Claude Code has two main extension systems: skills (Markdown files) and MCP servers (protocol-based tools). Both make Claude Code more powerful, but they work differently and are best for different use cases.
This guide covers what each one does, when to use which, how to install them, and the best ones I've found after months of daily use.
What Are Claude Code Skills?
Skills are Markdown files (.md) that you drop into .claude/commands/ in your project. They teach Claude Code how to perform specific tasks — no server, no API, no dependencies.
# Install a skill from TokRepo
npx tokrepo install <skill-name>
# Or manually: just copy a .md file into .claude/commands/
When you type /skillname in Claude Code, it loads the instructions from that file and follows them.
Best for: code review workflows, commit conventions, testing patterns, project-specific rules.
What Are MCP Servers?
MCP (Model Context Protocol) servers are standalone programs that expose tools, resources, and prompts to Claude Code over a standardized protocol. They can connect to databases, APIs, browsers, file systems — anything.
# Add an MCP server
claude mcp add <name> -- npx <package>
Best for: external integrations (databases, APIs, browsers), tools that need runtime state.
Skills vs MCP Servers — Quick Comparison
| Feature | Skills | MCP Servers |
|---|---|---|
| Format | Markdown file | Standalone server process |
| Install | Copy .md file |
claude mcp add command |
| Dependencies | None | Node.js/Python runtime |
| External access | No (text only) | Yes (APIs, DBs, browsers) |
| Portability | Copy-paste | Config per machine |
| Overhead | Zero | Process running in background |
| Best for | Workflows, rules | Integrations, tools |
The 10 Best Claude Code Skills (Tested)
After testing 30+ skills on production codebases, these are the ones I actually keep installed:
1. GSD (Get Stuff Done)
Project management with phase planning, verification, and atomic commits. The most comprehensive skill I've used.
npx tokrepo install gsd
2. Frontend Design
Generates production-grade UI components with proper responsive design. Output quality is noticeably better than unguided Claude.
npx tokrepo install frontend-design
3. Simplify
Reviews your changed code for reuse and efficiency, then auto-fixes. My favorite "set and forget" skill.
4. Commit
Analyzes staged changes and writes why-focused commit messages. Saves 30 seconds per commit.
5. Webapp Testing
Playwright-based testing. Point at localhost, describe what to verify, get working tests.
6. Doc Coauthoring
Structured documentation workflow. Asks the right questions before writing.
7. PDF / XLSX / PPTX
File format skills — read, create, and manipulate office documents from the terminal.
8. Claude API
If you're building with the Anthropic SDK, this skill knows latest patterns and model IDs.
9. MCP Builder
Scaffolds new MCP servers with proper JSON schema. Saved me hours.
10. Skill Creator
Meta: creates new skills. Useful for packaging your team's workflows.
The 8 Best MCP Servers (Tested)
1. Playwright MCP (Microsoft)
Browser automation from Claude Code. Navigate, click, fill forms, take screenshots.
claude mcp add playwright -- npx @anthropic-ai/mcp-playwright
2. GitHub MCP
Full GitHub API access — create PRs, review code, manage issues.
claude mcp add github -- npx @modelcontextprotocol/server-github
3. Filesystem MCP
Secure file operations with configurable access controls.
4. PostgreSQL MCP
Read-only database access with schema inspection. Great for data exploration.
5. Firecrawl MCP
Web scraping and crawling from Claude Code.
6. TokRepo MCP
Search and install AI assets (skills, prompts, workflows) directly from Claude Code. 500+ assets indexed.
claude mcp add tokrepo -- npx tokrepo-mcp-server
7. Sentry MCP
Retrieve and analyze issues from Sentry directly in your coding flow.
8. Memory MCP
Persistent memory across Claude Code sessions using a knowledge graph.
How to Find More Skills and MCP Servers
The hardest part isn't installing — it's finding good ones. Here's where I look:
TokRepo — Free registry with 500+ skills, MCP servers, and workflows. Searchable by category with install commands. Also has step-by-step guides.
GitHub Awesome Lists — awesome-mcp-servers (84K+ stars) and awesome-claude-skills (52K+ stars).
Official MCP Registry — Anthropic's own registry at modelcontextprotocol/registry.
FAQ
How many skills can I install at once?
No hard limit, but each active skill consumes context window space. Keep 5-10 active, disable others when not needed.
Do skills work with Cursor and Codex CLI?
Most Markdown-based skills are portable. TokRepo skills follow the SKILL.md standard that works across Claude Code, Cursor (as .cursorrules), Codex CLI (as AGENTS.md), and Gemini CLI.
Are MCP servers secure?
Each MCP server runs as a separate process with its own permissions. The MCP protocol enforces clear boundaries — servers can't access your filesystem unless you explicitly configure them to.
Can I create my own skill?
Yes! Create a .md file in .claude/commands/ with instructions. See the full tutorial on creating skills.
What's the difference between skills, MCP servers, and CLAUDE.md rules?
- Skills = reusable slash commands (per-project or global)
- MCP servers = external tool integrations (databases, APIs, browsers)
- Rules = always-on project instructions (coding standards, conventions)
See the complete comparison guide for details.
What skills and MCP servers are you using? Drop your setup in the comments — I'm always looking for new ones to test.
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