Claude Code skills are reusable slash commands that give Claude specific instructions for a task. Instead of prompting from scratch every time, you type /auth and Claude already knows your stack, your patterns, and exactly what to produce.
Here's how to build your own.
What a Skill Is
A skill is a markdown file in your .claude/skills/ directory. When you type /skill-name in Claude Code, it loads that file and uses its contents as the instruction set.
.claude/
skills/
auth.md
pay.md
test.md
deploy.md
Skill File Structure
---
name: auth
description: "Generate a complete authentication system for this project"
---
You are implementing authentication for this project. Follow these steps:
1. Read the existing project structure first
2. Check what auth-related packages are already installed
3. Ask the user 3 questions before writing any code:
- Which providers do you need? (Google, GitHub, email/password)
- Do you need role-based access control?
- Which pages should be protected?
4. Based on the answers, implement:
- NextAuth configuration with chosen providers
- Prisma models for User, Account, Session
- Middleware for protected routes
- Sign in / sign out components
- Session hooks for the frontend
5. Run the migration after creating the schema
6. Write a brief test to verify auth is working
Always match the existing code style and patterns you find in the project.
The frontmatter (name, description) is metadata. Everything after is the instruction Claude follows.
Your First Skill: Test Generator
This skill generates tests for any function:
---
name: test
description: Generate comprehensive tests for a function or module
---
Generate tests for the code the user specifies.
Before writing tests:
1. Read the target file to understand the function signatures and types
2. Find the existing test directory and read 1-2 existing tests to match the pattern
3. Identify the testing framework in use (Jest, Vitest, etc.)
Then generate tests covering:
- Happy path (expected inputs produce expected outputs)
- Edge cases (empty inputs, null, zero, max values)
- Error cases (invalid inputs should throw or return errors)
- Async behavior (if the function is async, test success and failure)
Match the exact import style, describe block naming, and assertion patterns from existing tests.
Run the tests after writing them. If they fail, diagnose and fix before finishing.
Save this as .claude/skills/test.md. Now type /test in Claude Code and specify a function.
A Real Productivity Skill: PR Description Generator
---
name: pr
description: Generate a pull request description from the current git diff
---
Generate a pull request description for the changes in this branch.
Steps:
1. Run `git diff main...HEAD` to see all changes
2. Run `git log main...HEAD --oneline` to see commit history
3. Analyze what changed and why
Write a PR description with:
## Summary
2-3 bullet points covering what changed at a high level.
## Changes
- List each meaningful change with file paths
- Group related changes together
- Skip trivial changes (whitespace, comments)
## Testing
- How was this tested?
- What edge cases were considered?
## Notes
- Any breaking changes?
- Any decisions that need explanation?
- Anything reviewers should pay special attention to?
Keep the total length under 400 words. Be specific, not generic.
Output the description in a markdown code block so it's easy to copy.
A Database Skill: Schema From Plain English
---
name: schema
description: Generate a Prisma schema from a plain English description
---
Generate a Prisma schema based on the user's description.
Before generating:
1. Read the existing prisma/schema.prisma to understand current models and conventions
2. Note the database provider (PostgreSQL, SQLite, etc.)
3. Note naming conventions (camelCase fields, singular model names, etc.)
When generating the new model(s):
- Match the existing naming and convention patterns exactly
- Add appropriate indexes for fields that will be queried
- Add created_at and updated_at timestamps unless the user says not to
- Use @relation for foreign keys
- Add @unique constraints where they make sense semantically
After generating the schema additions:
1. Show the user what will be added and ask for confirmation
2. If confirmed, append to prisma/schema.prisma
3. Run `npx prisma migrate dev --name [descriptive-name]`
4. Verify the migration succeeded
Skill Best Practices
Start with questions, not code. A skill that asks 2-3 targeted questions before writing code produces far better output than one that guesses.
Tell it to read first. Instruct the skill to read existing files before generating anything new. This ensures it matches your patterns.
Specify verification steps. "Run the tests" or "verify the migration succeeded" prevents Claude from stopping at generation without confirming the output works.
Keep skills focused. A skill that does one thing well beats a skill that tries to do everything. /auth for auth, /pay for payments, /test for tests.
Version control them. Commit your .claude/skills/ directory. Skills are part of your project's tooling.
Loading Skills Into Your Session
Skills load automatically when you type their slash command. You can also list available skills:
> /help
Or reference a skill explicitly:
> Use the /test skill on src/lib/rate-limit.ts
The Ship Fast Skill Pack
I've pre-built 10 skills covering the most common development tasks:
-
/auth-- full NextAuth v5 setup with Prisma -
/pay-- Stripe subscriptions and one-time payments -
/deploy-- Docker + GitHub Actions CI/CD -
/test-- test generation matching your existing patterns -
/api-- REST or GraphQL endpoint scaffolding -
/db-- Prisma schema from plain English -
/rate-limit-- API rate limiting with Upstash -
/email-- transactional email with Resend -
/analytics-- usage tracking and dashboard queries -
/docs-- auto-generate API documentation
Each skill is tuned for Next.js 14 App Router but works with any Node.js project.
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