Sandbox Isolation

Sandbox Isolation is a skill for Claude Code, Codex from TheArchitectit/agent-guardrails-template. It costs 19 tokens per session (617 once invoked), scanned A, original, BSD-3-Clause.

A Docker-based safety layer for running commands in an isolated environment with limits on network access, memory, CPU time, and duration.

In plain words
What is it for?
It helps run external scripts, user-provided code, unfamiliar project builds, and tests involving file deletion or database changes.
Why use it?
It reduces the risk that untrusted code, unfamiliar build commands, or destructive tests will damage files or use too many resources.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It helps run external scripts, user-provided code, unfamiliar project builds, and tests involving file deletion or database changes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/thearchitectit/agent-guardrails-template/sandbox-isolation
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 TheArchitectit/agent-guardrails-template --skill sandbox-isolation
Clone the repo
git clone --depth 1 https://github.com/TheArchitectit/agent-guardrails-template

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 Sandbox Isolation

README.md
[![agentmods](https://agentmods.dev/badge/skills/thearchitectit/agent-guardrails-template/sandbox-isolation/github.svg)](https://agentmods.dev/skills/thearchitectit/agent-guardrails-template/sandbox-isolation)
Your own site
<a href="https://agentmods.dev/skills/thearchitectit/agent-guardrails-template/sandbox-isolation"><img src="https://agentmods.dev/badge/skills/thearchitectit/agent-guardrails-template/sandbox-isolation/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 Sandbox Isolation

Your own site · 80×15
<a href="https://agentmods.dev/skills/thearchitectit/agent-guardrails-template/sandbox-isolation"><img src="https://agentmods.dev/badge/skills/thearchitectit/agent-guardrails-template/sandbox-isolation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 617 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 63
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
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 $0.00019 $0.00617
Opus 5 $0.00010 $0.00309
Sonnet 5 $0.00004 $0.00123
Haiku 4.5 $0.00002 $0.00062

Measured 10d ago against content hash 0315b4eceaa9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

Sandbox Isolation 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.

pi-extension/skills/sandbox-isolation/SKILL.md · 76 lines

How it starts

The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Sandbox Isolation

The pi-guardrails extension provides a Docker-based sandbox for executing commands that might be risky, untrusted, or potentially destructive. Sandboxed commands run with network isolation, memory limits, and CPU constraints.

When To Use the Sandbox

Use the sandbox when:

  • Running untrusted scripts from external sources
  • Executing build commands in unfamiliar projects
  • Testing destructive operations (file deletion, schema changes)
  • Running user-provided code snippets
  • Any command where the blast radius is unclear

Do NOT use the sandbox when:

  • Running standard git, read, or edit operations
  • The command is well-understood and low-risk
  • Docker is not available (check isAvailable first)

How It Works

The sandbox wraps docker run with:

  • No network access by default (--network=none)
  • Read-only mounts for source code inspection
  • Read-write mounts only for explicitly designated output paths
  • Memory limits (e.g., 512m) to prevent resource exhaustion
  • CPU limits (e.g., 1.0 core) to prevent CPU abuse
  • Timeouts (default 30s) to prevent hanging processes
  • Auto-cleanup (--rm) — containers are removed after execution

MCP Bridge

When connected, use guardrail_mcp with action sandbox_run:

action: sandbox_run
command: ["npm", "test"]
readOnlyMounts: ["/project/src"]
readWriteMounts: ["/project/test-results"]
networkAccess: false
memoryLimit: "512m"
timeout: 60000

The result includes exitCode, stdout, stderr, and timedOut fields.

Fallback When Docker Is Unavailable

If Docker is not installed or the daemon is not running, sandbox_run will return an error. In this case:

  1. Inform the user that sandbox is unavailable
  2. Ask for explicit permission before running the command outside the sandbox
  3. Proceed only after approval — do not assume consent

What To Do When a Sandbox Run Fails

  • Exit code != 0: The command itself failed — investigate stderr
  • timedOut: true: The command exceeded the timeout — increase or simplify the command
  • exit code null: Docker failed to start — check Docker availability

Read the full file on GitHub · 76 lines

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 · 76 lines · 19 tokens per session scan A 0315b4eceaa9

Subscribe to this mod's changes

Sandbox Isolation is a skill published in the GitHub repository TheArchitectit/agent-guardrails-template (79 stars, last pushed yesterday), licensed BSD-3-Clause. It adds 19 tokens to every session and 617 once invoked, about $0.0001 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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