gmail_send_email · Google MCP: Risk & Policy

WHAT IT DOES

What gmail_send_email does on Google

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

WHY IT NEEDS A POLICY

Why gmail_send_email needs a policy

Sending email creates new data (messages) in the user's Gmail account and is reversible (can be deleted), making it a Write action. Severity is medium because misuse could cause reputational harm (spam, phishing, scams) or information disclosure, but the tool itself does not move money (Financial), delete data (Destructive), or execute arbitrary code (Execute).

From the tool's definition Tool name 'gmail_send_email' and description 'Send an email via Gmail' indicate creation of new email messages, which is a write operation that modifies the mailbox state by adding a message.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

gmail_send_email Rate-limited

gmail_send_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": {
    "gmail_send_email": {
      "limits": [
        {
          "counter": "gmail_send_email_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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

FAQ

Questions about gmail_send_email

What does the gmail_send_email tool do? +

Send an email via Gmail. It is categorised as a Write tool in the Google MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on gmail_send_email? +

Register the Google MCP server in PolicyLayer and add a rule for gmail_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 Google. Nothing to install.

What risk level is gmail_send_email? +

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

Can I rate-limit gmail_send_email? +

Yes. Add a rate_limit block to the gmail_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 gmail_send_email completely? +

Set action: deny in the PolicyLayer policy for gmail_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 gmail_send_email? +

gmail_send_email is provided by the Google MCP server (psckeithw/mcp-google). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.