AI Agent (3) — Claude Skills: Modular Agents That Plug Into Your Work
In this guide, you will learn what Claude Skills are, how they differ from regular prompts, where to find ready-made Skills (Anthropic's official marketplace, Agensi, LobeHub, and others), how to install one in under 60 seconds, and how to build your own Skill from scratch — all without writing code.
Difficulty: ★★☆☆☆ (Light hands-on; no coding required to use Skills)
Required Tools: Claude Pro account + Claude Code CLI or Cowork desktop app
Updated: May 2026
Overview
Article 02 introduced Claude Skills as one of the five accessible agent features. This article goes deep. Skills are the most under-used feature in Claude Pro by a wide margin — most subscribers don't realize they exist, even though they're free, easy to install, and dramatically reduce the friction of repeating tasks. The concept is simple: a Skill is a packaged recipe that tells Claude how to behave like a specialist for one specific kind of task. You install it once, then call it from any chat with a slash command (/skill-name) — no copy-pasting prompts from Notion, no re-explaining your context, no hunting for that great prompt you wrote last month.
The standout fact about Claude Skills in 2026 is that they're cross-platform. Anthropic introduced the open SKILL.md specification in late 2025, and OpenAI adopted the exact same format for ChatGPT Codex shortly after. That makes a Skill genuinely portable — one file that works in Claude Code, Cowork, OpenAI Codex CLI, ChatGPT, GitHub Copilot, Cursor, and over a dozen other platforms. The marketplaces have responded: ClaudeSkills.info alone hosts 658+ free Skills, Agensi runs the paid Skills marketplace with Stripe payouts, and Anthropic maintains a public GitHub repository with official examples.
In this article, we'll cover what's inside a Skill (you'll see exactly what the recipe file looks like), where to find good Skills, how to install one in under a minute, and how to write your own when no existing Skill fits your need. By the end, you'll have at least one Skill installed and one of your own custom Skills running.
Who This Is Useful For
What You Will Learn
By the end of this article, you'll be able to do five things:
What You Need
Step 1 — What a Skill Actually Is (And Isn't)
A Claude Skill is a small folder containing one essential file — SKILL.md — and optionally a few extra files (templates, scripts, reference material). The folder lives in a designated Skills directory on your computer. When you start a conversation in Claude Code or Cowork, Claude scans your installed Skills and makes them available as commands. You invoke a Skill by typing /skill-name or by mentioning it in a longer prompt; Claude loads the Skill's instructions and acts as that specialist for as long as the task lasts.
The conceptual model that helps most people: a Skill is like hiring a contractor for a specific job. Regular Claude is a generalist — smart, but with no specific instructions for how to handle your particular use case. A Skill is a contractor with a tightly written job description, a sample portfolio of past work, and clear rules about what to do and not to do. When you call the contractor (/customer-support-reply), they show up already trained for that job. When the job's done, you can call a different contractor (/meeting-notes-cleanup) for a different kind of work.
Skills are not the same as four other things people often confuse them with:
Step 2 — The Anatomy of a SKILL.md File
Most non-technical users have never opened a SKILL.md file and assume it's intimidating. It isn't. The file is plain text written in Markdown (the same format used by README files on GitHub, Notion documents exported as Markdown, and many other tools). A working Skill file has five clearly labeled sections, and you don't need to write a single line of code to create one.
Here's the actual structure of a typical Skill file. Don't worry about memorizing it — you'll be filling in a template, not writing from scratch.
The five sections, plain English:
Step 3 — Where Skills Live: Three Installation Methods
Skills live in a designated folder on your computer. Once Claude Code or Cowork knows about that folder, the Skills inside become available in every chat. There are three places Skills can live, and each fits a different use case.
Location 1: Personal Skills (~/.claude/skills/). This is the most common place to install Skills. Anything in this folder is available across every project on your computer. Use this for general-purpose Skills — translation polishers, meeting notes cleanups, voice tuners — that aren't tied to a specific job or codebase.
Location 2: Project-Level Skills (.claude/skills/ inside a project folder). When you put a Skill inside a project's own .claude/skills/ folder, the Skill only loads when you're working in that project. Use this for Skills that are specific to one client, one codebase, or one job. The advantage: you can commit project Skills to Git and share them with teammates automatically — anyone who clones the repo gets the same Skills.
Location 3: Plugin/Marketplace Skills (installed via /plugin commands). Claude Code has a built-in plugin system. Marketplaces like Anthropic's official one and Agensi let you install Skills with a single command — for example: /plugin marketplace add anthropics/skills to subscribe to the official marketplace, then /plugin install meeting-notes-cleanup to install a specific Skill. This is the fastest method for most users.
For non-technical users, the easiest workflow is:
1. Find a Skill you want from a marketplace (we'll cover marketplaces in Step 4)
2. Use Claude Code or Cowork's built-in installer (Step 5)
3. The Skill goes into your personal Skills folder automatically
4. Restart Claude Code or Cowork (or just open a new chat)
5. The Skill is now available as /skill-name
Step 4 — Browse the Skill Marketplaces
Four major marketplaces in 2026, each with a slightly different focus.
Anthropic's Official Marketplace (github.com/anthropics/skills). The reference implementation. Hosts the official template Skill plus a curated set of high-quality examples. Best for: learning what good Skills look like; finding well-maintained Skills for common tasks. Free; open-source. The starting point for newcomers.
ClaudeSkills.info (claudeskills.info/skills). The largest free Skill directory in 2026, with 658+ Skills as of mid-year. Skills are organized by category (Software Engineering, Writing, Research, Design, Data Analysis, etc.) and include browser previews so you can see what each Skill does before installing. Best for: discovering free Skills across many domains; finding well-rated community-built Skills.
