[netcraft]

apparently I missed Simon Willison's article, this at least somewhat explains them: https://simonwillison.net/2025/Oct/16/claude-skills/

So if youre building your own agent, this would be a directory of markdown documents with headers that you tell the agent to scan so that its aware of them, and then if it thinks they could be useful it can choose to read all the instructions into its context? Is it any more than that?

I guess I dont understand how this isnt just RAG with an index you make the agent aware of?

[brabel]

It also looks a lot like a tool that has a description mentioning it has a more detailed MD file the LLM can read for instructions on complex workflows, doesn’t it? MCP has the concept of resources for this sort of thing. I don’t see any difference between calling a tool and calling a CLI otherwise.

[nostrebored]

I mean it is technically RAG as the LLM is deciding to retrieve a document. But it’s very constrained.

The skills that I use all direct a next action and how to do it. Most of them instruct to use Tasks to isolate context. Some of them provide abstraction specific context (when working with framework code, find all consumers before making changes. add integration tests for the desired state if it’s missing, then run tests to see…) and others just inject only the correct company specific approach to solving only this problem into Task context.

They are composable and you can build the logic table of when an instance is “skilled” enough. I found them worse than hooks with subagents when I started, but now I see them as the coolest thing in Claude code.

The last benefit is nobody on your team even had to know they exist. You can just have them as part of onboarding and everyone can take advantage of what you’ve learned even when working on greenfield projects that don’t have a CLAUDE.md.