app-platform-sandbox

app-platform-sandbox is a skill for Claude Code, Codex from digitalocean-labs/do-app-platform-skills. It costs 49 tokens per session (1,877 once invoked), scanned A, original, MIT.

A skill for creating isolated, temporary computer environments where an AI agent can install packages, run code, and repeat tests safely. These environments keep their state during a longer workflow.

In plain words
What is it for?
Use it for agent workflows, code execution, and testing that need isolation and may run for a long time.
Why use it?
It separates untrusted or experimental code from the main system and avoids setting up a local environment for each run.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Not installable: its command points at a path on the author’s own machine, so it runs nowhere else. The line is /home/sandbox/app.

Good fit Use it for agent workflows, code execution, and testing that need isolation and may run for a long time.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

There is no command for this one: it runs only inside a plugin, and the catalogue could not identify which plugin ships it. The source is linked below.

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 app-platform-sandbox

README.md
[![agentmods](https://agentmods.dev/badge/skills/digitalocean-labs/do-app-platform-skills/sandbox/github.svg)](https://agentmods.dev/skills/digitalocean-labs/do-app-platform-skills/sandbox)
Your own site
<a href="https://agentmods.dev/skills/digitalocean-labs/do-app-platform-skills/sandbox"><img src="https://agentmods.dev/badge/skills/digitalocean-labs/do-app-platform-skills/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 app-platform-sandbox

Your own site · 80×15
<a href="https://agentmods.dev/skills/digitalocean-labs/do-app-platform-skills/sandbox"><img src="https://agentmods.dev/badge/skills/digitalocean-labs/do-app-platform-skills/sandbox.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,877 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 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 $0.00049 $0.01877
Opus 5 $0.00024 $0.00938
Sonnet 5 $0.00010 $0.00375
Haiku 4.5 $0.00005 $0.00188

Measured 10d ago against content hash 107d711a7d25, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

app-platform-sandbox scanned grade A with 0 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 10d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/sandbox/SKILL.md · 240 lines

How it starts

The opening of the file, as written. The whole thing — 240 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Sandbox Skill

Isolated execution environments for AI agents and testing workflows.

Philosophy

Lambda/Functions: Fast cold start, 15-min limit, stateless, per-ms billing
App Platform Sandbox: 30s cold start (or instant with pool), unlimited duration, stateful, per-hour billing

Sweet spot: Long-running, stateful, iterative workflows where agents need to
install packages, run code, check results, modify, repeat.

Quick Decision

┌─────────────────────────────────────────────────────────────┐
│         Need isolated execution environment?                 │
└─────────────────────────────────────────────────────────────┘
                            │
              Is this for debugging an EXISTING app?
                            │
            ┌───────────────┴───────────────┐
            │                               │
           YES                              NO
            │                               │
            ▼                               ▼
   ┌─────────────────┐           ┌─────────────────┐
   │ troubleshooting │           │ Need real-time  │
   │ skill           │           │ streaming or    │
   │                 │           │ port exposure?  │
   │ Sandbox.get_    │           │                 │
   │ from_id()       │           └────────┬────────┘
   └─────────────────┘                    │
                          ┌───────────────┴───────────────┐
                          │                               │
                         YES                              NO
                          │                               │
                          ▼                               ▼
                 ┌─────────────────┐           ┌─────────────────┐
                 │ SERVICE MODE    │           │ Is low latency  │
                 │ exec_stream()   │           │ critical?       │
                 │ expose_port()   │           │                 │
                 └─────────────────┘           └────────┬────────┘
                                                        │
                                        ┌───────────────┴───────────────┐
                                        │                               │
                                       YES                              NO
                                        │                               │
                                        ▼                               ▼
                               ┌─────────────────┐           ┌─────────────────┐
                               │ HOT POOL        │           │ COLD SANDBOX    │
                               │ SandboxManager  │           │ Sandbox.create()│
                               │ ~50ms acquire   │           │ ~30s startup    │
                               └─────────────────┘           └─────────────────┘

Read the full file on GitHub · 240 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 10d ago First seen · 240 lines · 49 tokens per session scan A 107d711a7d25

Subscribe to this mod's changes

app-platform-sandbox is a skill published in the GitHub repository digitalocean-labs/do-app-platform-skills (36 stars, last pushed 3d ago), licensed MIT. It adds 49 tokens to every session and 1,877 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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