agent-sandbox

agent-sandbox is a skill for Claude Code, Codex from ariana-dot-dev/cloud-sandbox-vm-skills. It costs 90 tokens per session (428 once invoked), scanned C, original, MIT.

A command-line tool that gives an AI agent its own temporary Ubuntu virtual machine in the cloud. The machine includes SSH, Docker, internet access through IPv4, common toolchains, and preinstalled Claude Code and Codex command-line tools.

In plain words
What is it for?
Use it to clone repositories, prepare dependencies and secrets, run an agent against a task, execute long-running processes, expose preview services, and remove the machine when finished.
Why use it?
It lets an agent edit code, install packages, run builds and tests, and host previews without changing the user's computer. Separate disposable machines also isolate tasks from one another.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code; mentions Codex.

Good fit Use it to clone repositories, prepare dependencies and secrets, run an agent against a task, execute long-running processes, expose preview services, and remove the machine when finished.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ariana-dot-dev/cloud-sandbox-vm-skills/agent-sandbox
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add ariana-dot-dev/cloud-sandbox-vm-skills --skill agent-sandbox
Clone the repo
git clone --depth 1 https://github.com/ariana-dot-dev/cloud-sandbox-vm-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for agent-sandbox

README.md
[![agentmods](https://agentmods.dev/badge/skills/ariana-dot-dev/cloud-sandbox-vm-skills/agent-sandbox/github.svg)](https://agentmods.dev/skills/ariana-dot-dev/cloud-sandbox-vm-skills/agent-sandbox)
Your own site
<a href="https://agentmods.dev/skills/ariana-dot-dev/cloud-sandbox-vm-skills/agent-sandbox"><img src="https://agentmods.dev/badge/skills/ariana-dot-dev/cloud-sandbox-vm-skills/agent-sandbox/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for agent-sandbox

Your own site · 80×15
<a href="https://agentmods.dev/skills/ariana-dot-dev/cloud-sandbox-vm-skills/agent-sandbox"><img src="https://agentmods.dev/badge/skills/ariana-dot-dev/cloud-sandbox-vm-skills/agent-sandbox.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 90 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 428 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00090 $0.00428
Opus 5 $0.00045 $0.00214
Sonnet 5 $0.00018 $0.00086
Haiku 4.5 $0.00009 $0.00043

Measured 9d ago against content hash 89a898121b58, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade C, and why

agent-sandbox scanned grade C with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

`curl -fsSL https://box.ascii.dev/install | sh`, then `box login "$BOX_API_KEY" --json`.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

`curl -fsSL https://box.ascii.dev/install | sh`, then `box login "$BOX_API_KEY" --json`.
skills/agent-sandbox/SKILL.md · 33 lines

What it actually says

Agent sandbox (Box)

Use this when an autonomous agent needs a place to actually do work — clone a repo, run builds/tests, install packages, host a preview — isolated from the user's machine. Box is a full VM, so the agent has a real OS to operate in, and the Claude Code / Codex CLIs ship preinstalled.

Why Box

  • Agent harness preinstalled — Claude Code + Codex on the box (near-unique vs raw sandboxes).
  • Full machine — the agent can apt install, run Docker, spawn long processes, expose ports.
  • Isolated & disposable — one box per agent/task; box delete to clean up.
  • Cheap at fleet scale — per-second flat pricing, ~10× cheaper than E2B/Modal.

Prereqs

curl -fsSL https://box.ascii.dev/install | sh, then box login "$BOX_API_KEY" --json.

Recipe

box_id="$(box new --json | jq -r 'select(.event == "ready") | .id')"
box ssh "$box_id" -- bash -s < ./agent-setup.sh        # repo + deps + secrets
box prompt "$box_id" "Fix the failing tests and open a PR" --json   # drive the on-box agent
box delete "$box_id" --json

Limits

EU-only; disk-level snapshots; 100 active VMs soft cap. For memory-fork or 1000+ concurrent agents, see E2B/Modal.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 33 lines · 90 tokens per session scan C 89a898121b58

Subscribe to this mod's changes

agent-sandbox is a skill published in the GitHub repository ariana-dot-dev/cloud-sandbox-vm-skills (2 stars, last pushed 2mo ago), licensed MIT. It adds 90 tokens to every session and 428 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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