Medium Risk

outlook_add_attachment

Add an attachment to an email draft

How to control outlook_add_attachment ↓

What outlook_add_attachment does on Outlook

AI agents use outlook_add_attachment 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.

Medium Risk

Why outlook_add_attachment needs a policy

This tool modifies draft email state by adding attachments, which is a reversible write operation. It does not execute code, delete data, move money, or trigger external systems beyond the attachment mechanism itself.

From the tool's definition Tool name 'outlook_add_attachment' and description 'Add an attachment to an email draft' indicate modification of draft email content by attaching files.

Documented attack patterns abuse exactly the kind of access outlook_add_attachment gives an agent:

How to control outlook_add_attachment

PolicyLayer is an MCP gateway — it sits between your AI agents and Outlook, and nothing reaches the server without passing your rules. This is the rule we recommend for outlook_add_attachment:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "outlook_add_attachment": {
      "limits": [
        {
          "counter": "outlook_add_attachment_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

outlook_add_attachment 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.

  1. Create a free account and register Outlook — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

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Related tools and policies

Go deeper

Questions about outlook_add_attachment

What does the outlook_add_attachment tool do? +

Add an attachment to an email draft. 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 outlook_add_attachment? +

Register the Outlook MCP server in PolicyLayer and add a rule for outlook_add_attachment: 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 outlook_add_attachment? +

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

Can I rate-limit outlook_add_attachment? +

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

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

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

Enforce policy on every Outlook tool call.

Start from Outlook, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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43 Outlook tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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