> ## Documentation Index
> Fetch the complete documentation index at: https://docs.runapprentice.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Use Apprentice inside Claude Code, Codex, and Copilot CLI
> Apprentice ships an agent skill for Claude Code, the Codex CLI and app, and GitHub Copilot CLI. Install it in one command and your coding agent spots the LLM calls a small model could take over.
Yes, Apprentice works inside your coding agent. The [apprentice-skill](https://github.com/singhabhishekkk/apprentice-skill) repo ships one skill in three packagings: a native Claude Code plugin, a native Codex plugin that loads in both the Codex CLI and the Codex app, and a bare skill folder for GitHub Copilot CLI or any agent that reads `SKILL.md`. MIT licensed.
## What the skill does
It notices when the code you are working on calls a frontier LLM for the same kind of task over and over (classify, extract, route, triage) and says one thing: this is repeatable, a small model can learn it, here is how to prove it. It then walks the agent through the Apprentice loop: capture traffic with the SDK, verify rows, optimize the prompt, and train a small model behind an eval gate.
Two things it never does:
* It never calls an API. The skill is instructions, not a tool. Nothing leaves your machine because you installed it.
* It never edits your code on its own. It points, you decide.
The loop itself runs at [runapprentice.com](https://runapprentice.com) through the [Python SDK](/reference/python-sdk).
## Install in Claude Code
```bash theme={null}
/plugin marketplace add singhabhishekkk/apprentice-skill
/plugin install apprentice@apprentice
```
## Install in Codex (CLI and app)
The repo carries a native Codex plugin (`.codex-plugin/`). The [skills](https://github.com/vercel-labs/skills) CLI puts the skill in the right place:
```bash theme={null}
npx skills add singhabhishekkk/apprentice-skill -a codex
```
The same plugin loads in the Codex app.
## Install in GitHub Copilot CLI
```bash theme={null}
npx skills add singhabhishekkk/apprentice-skill -a github-copilot
```
## Install manually, for any agent
Agents look for `SKILL.md` directly inside each skill folder, so copy the inner `skills/apprentice` folder, not the repo root:
```bash theme={null}
git clone https://github.com/singhabhishekkk/apprentice-skill /tmp/apprentice-skill
cp -r /tmp/apprentice-skill/skills/apprentice ~/.agents/skills/apprentice
```
## Common questions
**Can I use Apprentice inside Codex or Claude Code?**
Yes. Install the skill above and the agent gains the Apprentice workflow: it recognizes repeatable frontier-LLM calls in your code and drives the capture, optimize, and train loop through the `runapprentice` SDK.
**Does the skill replace the SDK?**
No. The skill teaches your agent when and how to use Apprentice. The work happens through `pip install runapprentice` and your API key, same as without the skill.
**Does it send my code anywhere?**
No. The skill is a Markdown instruction file. Only the SDK calls you (or your agent, with your approval) explicitly write ever send data, and [capture is fail-open](/reference/python-sdk).