If you use Claude frequently, you've probably already noticed that this Anthropic AI has many more layers than meet the eye. One of the most interesting—and one that many people still don't fully utilize—is Skills, a system of custom abilities that allows you to shape Claude to work exactly as you need it to. And the best part is that you can take them beyond the basics using external files in .md format. Here's everything you need to know.

What are Claude Skills and why should you use them?

Think of Skills as small "special modes" that you can activate in Claude to make it behave in a specific way depending on the task you need. They work similarly to ChatGPT's GPTs or Gemini's Gems, but with a key difference that significantly changes how you use them on a daily basis.

When you create a Skill within Claude's internal system, the AI ??stores it in its memory. So far, so good. The problem comes next: Claude automatically checks the names and descriptions of all the Skills you've created every time you type a prompt. If it detects that what you requested is similar to what one of them does, it launches it. Without you explicitly asking for it.

This might sound convenient, but when you start accumulating many Skills for different tasks, things get complicated. Claude might activate a skill you didn't intend to at that moment, simply because the prompt was similar to that Skill's context. It's like having an overly eager assistant who guesses what you want before you've even finished speaking.

The system's partial solution is to create very precise names and descriptions for each Skill, so that Claude understands exactly when to use it and when not to. If the names are too generic, the risk of unwanted activations increases considerably. But there's a much more elegant and effective solution: external Skills.

Why external Skills in .md files are the best option

The great advantage of external Skills is simple:They are only activated when you decide to attach them to a conversation. No automatic activations, no Claude using them when it's not appropriate. You have complete control.

How does this work in practice? Instead of storing the Skill within Claude's internal system, you save it in a Markdown (.md) text file on your device. When you want to use it, you simply attach that file to the conversation. When you don't attach it, Claude doesn't even know it exists.

This is especially useful if you work with multiple user profiles: one Skill for writing technical articles, another for summarizing documents, another for analyzing data, another for creating code… If they were all active at the same time within the system, the risk of interference would be high. With .md files, each one only comes into play when you decide.

Furthermore, these files are easy to share, edit, and organize into folders.

They are portable, which means you can move them from one device to another without having to reconfigure anything on the platform.

How to create your own .md file with a Skill step by step

Here comes the practical part. There are two ways to create an .md file with a Skill, and both are accessible even if you have no technical experience.

Option 1: Do it manually. Open any text editor (Notepad, TextEdit, VS Code, or whichever you prefer) and create a file with the following basic structure in Markdown format:

Save the file with the .md extension and you're done. It's that simple.

Option 2: Ask Claude to do it for you. This is undoubtedly the most efficient way and the one that gives the best results.

You just need to use a prompt like this:

“I want you to generate an .md file with a skill created for Claude. Here are the skill details: Name: [Name]. Description: [Description]. Instructions: [Detailed Skill Instructions]. Based on this information, I want you to generate the skill so that it works as well as possible with Claude, and then create an .md file for download.”

With this prompt, Claude optimizes the instructions so that the skill works as effectively as possible within its own system. When finished, it directly generates the .md file, ready for you to download and save wherever you want. You don't need to know anything about Markdown or programming to do this.

The key here is to be as specific as possible when describing the name and instructions. The more detailed you are, the better the final result will be.

A well-built skill can save you hours of work per week if you use it for repetitive tasks or those requiring a very particular style.

External skills in files .md are one of Claude's most powerful and least explored features, and mastering them can make a real difference to your daily productivity with this AI.