gmail_auth_start · Mcp Gmail MCP: Risk & Policy

WHAT IT DOES

What gmail_auth_start does on Mcp Gmail

AI agents invoke gmail_auth_start to trigger actions in Mcp Gmail. 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 gmail_auth_start needs a policy

This tool executes an authentication workflow that connects the MCP server to a real Gmail account. While not destructive or financial by itself, it is an Execute-category tool because it triggers an external operation (OAuth flow) with side effects that cannot be easily reversed without manual intervention (revoking OAuth tokens).

From the tool's definition Tool initiates Google OAuth flow and directs user to browser for authentication. Description states 'Start the Google OAuth flow.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

gmail_auth_start Rate-limited

gmail_auth_start 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": {
    "gmail_auth_start": {
      "limits": [
        {
          "counter": "gmail_auth_start_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 Mcp Gmail, so you can run agents against it safely.

FAQ

Questions about gmail_auth_start

What does the gmail_auth_start tool do? +

Start the Google OAuth flow. Returns a URL to visit in a browser; on consent the auth server (. It is categorised as a Execute tool in the Mcp Gmail MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on gmail_auth_start? +

Register the Mcp Gmail MCP server in PolicyLayer and add a rule for gmail_auth_start: 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 Mcp Gmail. Nothing to install.

What risk level is gmail_auth_start? +

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

Can I rate-limit gmail_auth_start? +

Yes. Add a rate_limit block to the gmail_auth_start 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_auth_start completely? +

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

gmail_auth_start is provided by the Mcp Gmail MCP server (knowledgeislands/mcp-gmail). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.