sandbox-unblock

sandbox-unblock is a skill for Claude Code from FlorianBruniaux/claude-code-ultimate-guide. It costs 65 tokens per session (2,189 once invoked), scanned A, original, CC-BY-SA-4.0.

A diagnostic checklist for investigating apparent sandbox restrictions before reporting a problem.

In plain words
What is it for?
Use it to check eight possible causes, then produce a report that a configuration owner can act on.
Why use it?
It helps distinguish genuine configuration limits from false reports caused by other issues.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is ./node_modules/.bin/<binary> --version.

Good fit Use it to check eight possible causes, then produce a report that a configuration owner can act on.

Compare 6 skills from other repositories ↓
About the project

Claude Code Ultimate Guide is a structured documentation project for learning how to build, operate, and govern coding agents with Claude Code. It serves developers and teams through guidance on agentic workflows, hooks, skills, MCP servers, security, and adoption. The catalogue entries are reusable skills, commands, agents, hooks, instructions, settings, and a plugin drawn from the guide's workflow materials.

FlorianBruniaux/claude-code-ultimate-guide · 5,918 stars · on GitHub · cc.bruniaux.com

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/FlorianBruniaux/claude-code-ultimate-guide
agentmods
npx agentmods add skills/florianbruniaux/claude-code-ultimate-guide/sandbox-unblock

Made for: Claude Code.

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-unblock

README.md
[![agentmods](https://agentmods.dev/badge/skills/florianbruniaux/claude-code-ultimate-guide/sandbox-unblock/github.svg)](https://agentmods.dev/skills/florianbruniaux/claude-code-ultimate-guide/sandbox-unblock)
Your own site
<a href="https://agentmods.dev/skills/florianbruniaux/claude-code-ultimate-guide/sandbox-unblock"><img src="https://agentmods.dev/badge/skills/florianbruniaux/claude-code-ultimate-guide/sandbox-unblock/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-unblock

Your own site · 80×15
<a href="https://agentmods.dev/skills/florianbruniaux/claude-code-ultimate-guide/sandbox-unblock"><img src="https://agentmods.dev/badge/skills/florianbruniaux/claude-code-ultimate-guide/sandbox-unblock.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,189 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: 2 findings, up to high

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 →

  • high Privilege Escalation · line 171
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 174
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
How audits are shown
Origin unknown 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 $0.00065 $0.02189
Opus 5 $0.00032 $0.01094
Sonnet 5 $0.00013 $0.00438
Haiku 4.5 $0.00006 $0.00219

Measured 5d ago against content hash 4640aae48f94, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

sandbox-unblock 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 5d 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.

examples/skills/sandbox-unblock/SKILL.md · 209 lines

The source is not reproduced here

Licensed CC-BY-SA-4.0

The repository is licensed CC-BY-SA-4.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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. 5d ago First seen · 209 lines · 65 tokens per session scan A 4640aae48f94

Subscribe to this mod's changes

sandbox-unblock is a skill published in the GitHub repository FlorianBruniaux/claude-code-ultimate-guide (5,918 stars, last pushed yesterday), licensed CC-BY-SA-4.0. It adds 65 tokens to every session and 2,189 once invoked, about $0.0003 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 2026-09-03.

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