Sandbox Next skill for Claude Code: Cloudflare Sandbox on the 1.0 preview

Cloudflare's skill that makes Claude build Sandbox apps on the 1.0 preview SDK (@next), for Workers developers starting new projects.

Installs: 73.2K; on skills.sh
Stars: 3.2K; on GitHub
Files: 3; besides SKILL.md
Updated: Oct 2026; last repo commit

Claude checks that your app is on @cloudflare/sandbox@next and then follows the preview rules. exec takes an argv list and returns a handle as soon as the process starts, so Claude reads results with output(), logs(), waitForExit(), waitForPort() or kill(). There is no implicit shell and no cd carried between calls.

The SKILL.md says new projects should use this line and that APIs change, so Claude should trust the installed @next types over memory. It bundles three reference files and no scripts.

Good for

Developers starting a new Cloudflare Sandbox project
Teams already on @cloudflare/sandbox@next
Developers building agent harnesses or browser terminals on Sandbox

Install sandbox-next

Claude Code

Copy this prompt.

Install the sandbox-next skill in Claude Code. Run this command:

/plugin marketplace add cloudflare/skills
/plugin install cloudflare@cloudflare

Then check that it loaded and tell me how to use it.

2
Paste it into Claude Code. It shows the change and asks before running it.

The three Sandbox skills hand over to each other: each one stops and loads another when it finds the wrong package line, so install all three. The plugin installs every Cloudflare skill plus Cloudflare's main remote MCP server (README). Pick one route, not both. Start a new session afterwards.

From the project README. Source.

What's in the skill

When it loads

Build or maintain Cloudflare Sandbox apps on @cloudflare/sandbox@next (SDK 1.0 preview). Use sandbox-migrate-to-next when porting a stable app.

Sections in SKILL.md

1. Gate — confirm the package line
2. Contract — non-negotiables
3. Retrieve — open the doc for the task
4. Before you ship
Skill feedback

Key facts

Author: Cloudflare
Repository: cloudflare/skills
Installs on skills.sh: 73,178 (2 Nov 2026)
GitHub stars (repo): 3,244 (2 Nov 2026)
License: Apache-2.0
Last commit (repo): 31 Oct 2026
What installs: SKILL.md plus 3 files in references/ (api-quick-ref.md, examples.md, skill-feedback.md); bundles no scripts
Works in: Claude Code, Codex, Cursor and VS Code / GitHub Copilot (install routes listed in the README)
skills.sh audits: Gen Agent Trust Hub pass, Socket pass, Snyk pass

What it includes

Needs @cloudflare/sandbox@next and a matching image
Claude checks the npm dependency and container image. On the default package it stops and loads sandbox-stable; to port, it loads sandbox-migrate-to-next.
Read · Gate: confirm the package line
exec(argv) returns a process handle, not a result
Claude uses handle methods to collect output, wait for exit, port or a log line, or kill the process. Each launch is independent, and handles have no stdin.
Try: “Start my dev server in the sandbox and wait for port 3000.”
Read · Contract: preview rules
A table of preview docs pages for each task
Claude opens the right page for processes, lifecycle, environment, terminals, interpreter, extensions and errors before it implements.
Network · Retrieve: open the doc first
Task-to-docs map for the preview APIs
A bundled table that maps tasks (processes, lifecycle, sleep options, terminals, interpreter, environment, errors) to the Cloudflare docs page Claude should fetch first.
Read · references/api-quick-ref.md
Index of example apps on the next branch
Points to Cloudflare's example apps such as minimal, code-interpreter, collaborative-terminal and authentication.
Read · references/examples.md
Lockfile and Dockerfile on the same @next line, typecheck, no live secrets
A checklist for the end of the job.
Read · Before you ship
Draft a public GitHub issue about the skill, only with your approval
If you say the skill gave wrong or outdated advice, Claude can draft an issue for you to review before anything is posted.
Network · Skill feedback

From the official docs

Permissions

Low risk

The skill is guidance and reference files. The outward action it describes is a feedback issue that Claude posts publicly after you approve its text.

What it can do

Read your data
Create and change things
Delete things
Read-only mode

Watch out for

Feedback can open a public GitHub issue
The skill's feedback steps ask permission, show you the exact title and body, and post to cloudflare/skills only after you say yes. Keep secrets, account IDs and private code out of that text. github.com

Security advisories

No published security advisories as of Nov 2, 2026.

Technical details

Turning on read-only	The skill defines no read-only switch. It is instructions plus reference files.
Talks to	Cloudflare docs pages at developers.cloudflare.com. GitHub, only if you approve a feedback issue
Scopes	Claude reads your dependencies and container image setting Claude fetches Cloudflare docs pages

Questions

What does the Sandbox Next skill do?

It makes Claude write Cloudflare Sandbox code for the 1.0 preview package, @cloudflare/sandbox@next. It teaches the new process-handle model and sends Claude to Cloudflare's docs for details.

Sandbox Next vs sandbox-stable?

Use sandbox-next for apps on @cloudflare/sandbox@next; the skill recommends it for new projects. Use sandbox-stable for apps on the default package. The two have different exec behaviour, so each skill tells Claude to stop and switch if it finds the other line.

How do I install it?

Use the install box at the top of this page. The README also documents a Claude Code plugin (/plugin marketplace add cloudflare/skills, then /plugin install cloudflare@cloudflare) that installs all of Cloudflare's skills together with Cloudflare's main MCP server. Start a new session afterwards.

Does it work in Codex, Cursor or Copilot?

Yes. The README lists install routes for Codex, VS Code with GitHub Copilot, Cursor and the skills CLI. Skills load on their own when your request matches. The README does not describe a Claude app install.

Does it need an API key?

The SKILL.md names no API key. It says to put only non-secret config in sandbox environment variables and keep live credentials in the Worker.

Is it safe to install?

It is low risk. It bundles no scripts, only a rulebook, two reference files and a feedback instruction. Claude can open a public GitHub issue about the skill only after you approve the exact text. Review any code it writes before you deploy.

Information

updated Nov 2, 2026

Repository: cloudflare/skills
Folder: skills/sandbox-next

cloudflare/skills skills.sh

Sources

Docs, issue trackers and discussions this page is built from.

Show all 6

cloudflare/skills README · github.com
skills CLI commands · github.com
sandbox-next SKILL.md · github.com
github.com · github.com
github.com · github.com
sandbox-next skill-feedback.md · github.com