High Risk →

sandbox_create

Create and boot a persistent named sandbox with full configuration.

How to control sandbox_create ↓

What sandbox_create does on Microsandbox

AI agents invoke sandbox_create to trigger actions in Microsandbox. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

High Risk

Why sandbox_create needs a policy

Creating and booting a sandbox involves executing system-level operations to instantiate a new isolated environment. While it doesn't delete data (not Destructive) or move money (not Financial), it triggers external infrastructure operations — spinning up compute resources that persist. This is more than a Write (data mutation) because it launches an active execution environment.

From the tool's definition 'Create and boot a persistent named sandbox with full configuration' — spawns a new sandbox environment (an external resource/process)

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

How to control sandbox_create

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

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "sandbox_create": {
      "limits": [
        {
          "counter": "sandbox_create_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

sandbox_create stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

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

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Questions about sandbox_create

What does the sandbox_create tool do? +

Create and boot a persistent named sandbox with full configuration. It is categorised as a Execute tool in the Microsandbox MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on sandbox_create? +

Register the Microsandbox MCP server in PolicyLayer and add a rule for sandbox_create: 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 Microsandbox. Nothing to install.

What risk level is sandbox_create? +

sandbox_create is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit sandbox_create? +

Yes. Add a rate_limit block to the sandbox_create 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 sandbox_create completely? +

Set action: deny in the PolicyLayer policy for sandbox_create. 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 sandbox_create? +

sandbox_create is provided by the Microsandbox MCP server (superradcompany/microsandbox-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Microsandbox tool call.

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

Free to start. No card required.

19 Microsandbox tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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