create_message_token · TrekMail MCP Server MCP

WHAT IT DOES

What create_message_token does on TrekMail MCP Server

AI agents use create_message_token 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 create_message_token needs a policy

This tool creates authentication credentials that persist and grant ongoing access to mailbox operations. While the immediate action is creating a token (Write), the token's grants span Read, Write, and Execute (send) capabilities. However, the tool itself performs a Write action—creating a new credential object.

From the tool's definition Tool description states it 'Create[s] a message API token' and 'grants access to read, write, or send messages'. The act of creating a token is a Write operation (creates a credential artifact).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_message_token Rate-limited

create_message_token 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": {
    "create_message_token": {
      "limits": [
        {
          "counter": "create_message_token_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 create_message_token

What does the create_message_token tool do? +

Create a message API token for a mailbox. The token grants access to read, write, or send messages for that mailbox. The plain token is returned only once. 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 create_message_token? +

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

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

Can I rate-limit create_message_token? +

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

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

create_message_token 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.