# Sandbox Stable

Build or maintain Cloudflare Sandbox apps on the stable @cloudflare/sandbox package.

- Repository: https://github.com/cloudflare/skills (3246 stars)
- Category: DevOps
- License: Apache-2.0
- Last updated: 2026-10-31
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add cloudflare/skills --skill sandbox-stable -g -a claude-code -y`
Codex: `npx skills add cloudflare/skills --skill sandbox-stable -g -a codex -y`
Cursor: `npx skills add cloudflare/skills --skill sandbox-stable -g -a cursor -y`
Gemini CLI: `npx skills add cloudflare/skills --skill sandbox-stable -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add cloudflare/skills`

## Description

Build or maintain Cloudflare Sandbox apps on the stable @cloudflare/sandbox package. Use sandbox-next for preview apps and sandbox-migrate-to-next for stable-to-preview migrations.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Sandbox SDK, stable package

Isolated Linux environments on [Cloudflare Containers](https://developers.cloudflare.com/containers/index.md), driven from Workers.

**Prefer the main Sandbox docs and installed stable types over memory.** This skill is a gate, a contract, and a retrieval map, not a full manual.

This line is the **current stable** default npm package. The main [Sandbox documentation](https://developers.cloudflare.com/sandbox/index.md) describes it. Existing apps can stay here and keep shipping.

We recommend **new projects** on `@cloudflare/sandbox@next` with **`sandbox-next`**. When you can, plan a move with **`sandbox-migrate-to-next`** so you are ready when 1.0 becomes the stable release. Do not force that port unless the user asks.

## 1. Gate, confirm the package line

Before writing code, inspect the app:

| Check | Must match |
| ----- | ---------- |
| npm dependency | Default `@cloudflare/sandbox` (**not** `@next` / preview tags) |
| Container image | Matching **stable** image (not `cloudflare/sandbox:next`) |

| If you find… | Action |
| ------------ | ------ |
| `@cloudflare/sandbox@next` or a `next` image | **Stop.** Load **`sandbox-next`**. |
| User wants to port to 1.0 / `@next` | **Stop.** Load **`sandbox-migrate-to-next`**. Do not half-apply preview APIs on a stable package. |
| Only cleaning deprecated stable APIs | Stay here; use the [2026 deprecation guide](https://developers.cloudflare.com/sandbox/sdk/migrate/index.md). That is **not** a move to `@next`. |

Never mix a stable Worker package with an `@next` container image (or the reverse).

Skills install: [Agent setup](https://developers.cloudflare.com/agent-setup/index.md) · [cloudflare/skills](https://github.com/cloudflare/skills)

## 2. Contract, non-negotiables

The rest: https://github.com/cloudflare/skills/blob/HEAD/skills/sandbox-stable/SKILL.md