan Before Coding

A common mistake: asking Claude Code to write code immediately.

First, review @src/api/user.ts and @src/types/user.d.ts
to understand the existing user module structure.
Then tell me how you plan to implement pagination.
I'll confirm before you start coding.

• Avoids code that doesn't match expectations
• Reduces "write, discard, rewrite" token waste
• You catch misaligned thinking early

// Model Selection

7. Choose the Right Model

Cost Strategy

• Haiku for simple tasks: Rename a variable, format code, write a simple function
• Sonnet for daily work: Feature development, bug fixes, write tests
• Opus for complex tasks only: Architecture design, large-scale refactoring, complex algorithms

Switch models: /model claude-3-haiku-20240307

// Avoid Waste

8. Avoid Common Token Wastes

// Prompt Templates

9. Ready-to-Use Prompt Templates

Here are battle-tested prompt templates you can copy directly:

In @src/api/user.ts, add a function to look up users by email.
Requirements:
- Function name: getUserByEmail
- Parameter: email: string
- Return: User | null
- Return null if user doesn't exist, don't throw
- Follow the style of the existing getUserById function

The createOrder function at line 45 in @src/api/order.ts
produces duplicate inserts under concurrent calls.
Investigate and fix this issue.
Only modify the minimum necessary code, don't refactor anything else.

Write unit tests for validateEmail and validatePhone in @src/utils/validate.ts.
Requirements:
- Use Vitest
- Cover normal cases and edge cases
- Place the test file in the same directory as validate.test.ts

Review my recent changes @git diff.
Focus on:
1. Security vulnerabilities (SQL injection, XSS)
2. Performance issues
3. Compliance with project code standards
Only list genuine issues, don't nitpick.

// Token Comparison

10. Token Usage Comparison

Same requirement, three different approaches:

// Summary

Summary

Claude Code efficiency comes down to three things:

Build these habits and your productivity (and token efficiency) will improve dramatically.