send_email · Microsoft MCP: Risk & Policy

WHAT IT DOES

What send_email does on Microsoft MCP

AI agents invoke send_email to trigger actions in Microsoft MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why send_email needs a policy

Sending an email is an irreversible external operation: once sent, the message and any attached files are delivered to recipients outside the user's control. This goes beyond a Write (which implies reversible data modification) and constitutes an Execute action with high severity, as a misused agent could send sensitive data or malicious content to arbitrary recipients.

From the tool's definition 'Send an email immediately' — triggers an external, real-world communication operation that cannot be recalled once delivered; 'with file path(s) as attachments' extends the blast radius by potentially exfiltrating local files

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send_email Rate-limited

send_email stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "send_email": {
      "limits": [
        {
          "counter": "send_email_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Microsoft MCP, so you can run agents against it safely.

FAQ

Questions about send_email

What does the send_email tool do? +

Send an email immediately with file path(s) as attachments. It is categorised as a Execute tool in the Microsoft MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on send_email? +

Register the Microsoft MCP server in PolicyLayer and add a rule for send_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 Microsoft MCP. Nothing to install.

What risk level is send_email? +

send_email is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit send_email? +

Yes. Add a rate_limit block to the send_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 send_email completely? +

Set action: deny in the PolicyLayer policy for send_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 send_email? +

send_email is provided by the Microsoft MCP server (purva-kashyap/microsoft-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.