flow-nexus-sandbox

A tool for creating and managing isolated code-running environments called sandboxes. It provides ready-made Node.js, Python, React, Next.js, vanilla JavaScript, and basic environments, and supports running code, moving files, checking status, stopping, and deleting them.

In plain words
What is it for?
Use it to test JavaScript or other supported code, run React or Next.js projects, call APIs from an isolated environment, upload data files, and manage running sandboxes.
Why use it?
It lets code run separately from the main project, which helps limit the impact of experiments and gives tasks a clean environment. Sandboxes can also receive environment variables and have a time limit.

Command for Claude Code

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.

agentmods
npx agentmods add commands/ruvnet/sublinear-time-solver/sandbox
Clone the repo
git clone --depth 1 https://github.com/ruvnet/sublinear-time-solver

Made for: Claude Code.

Per session 15 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 487 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00015 $0.00487
Opus 5 $0.00008 $0.00244
Sonnet 5 $0.00003 $0.00097
Haiku 4.5 $0.00002 $0.00049

Measured 3d ago against content hash 6940ff3b42fa, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

flow-nexus-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 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.

Origin

Copies of this mod

3 near-identical copies found in the catalogue:

.claude/commands/flow-nexus/sandbox.md · 83 lines

What it actually says

Flow Nexus Sandboxes

Deploy and manage isolated execution environments.

Create Sandbox

mcp__flow-nexus__sandbox_create({
  template: "node", // node, python, react, nextjs, vanilla, base
  name: "my-sandbox",
  env_vars: {
    API_KEY: "your_api_key",
    NODE_ENV: "development"
  },
  timeout: 3600 // seconds
})

Execute Code

mcp__flow-nexus__sandbox_execute({
  sandbox_id: "sandbox_id",
  code: `
    console.log('Hello from sandbox!');
    const result = await fetch('https://api.example.com');
    return result.json();
  `,
  language: "javascript",
  capture_output: true
})

Manage Sandboxes

// List all sandboxes
mcp__flow-nexus__sandbox_list({ status: "running" })

// Get status
mcp__flow-nexus__sandbox_status({ sandbox_id: "id" })

// Upload file
mcp__flow-nexus__sandbox_upload({
  sandbox_id: "id",
  file_path: "/app/data.json",
  content: JSON.stringify(data)
})

// Stop sandbox
mcp__flow-nexus__sandbox_stop({ sandbox_id: "id" })

// Delete sandbox
mcp__flow-nexus__sandbox_delete({ sandbox_id: "id" })

Templates

  • node: Node.js environment
  • python: Python 3.x environment
  • react: React development setup
  • nextjs: Next.js full-stack
  • vanilla: Basic HTML/CSS/JS
  • base: Minimal Linux environment

Common Patterns

// API development sandbox
mcp__flow-nexus__sandbox_create({
  template: "node",
  name: "api-dev",
  install_packages: ["express", "cors", "dotenv"],
  startup_script: "npm run dev"
})

// ML sandbox
mcp__flow-nexus__sandbox_create({
  template: "python",
  name: "ml-training",
  install_packages: ["numpy", "pandas", "scikit-learn"]
})
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 First seen · 83 lines · 15 tokens per session scan A 6940ff3b42fa

Subscribe to this mod's changes

flow-nexus-sandbox is a command published in the GitHub repository ruvnet/sublinear-time-solver (89 stars, last pushed 1mo ago), licensed MIT. It adds 15 tokens to every session and 487 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.