update_alias · TrekMail MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_alias does on TrekMail MCP Server

AI agents use update_alias 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 update_alias needs a policy

This tool creates or modifies email alias settings in a reversible manner (status toggles can be undone). It does not delete data (Destructive), execute arbitrary code (Execute), involve financial transactions (Financial), or perform irreversible operations.

From the tool's definition Tool description states it can 'Update an alias' and explicitly allows toggling 'receiving, sending, or active/inactive status', which are reversible modifications to email alias configuration.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_alias Rate-limited

update_alias 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": {
    "update_alias": {
      "limits": [
        {
          "counter": "update_alias_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 update_alias

What does the update_alias tool do? +

Update an alias — toggle receiving, sending, or active/inactive status. Cannot change the alias address itself — delete and recreate instead. 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 update_alias? +

Register the TrekMail MCP Server MCP server in PolicyLayer and add a rule for update_alias: 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 update_alias? +

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

Can I rate-limit update_alias? +

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

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

update_alias 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.