update_message_flags · TrekMail MCP Server MCP

WHAT IT DOES

What update_message_flags does on TrekMail MCP Server

AI agents use update_message_flags 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_message_flags needs a policy

This tool modifies message metadata reversibly without deleting data or executing arbitrary code. It changes the state of existing messages (flag status) but the changes can be undone by updating flags again. This is a classic Write operation.

From the tool's definition update_message_flags updates (modifies) message flags such as read/unread and starred/unstarred status. The description explicitly states 'Update flags' and requires 'messages:write scope', indicating write-level permissions.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_message_flags Rate-limited

update_message_flags 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_message_flags": {
      "limits": [
        {
          "counter": "update_message_flags_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_message_flags

What does the update_message_flags tool do? +

Update flags (read/unread, starred/unstarred) on a message by IMAP UID. Requires a message token with messages:write scope. 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_message_flags? +

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

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

Can I rate-limit update_message_flags? +

Yes. Add a rate_limit block to the update_message_flags 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_message_flags completely? +

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

update_message_flags 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.