---
title: "The sandbox skill"
description: "The arete-sandbox agent skill teaches an agent the sandbox loop, refusals and retries. a4 init installs the skills your account can use."
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---

> For the complete documentation index optimized for AI agents, see [llms.txt](https://docs.arete.run/llms.txt) or [llms-full.txt](https://docs.arete.run/llms-full.txt). A markdown version of this page is available at [/sandboxes/skill.md](https://docs.arete.run/sandboxes/skill.md) or by sending `Accept: text/markdown`.
A skill is a set of instructions an agent loads when a task calls for it.
`arete-sandbox` teaches an agent to act from a sandbox:

- find its sandbox with `sandbox_list`, and choose one with `sandbox_select`
  when several are granted;
- read `sandbox_status` and `sandbox_rules` before acting;
- preview every action with `sandbox_preview`, then run it with
  `sandbox_invoke`;
- pass amounts as decimal strings in the smallest unit;
- follow a refusal's `hint`, and never route around a rule;
- after a timeout, look the action up with `sandbox_action` before retrying;
- answer "what did you do" from `sandbox_history`; and
- never ask for a private key or the owner's API key.

The agent loads it when the `sandbox_*` tools are listed, or you ask it to
trade, swap, withdraw, read through a sandbox or explain a refusal.

## Install

`a4 init` installs it, with the MCP configuration, for the agent running the
command and any agent configured in the project:

```bash
a4 init -y
```

To install the skill on its own:

```bash
npx skills add AreteA4/skills --skill arete-sandbox
npx skills add AreteA4/skills --skill arete-sandbox --agent claude-code
```

## Skills follow your account

`a4 init` installs only the skills your account's command groups cover, the
same groups that decide which `a4` commands are listed. An agent account with
sandbox access gets:

| Skill            | Group     | Use                                                   |
| ---------------- | --------- | ----------------------------------------------------- |
| `arete-sandbox`  | sandboxes | Acting from a sandbox                                 |
| `arete`          | registry  | Discovery, exact descriptors and project dependencies |
| `arete-programs` | registry  | Program accounts, PDAs and transactions               |

Accounts in the [private beta](/private-beta/) also get the skills for
streams, stacks, protocols and dev environments; see
[Agent skills](/agent-skills/overview/). When the API can't be reached, or
`a4 init` runs without an account key, it installs every skill.

Run `a4 init -y` again after your account gains access to more, and
`a4 doctor` reports any skill your account should have that is missing.