[ithkuil]

Can I organize skills hierarchically? If when many skills are defined, Claude Code loads all definitions into the prompt, potentially diluting its ability to identify relevant skills, I'd like a system where only broad skill group summaries load initially, with detailed descriptions loaded on-demand when Claude detects a matching skill group might be useful.

[simonw]

There's a mechanism for that built into skills already: a skill folder can also include additional reference markdown files, and the skill can tell the coding agent to selectively read those extra files only when that information is needed on top of the skill.

There's an instruction about that in the Codex CLI skills prompt: https://simonwillison.net/2025/Dec/13/openai-codex-cli/

  If SKILL.md points to extra folders such as references/, load only the specific files needed for the request; don't bulk-load everything.

[ithkuil]

yes but those are not quite new skills right?

can those markdown in the references also in turn tell the model to lazily load more references only if the model deems they are useful?

[simonw]

Yes, using regular English prompting:

  If you need to write tests that mock
  an HTTP endpoint, also go ahead and
  read the pytest-mock-httpx.md file