send-sandbox-email · Mcp Mailtrap MCP: Risk & Policy

WHAT IT DOES

What send-sandbox-email does on Mcp Mailtrap

AI agents use send-sandbox-email to create or update resources in Mcp Mailtrap — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mcp Mailtrap environment.

WHY IT NEEDS A POLICY

Why send-sandbox-email needs a policy

This tool creates email records in a sandbox environment. While it performs a write operation (creating email data), the sandbox mode and test inbox context limit the blast radius compared to actual email delivery. It's reversible (emails can be deleted), making it Write rather than Execute or Financial.

From the tool's definition Tool description states 'Send an email in sandbox mode to a test inbox' - this is a creation action that modifies data (creates email records) in a reversible manner.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send-sandbox-email Rate-limited

send-sandbox-email stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "send-sandbox-email": {
      "limits": [
        {
          "counter": "send-sandbox-email_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Mcp Mailtrap, so you can run agents against it safely.

FAQ

Questions about send-sandbox-email

What does the send-sandbox-email tool do? +

Send an email in sandbox mode to a test inbox without delivering to your recipients. It is categorised as a Write tool in the Mcp Mailtrap MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on send-sandbox-email? +

Register the Mcp Mailtrap MCP server in PolicyLayer and add a rule for send-sandbox-email: 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 Mailtrap. Nothing to install.

What risk level is send-sandbox-email? +

send-sandbox-email is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit send-sandbox-email? +

Yes. Add a rate_limit block to the send-sandbox-email 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 send-sandbox-email completely? +

Set action: deny in the PolicyLayer policy for send-sandbox-email. 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 send-sandbox-email? +

send-sandbox-email is provided by the Mcp Mailtrap MCP server (mcp-mailtrap). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.