forwardMessage · Outlook MCP: Risk & Policy

WHAT IT DOES

What forwardMessage does on Outlook

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

WHY IT NEEDS A POLICY

Why forwardMessage needs a policy

Based on the tool name and server context (Outlook email), 'forwardMessage' almost certainly forwards an existing email to one or more recipients. This is a Write operation as it sends data externally and creates a new email thread, but it does not delete or irreversibly destroy data. The severity is high because a misused forward could leak sensitive email content to unintended recipients.

From the tool's definition Tool name 'forwardMessage' on an Outlook MCP server; description is empty and uninformative.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

forwardMessage Rate-limited

forwardMessage 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": {
    "forwardMessage": {
      "limits": [
        {
          "counter": "forwardmessage_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 Outlook, so you can run agents against it safely.

FAQ

Questions about forwardMessage

What does the forwardMessage tool do? +

forwardMessage. It is categorised as a Write tool in the Outlook MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on forwardMessage? +

Register the Outlook MCP server in PolicyLayer and add a rule for forwardMessage: 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 Outlook. Nothing to install.

What risk level is forwardMessage? +

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

Can I rate-limit forwardMessage? +

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

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

forwardMessage is provided by the Outlook MCP server (lihaokun/outlook-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.