Module 1 · Section 1 of 6

The word “agent” gets used for everything from a chatbot to a science fiction concept. That’s not useful. Let’s be specific.

A skill is a reusable instruction set. It’s a markdown file with a YAML header. It tells Claude how to approach a specific class of task — what to do, in what order, with what constraints. When you invoke it, those instructions load into context and shape the response.

An agent is a skill with tools. The instructions are the same kind of thing. But now Claude can act — read files, run bash commands, search the web, write to disk. The difference between a skill and an agent isn’t the instructions. It’s the reach.