3 ms·

Yes, it happens on startup of a fresh Claude Code / Codex CLI session. They effectively get pasted into the system prompt. Reading a few dozen files takes on t

by simonw 11mo ago

Yes, it happens on startup of a fresh Claude Code / Codex CLI session. They effectively get pasted into the system prompt. Reading a few dozen files takes on the order of a few ms. They add enough tokens per skill to fit the metadata description, so probably less than 100 for each skill.

raybb 11mo ago
So when it says: > The body can contain any Markdown; it is not injected into context. It just means it's not injected into the context until the skill is used or it's never injected into the context? https://github.com/openai/codex/blob/main/docs/skills.md https://github.com/openai/codex/blob/main/docs/skills.md
- simonw 11mo ago
  Yeah, that means that the body of that file will not be injected into the context on startup. I had thought that once the skill is selected the whole file would be read, but it looks like that's not the case: https://github.com/openai/codex/blob/ad7b9d63c326d5c92049abd16f9f5fb64a573a69/codex-rs/core/src/skills/render.rs#L25 https://github.com/openai/codex/blob/ad7b9d63c326d5c92049abd... 1) After deciding to use a skill, open its `SKILL.md`. Read only enough to follow the workflow. So you could have a skill file that's thousands of lines long but if the first part of the file provides an outline Codex may stop reading at that point. Maybe you could have a skill that says "see migrations section further down if you need to alter the database table schema" or similar.
  - wahnfrieden 11mo ago
    Knowing Codex, I wonder if it might just search for text in the skill file and read around matches, instead of always reading a bit from the top first.
  - debugnik 11mo ago
    Can models actually stream the file in as they see fit, or is "read only enough" just an attention trick? I suspect the latter.
    - true2octave 11mo ago
      Depends the agent, they can read in chunks (i.e.: 500 lines at a time)

by simonw 11mo ago

raybb 11mo ago

So when it says: > The body can contain any Markdown; it is not injected into context. It just means it's not injected into the context until the skill is used or it's never injected into the context? https://github.com/openai/codex/blob/main/docs/skills.md https://github.com/openai/codex/blob/main/docs/skills.md

simonw 11mo ago
Yeah, that means that the body of that file will not be injected into the context on startup. I had thought that once the skill is selected the whole file would be read, but it looks like that's not the case: https://github.com/openai/codex/blob/ad7b9d63c326d5c92049abd16f9f5fb64a573a69/codex-rs/core/src/skills/render.rs#L25 https://github.com/openai/codex/blob/ad7b9d63c326d5c92049abd... 1) After deciding to use a skill, open its `SKILL.md`. Read only enough to follow the workflow. So you could have a skill file that's thousands of lines long but if the first part of the file provides an outline Codex may stop reading at that point. Maybe you could have a skill that says "see migrations section further down if you need to alter the database table schema" or similar.
- wahnfrieden 11mo ago
  Knowing Codex, I wonder if it might just search for text in the skill file and read around matches, instead of always reading a bit from the top first.
- debugnik 11mo ago
  Can models actually stream the file in as they see fit, or is "read only enough" just an attention trick? I suspect the latter.
  - true2octave 11mo ago
    Depends the agent, they can read in chunks (i.e.: 500 lines at a time)