Skills

Job Training for Claude

Think of the difference between a new hire and a trained employee. A new hire needs step-by-step instructions every time: "First open the spreadsheet, then filter by this column, then copy the results, then paste them here." A trained employee just needs: "Run the weekly report."

Skills are how you train Claude.

A skill is a text file that defines a specific workflow. When you invoke it, Claude follows the instructions in order, with the right tools, applying the right conventions. You define it once and use it forever.

MCP teaches Claude how to use a tool (like teaching someone to operate a cash register). A skill teaches Claude how to do a workflow (like teaching someone the entire opening procedure for the store: turn on lights, count the drawer, unlock the doors, in that order).

How Skills Work

Skills live as text files, either in your project directory or in your global Claude configuration. The harness (Lesson 9) loads them at session start, just like it loads CLAUDE.md and MCP servers.

You invoke a skill with a slash command. Type /deploy and the deploy skill runs. Type /catch-up and the catch-up skill gathers your morning context. The skill name matches the file name.

Inside, a skill is just a prompt, but a very specific, well-tested prompt that encodes a workflow. It might say: "First check for uncommitted changes. Then run the test suite. If tests pass, build the container. If the build succeeds, push to the staging environment. Report the result." Claude follows those steps, using its built-in tools and MCP connections to execute each one.

Building Your Own Skills

Start with something you explain to Claude repeatedly. If you find yourself typing the same kind of instruction across multiple sessions ("check my tickets, summarize what is open, tell me what to work on today"), that is a skill waiting to be written.

Ask Claude Code to help: "Create a skill called 'standup' that checks my project board, summarizes open items, and suggests what to work on today." Claude will generate the skill file, place it in the right location, and you can invoke it with /standup from then on.

The best skills are specific and opinionated. They do not try to handle every edge case. They encode the way YOU do something, so Claude does it the same way every time.

Skills vs. CLAUDE.md vs. MCP

These three things work together but serve different purposes:

CLAUDE.md is passive context. Claude reads it at the start of every session to understand your project. It does not tell Claude to do anything; it just provides background knowledge.

MCP gives Claude access to external tools. It adds new capabilities (query a CRM, send an email, create a ticket) but does not define when or how to use them.

Skills are active workflows. They tell Claude what to do, in what order, using which tools. A skill might say "use the CRM MCP to pull open deals, then use the email MCP to send a summary." It orchestrates the other pieces.

Think of it this way: CLAUDE.md is the employee handbook, MCP is the set of tools in the workshop, and skills are the standard operating procedures that say which tools to use and when.

Further Reading