Nimbus: Command for Claude Code

.claude/commands/nimbus-sandbox-and-extensions.md

nimbus-sandbox-and-extensions is a command for Claude Code from nimbus-agent/Nimbus. It costs 416 tokens per session (7,715 once invoked), scanned A, original, AGPL-3.0.

A command set for running third-party code in an operating-system sandbox, which restricts what that code can access. It covers sandbox setup across Linux, macOS, and Windows and limits the environment given to child processes.

In plain words
What is it for?
Use it when launching untrusted extensions or third-party servers, applying access policies, setting their working directory, and providing a restricted environment to child processes.
Why use it?
It reduces the risk that an extension or other external process can affect the rest of the system. It also keeps the rules for starting those processes consistent across operating systems.

Command for Claude Code

Written for Claude Code: installed under .claude/.

This is nimbus-agent/Nimbus's own configuration. It tells Claude Code how to work on Nimbus itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything Nimbus configures →

Reuse

Borrowing it

Nothing to install: this file belongs to nimbus-agent/Nimbus. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/nimbus-agent/Nimbus/main/.claude/commands/nimbus-sandbox-and-extensions.md
Clone the repo
git clone --depth 1 https://github.com/nimbus-agent/Nimbus

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.

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README.md
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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 nimbus-sandbox-and-extensions

Your own site · 80×15
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Per session 416 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 7,715 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 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 $0.00416 $0.07715
Opus 5.5 $0.00166 $0.03086
Sonnet 5.5 $0.00083 $0.01543
Haiku 4.5 $0.00042 $0.00771

Measured 3d ago against content hash db209e969df2, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

nimbus-sandbox-and-extensions 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 3d 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.

.claude/commands/nimbus-sandbox-and-extensions.md · 208 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, 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. 3d ago Changed · +9 lines db209e969df2
  2. 6d ago Changed · +1 lines 18849e6552f0
  3. 8d ago First seen · 198 lines · 416 tokens per session scan A b3acd1b29462

Subscribe to this mod's changes

nimbus-sandbox-and-extensions is a command published in the GitHub repository nimbus-agent/Nimbus (7 stars, last pushed yesterday), licensed AGPL-3.0. It adds 416 tokens to every session and 7,715 once invoked, about $0.0017 per session on Opus 5.5. 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 2026-10-19.