Skills, Plugins, MCP: What's Actually Worth Installing in Claude Code

Search "best Claude Code skills" and you'll get twenty near-identical lists, each one scraped from the last, each citing a different (and usually inflated) star count for the same handful of repos. Most are written by people optimising for the keyword, not the workflow.

This is the short, checked version. Every install command below was verified against the project's own repository or Anthropic's marketplace — and I'll tell you where the popular numbers are quietly lying to you.

First, the thing almost nobody bothers to define.

Three different things, constantly confused

Most "skills" lists lump these together. They are not the same, and they install differently.

• A Skill is a SKILL.md file — instructions, a checklist, a methodology. It follows the open Agent Skills standard and loads only when relevant, so it costs almost nothing until Claude actually needs it. (Custom slash-commands are now just skills under the hood.)
• A Plugin is a bundle — usually one or more skills plus commands — installed from a marketplace in a single command.
• An MCP server is a connection to something outside Claude: live documentation, your database, GitHub, a browser. Different mechanism entirely — it adds tools, not instructions.

Rule of thumb: skills change how Claude works; MCP servers change what Claude can reach. Once that clicks, the marketplace stops looking like noise.

The five I'd actually install

Superpowers — the methodology heavyweight

Jesse Vincent's framework turns Claude from an eager code-generator into something that brainstorms, writes a plan, does test-driven development, and reviews its own work. It's a bundle of composable skills — TDD, systematic-debugging, verification-before-completion, parallel subagents, git-worktrees — and it's in Anthropic's official marketplace:

/plugin install superpowers@claude-plugins-official

Worth it on real projects; overkill for a one-off script.

Frontend Design — stop the generic-AI look

Anthropic's own skill. Without it, Claude reaches for the same Inter-font / purple-gradient / card-grid layout every single time. With it you get distinctive typography, deliberate colour, and real animation. It loads itself whenever you build a UI:

/plugin marketplace add anthropics/claude-code
/plugin install frontend-design@claude-code-plugins

Context7 — kill stale documentation

An MCP server that injects up-to-date, version-specific library docs into the session, instead of letting Claude guess from training data that's months old. Add use context7 to a prompt and it fetches the real, current API:

claude mcp add context7 -- npx -y @upstash/context7-mcp@latest

Karpathy Guidelines — a behaviour patch

After Andrej Karpathy listed the classic LLM-coding failure modes in January 2026, Forrest Chang turned them into a tiny rules file. (Karpathy didn't write it — worth knowing before you repeat the myth.) Four principles: think before coding, simplicity first, surgical changes, goal-driven execution. Install it as a plugin, or just drop the CLAUDE.md straight into a project:

/plugin marketplace add forrestchang/andrej-karpathy-skills
/plugin install andrej-karpathy-skills@karpathy-skills

Caveman — useful, but read the small print

This one tells Claude to drop articles, filler and narration to save output tokens. The headline — "cuts 65% of tokens" — is true, of prose tokens. But prose is a thin slice of a real session; most tokens are input: your code, context and history. The honest maths: 65% off the ~6% of a session that's prose works out to roughly 4% saved overall. The author says as much in the repo; the listicles don't:

claude plugin marketplace add JuliusBrussee/caveman
claude plugin install caveman@caveman

A fine quality-of-life tweak — but not the bill-slashing trick the headlines sell. For that, see the field guide: context discipline is where the money actually is.

Don't install thirty of them

The ecosystem rewards collectors, but every extra skill is more surface area for Claude to reason about. The working consensus among heavy users is that eight to twelve well-chosen skills cover most of a senior developer's day. Install deliberately, and uninstall anything you haven't invoked in a fortnight.

A word on the numbers

If you cite a star count, pull it live the day you publish. While researching this piece I saw Superpowers quoted at 94K, 150K and 235K across three articles, and the Karpathy file at 100K, 109K and 180K — for a repository that is one markdown file. The content farms inflate, copy, and re-copy each other. The marketplace shifts weekly, too; verify a command at the source before trusting a screenshot from three months ago.

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That's the honest shortlist. The companion piece — Stop Burning Tokens — covers the habits that actually cut your Claude Code bill, with an interactive quiz to test yourself.

Install commands, marketplaces and star counts change fast — verify at the linked repositories and code.claude.com/docs before relying on them.