Agensi (agensi.io). The paid Skill marketplace. Works like a Stripe-backed app store for Skills — creators publish, set prices, and Agensi handles payments, security scans, and distribution. Skills typically cost €5–15, with creators receiving 80% of each sale. Best for: finding professionally-built specialist Skills (e.g., AWS security audit, contract red-flag finder, niche-industry research) where the quality bar matters; for builders who want to monetize their Skills.
LobeHub Agent Skills Marketplace (lobehub.com/skills). A multi-platform marketplace that supports Skills compatible with Claude Code, OpenAI Codex CLI, and ChatGPT. Skills are tagged by platform compatibility. Best for: finding Skills that work across multiple AI coding assistants if you switch between platforms.
SkillsMP (skillsmp.com). A newer player focused on agent-skill discovery and ratings, with a community review system. Best for: gauging Skill quality through user reviews before installing.
Step 5 — Install Your First Skill in 60 Seconds
Let's actually install one. We'll use Anthropic's official marketplace and install a useful starter Skill.
Open Claude Code in your terminal (or Cowork's chat panel). Type:
/plugin marketplace add anthropics/skills
This subscribes you to Anthropic's official marketplace. You'll see a confirmation that the marketplace is now available.
Next, browse the available Skills:
/plugin list
You'll see a list of Skills available from the marketplace. Pick one that fits a task you do often. For this walkthrough, let's install a hypothetical meeting-notes-cleanup Skill (substitute whatever exists in the current marketplace):
/plugin install meeting-notes-cleanup
Claude Code or Cowork downloads the Skill, places it in your personal Skills folder, and confirms installation. You may need to start a new chat for it to register.
Now test it. In a new chat, type:
/meeting-notes-cleanup[paste raw meeting notes from a recent meeting here]
Claude loads the Skill's instructions and produces a structured summary in the format the Skill specifies. You'll notice immediately that the output is cleaner and more consistent than what you'd get from a freeform prompt — that's the Skill's instructions doing their job.
Step 6 — Build Your Own First Skill From Scratch
Marketplaces are great, but the highest-leverage Skills are usually the ones tailored to your specific work. Building one is genuinely simple — it's writing a recipe in plain English. Let's walk through it.
Pick a task. The best candidates for a custom Skill: any prompt you've copy-pasted three or more times in the past month. Examples that work well:
Open your Skills folder. On Mac, it's at /Users/yourname/.claude/skills/ (you may need to make the .claude folder visible — press Cmd+Shift+. in Finder). On Windows, it's at C:\Users\yourname\.claude\skills\. Create a new folder for your Skill — for example, weekly-status-update. Inside that folder, create a file named exactly SKILL.md.
Fill in the template. Open SKILL.md in any text editor (TextEdit, Notepad, VS Code — anything that handles plain text). Paste this template and edit.
Save and test. Save the file. Open Claude Code or Cowork in a new chat. Type /weekly-status-update and watch your custom specialist run. If the output's off, edit the SKILL.md file (mostly the Instructions section) and try again — Skills update instantly without restart.
Iterate over a few uses. Your first version of a Skill is rarely perfect. After running it 5–10 times on real data, you'll notice patterns: maybe the bullets are too long, or the tone is too formal, or it's missing a section. Edit the Skill, refine, and the next run uses the new version. Most working Skills get 3–5 revisions in their first month.
Step 7 — Using Skills Day-to-Day
Once you have a few Skills installed, the daily workflow shifts. Instead of starting every task with "let me write a fresh prompt," you start with "which Skill fits this?" The change feels small at first but compounds quickly.
A few habits that make Skills genuinely useful:
Common Mistakes to Avoid
Three patterns that hold people back from getting full value out of Skills.
Mistake #1: Treating every prompt as Skill-worthy. Not every task you do is recurring enough to need a Skill. The "rule of three" works well — if you've used the same prompt three or more times in a month, build a Skill. If you've used it once or twice, keep it as a regular chat for now.
Mistake #2: Writing Skills with vague instructions. A Skill that says "respond professionally" gives Claude almost nothing to work with — the output will be the same as a generic prompt. Skills earn their value through specificity. The more concrete your instructions ("avoid these specific words," "always include this section," "match this tone using these examples"), the more reliable the output.
Mistake #3: Hoarding Skills you don't use. It's easy to install Skills out of curiosity ("oh, that looks neat") and never actually run them. Every unused Skill is just clutter. If you haven't used a Skill in 30 days, uninstall it. The marketplaces will still be there if you change your mind.
Going Further
Start a "Skills inbox" habit. Whenever you find yourself pasting the same prompt twice in one week, write it down. Once a month, look at the list — those are your candidates for new custom Skills. This habit alone tends to grow most people's personal Skills library to a useful 8–12 over a few months.
Try one paid Skill on Agensi. Most of the value in Skills comes from your own custom ones, but the paid marketplace has some genuinely sharp Skills that pay back their €5–15 cost in a single use. Domain-specialist Skills (legal contract review, AWS audit, SEO analysis) are the most common winners.
Read the next article in this series — Article 04 covers Perplexity Computer. Skills handle one-step specialist tasks; Perplexity Computer handles multi-step research that crosses many websites. Together they cover most of what non-developers need from agents in 2026.
Key Takeaways
Here's what you learned in this guide:
The first Skill you install feels small. The fifth one feels like cheating. By the time you have 10 well-tuned Skills available as slash commands, your daily Claude experience is fundamentally different — every recurring task gets a specialist, your "good prompts" Notion page becomes obsolete, and you stop second-guessing whether a task is worth doing at all.