list_sandboxes

THE RISK

Low Risk

Why list_sandboxes needs a policy

This is a pure information retrieval tool. It queries the state of existing sandboxes and packages but does not create, modify, execute code, delete, or perform any operations with external effects. The action is inherently safe and produces no side effects beyond returning status data.

From the tool's definition Tool description states 'Lists all existing Python sandboxes and their status' — a read-only query operation with no side effects. It retrieves and returns information about sandboxes and installed packages without modifying, executing, or deleting anything.

Documented attack patterns abuse exactly the kind of access list_sandboxes gives an agent:

POLICY

How to control list_sandboxes

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Sandbox, and nothing reaches the server without passing your rules. This is the rule we recommend for list_sandboxes:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_sandboxes": {}
  }
}

list_sandboxes is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register MCP Sandbox — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More MCP Sandbox tools

Execute execute_python_code Executes Python code in a sandbox and returns results with links to generated files. Param Execute execute_terminal_command Executes a terminal command in the specified sandbox. Parameters: sandbox_id (string), com Execute install_package_in_sandbox Installs a Python package in the specified sandbox. Parameters: sandbox_id (string), packa Write create_sandbox Creates a new Python sandbox and returns its ID for subsequent operations. Optional parame Write upload_file_to_sandbox Uploads a local file to the specified sandbox. Parameters: sandbox_id (string), local_file Read check_package_installation_status Checks the installation status of a package in a sandbox. Parameters: sandbox_id (string),

All 7 MCP Sandbox tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about list_sandboxes

What does the list_sandboxes tool do? +

Lists all existing Python sandboxes and their status. Each item also includes installed Python packages. It is categorised as a Read tool in the MCP Sandbox MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_sandboxes? +

Register the MCP Sandbox MCP server in PolicyLayer and add a rule for list_sandboxes: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches MCP Sandbox. Nothing to install.

What risk level is list_sandboxes? +

list_sandboxes is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_sandboxes? +

Yes. Add a rate_limit block to the list_sandboxes rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block list_sandboxes completely? +

Set action: deny in the PolicyLayer policy for list_sandboxes. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides list_sandboxes? +

list_sandboxes is provided by the MCP Sandbox MCP server (johanli233/mcp-sandbox). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP Sandbox tool call.

Start from MCP Sandbox, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →