set_domain_smtp · TrekMail MCP Server MCP: Risk & Policy

WHAT IT DOES

What set_domain_smtp does on TrekMail MCP Server

AI agents use set_domain_smtp to create or update resources in TrekMail MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your TrekMail MCP Server environment.

WHY IT NEEDS A POLICY

Why set_domain_smtp needs a policy

This tool creates or modifies SMTP settings for outbound mail delivery, making it a Write action. While not directly moving money, misconfiguration could severely impact email operations and deliverability across an entire domain. Severity is high due to the blast radius (affects all outbound mail from a domain), though the action is reversible if corrected.

From the tool's definition Tool description states 'Set how a domain sends outbound mail' — this modifies email infrastructure configuration (SMTP settings) for a domain, which is a reversible configuration change.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_domain_smtp Rate-limited

set_domain_smtp 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": {
    "set_domain_smtp": {
      "limits": [
        {
          "counter": "set_domain_smtp_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 TrekMail MCP Server, so you can run agents against it safely.

FAQ

Questions about set_domain_smtp

What does the set_domain_smtp tool do? +

Set how a domain sends outbound mail:. It is categorised as a Write tool in the TrekMail MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_domain_smtp? +

Register the TrekMail MCP Server MCP server in PolicyLayer and add a rule for set_domain_smtp: 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 TrekMail MCP Server. Nothing to install.

What risk level is set_domain_smtp? +

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

Can I rate-limit set_domain_smtp? +

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

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

set_domain_smtp is provided by the TrekMail MCP Server MCP server (trekmail/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.