Claude Code is a CLI tool that lets Claude read, write, and execute code in your project. It's not just autocomplete — it's an agent that can plan, execute, and iterate. Here's how to actually use it effectively.
Installation and Setup
npm install -g @anthropic-ai/claude-code
claude # starts interactive session
Claude Code reads your project files automatically. It understands your codebase structure from the first message.
Core Interaction Patterns
Implementation requests:
"Add rate limiting to the /api/ai/chat route. Use Redis with a sliding window.
100 requests per hour per IP. Return 429 with Retry-After header."
Debugging:
"The Stripe webhook handler is throwing an error. The logs show:
Error: No signatures found matching the expected signature for payload
Here's the route: [paste code]"
Refactoring:
"The getUserById and getUserByEmail functions share 80% of their code.
Extract the common logic into a base getUser function."
Effective Prompting for Code
Be specific about constraints:
Bad: "Add authentication"
Good: "Add NextAuth with Google OAuth. Use the Prisma adapter.
Protect /dashboard/* and /api/protected/*.
After login, redirect to /dashboard.
The user schema is in prisma/schema.prisma."
Context is everything. The more you give, the less Claude has to guess.
Multi-File Tasks
Claude Code can work across your entire codebase:
"I need to add a subscription tier check to all premium routes.
Premium routes are marked with a comment: // PREMIUM ROUTE
Check if the user has an active subscription before processing.
Use the existing requireAuth middleware pattern in middleware.ts."
Claude will find all the relevant files, understand the existing patterns, and apply them consistently.
Using Skills (Slash Commands)
Claude Code supports custom skills that give it specialized context:
/auth → generates complete auth setup for your stack
/pay → wires up Stripe checkout and webhook handling
/deploy → creates Docker, CI/CD, and deployment configs
/test → generates test suite for any function or component
/api → scaffolds REST or GraphQL endpoints
# In Claude Code
/auth
# Claude asks: What providers? (Google, GitHub, email?)
# Claude asks: Using NextAuth or custom?
# Claude generates: complete auth implementation
The Review Workflow
1. Describe the task clearly
2. Claude proposes an approach -- read it before accepting
3. Claude implements -- review the diff
4. Run tests: npm test
5. Spot-check the code manually
6. Commit with a descriptive message
Never blindly accept Claude's output. Review every change.
CLAUDE.md: Project Instructions
# CLAUDE.md
## Project
Next.js 14 AI SaaS. Stack: TypeScript, Prisma, NextAuth, Stripe, Tailwind, shadcn/ui.
## Conventions
- Use Server Components by default, 'use client' only when needed
- All API routes validate with Zod
- Error handling via centralized handler in lib/errors.ts
- Tests in __tests__/ with Vitest
## Do Not
- No console.log in production code (use logger)
- No any types without a comment explaining why
- No direct db calls in components (use server actions or API routes)
CLAUDE.md is read at the start of every session. It's how you encode your project's standards.
Agentic Mode
For larger tasks, Claude Code can plan and execute autonomously:
"I need to add a complete invoicing system. Requirements:
- Users can create invoices with line items
- PDF generation
- Email delivery to clients
- Payment tracking (paid/unpaid/overdue)
- Dashboard view
Plan the implementation first, then execute."
Claude will propose a multi-step plan, wait for your approval, then implement each step.
The Ship Fast Skill Pack at whoffagents.com gives Claude Code 10 specialized skills — /auth, /pay, /deploy, /test, and more. Install once, use on every project. $49 one-time.
