reply-email · Outlook Assistant MCP: Risk & Policy

WHAT IT DOES

What reply-email does on Outlook Assistant

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

WHY IT NEEDS A POLICY

Why reply-email needs a policy

This tool creates a new email message (Write category) rather than retrieving data (Read), executing arbitrary code (Execute), deleting data (Destructive), or moving money (Financial). The severity is medium because sending emails can impact communication and potentially reach multiple recipients if replyAll is used, but it does not directly destroy data or commit financial obligations.

From the tool's definition Tool description states 'Replies to an email' with a replyAll parameter, indicating it creates and sends a new email message that modifies the state of email threads and potentially notifies multiple recipients.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

reply-email Rate-limited

reply-email 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": {
    "reply-email": {
      "limits": [
        {
          "counter": "reply-email_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 Assistant, so you can run agents against it safely.

FAQ

Questions about reply-email

What does the reply-email tool do? +

Replies to an email. Set replyAll=true to reply to all recipients. It is categorised as a Write tool in the Outlook Assistant MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on reply-email? +

Register the Outlook Assistant MCP server in PolicyLayer and add a rule for reply-email: 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 Assistant. Nothing to install.

What risk level is reply-email? +

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

Can I rate-limit reply-email? +

Yes. Add a rate_limit block to the reply-email 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 reply-email completely? +

Set action: deny in the PolicyLayer policy for reply-email. 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 reply-email? +

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