I’ve tried hundreds of viral Claude skills. These are the five I’d install first if I were running a small business today, with the link, the setup and a first prompt for each.
A skill is a folder of instructions that teaches Claude one job the way a pro would do it. You add it once, and Claude uses it whenever that job comes up. All five of these are free and open source on GitHub.
In the Claude app on any paid plan, open Customize (being renamed Plugins), go to Plugins, click Add, then Add marketplace, and under Add from a repository paste the repo name from the card. (Anthropic’s steps)
On the Free plan, click the green Code button on GitHub, pick Download ZIP and unzip it. Re-zip just one skill folder and upload it under Customize (or Plugins), then Skills, the + button, Create skill, Upload a skill. Turn on code execution under Settings, then Capabilities, first. (Anthropic’s steps)
In Claude Code, paste the install lines from each card. Lines starting with /plugin go inside a Claude Code session. Lines starting with npx go in your terminal and need Node.js. Three of these five are built for Claude Code, because they work on files on your computer. If the terminal scares you, start with my Claude Code starter guide.
Read Before You Install
Skills can run code on your computer with your permissions. Before you install any skill, open its GitHub page, check who made it, and ask Claude to read the files and tell you in plain words what they do. Copycat repos with similar names exist, so use the exact links below. My skills marketplace guide has my full safety checklist.
01
Founder Skill
Test a business before you spend money on it. It’s eleven skills that work as a team. One is a board of directors that scores your idea with the published frameworks of Alex Hormozi, Peter Thiel and Steve Jobs. Another is a consumer panel that spins up 100 simulated buyers modeled on your target customer and tells you who buys, who passes and why. Others handle pricing, a CFO, marketing and a launch plan.
Run them in order and you end with a business plan and a verdict. The author warns the panel leans agreeable, so treat its buy rate as a best case and confirm big calls with real people.
Made by Jake Schincariol. In the Claude app, add the repository Jakeschincariol/founder-skill.
02
Corey Haines’ Marketing Skills
53 marketing skills in one free pack, covering SEO, ads, emails, copywriting, pricing, launches and more. I counted 53 in the repo today. It really is like hiring a marketing team for free.
Start with the product-marketing skill. It writes one file about your business, your customers and your positioning, and every other skill in the pack reads it first, so you stop repeating yourself.
In the Claude app, add the repository coreyhaines31/marketingskills. For which marketing skill to try first by job, see my free skills by department guide.
03
Hallmark
Ask AI for a website and you usually get the same page everyone else gets. Hallmark fixes that. It has 50 design themes (you can browse them all at usehallmark.com), offers you three that fit your business, builds the page around the one thing visitors came to do, then checks it for AI design tells before handing it over. It never makes up facts about your business.
Already have a site? Point it at your page with /hallmark redesign to rebuild it while keeping your content, or /hallmark audit for a report only. Made by Nutlope and Together AI, for Claude Code. My 5 design skills guide has more taste tools to stack with it.
04
Cloudflare’s Security Audit
If you built an app or site with AI, this is the one I wouldn’t skip. It’s Cloudflare’s own skill, the starting point for the vulnerability hunting system they wrote about on their blog. Claude maps your project, sends separate agents to hunt for security holes, then has a fresh agent try to disprove every finding so you only get real problems.
Open Claude Code inside your project folder and ask for the audit. The report lands in a security-audit-skill folder in your home folder. Run it more than once, because in Cloudflare’s tests one run found roughly half of what repeated runs found.
For a check that runs while you build, add Anthropic’s free security plugin too. Taking payments or customer data? Read my startup security checklist.
05
REA: Reverse Engineer Anything
Pick a feature you love in an app you use, like a booking flow. REA has Claude inspect the app without its source code, explain how the feature works, show you the evidence, and build a version for your own project. The analysis runs on your computer.
Run the setup line in your terminal, choose Claude Code, approve the changes and restart Claude Code. Get it only from morluto/rea or rea.tools, because copycats with similar names are out there. Its own rules say to use it only on software you’re allowed to examine, and never to copy a company’s protected code or assets. Rebuild the idea in your own way.
Want skills already built for how a team works? Avori, my company, has a marketplace with hundreds of my agents and skills, and you can get it free inside the platform at getavori.com. There’s a 7-day free trial, and once you’re in, every single thing in the Avori marketplace is free.