switch_user · Gmail MCP Server MCP: Risk & Policy

WHAT IT DOES

What switch_user does on Gmail MCP Server

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

WHY IT NEEDS A POLICY

Why switch_user needs a policy

Switching the active user modifies the session state, which is a reversible write operation. Misuse could allow an AI agent to pivot between user accounts, potentially accessing another user's emails or performing actions on their behalf, which carries medium severity.

From the tool's definition Change the active user in a session

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

switch_user Rate-limited

switch_user 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": {
    "switch_user": {
      "limits": [
        {
          "counter": "switch_user_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 Gmail MCP Server, so you can run agents against it safely.

FAQ

Questions about switch_user

What does the switch_user tool do? +

Change the active user in a session. It is categorised as a Write tool in the Gmail MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on switch_user? +

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

What risk level is switch_user? +

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

Can I rate-limit switch_user? +

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

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

switch_user is provided by the Gmail MCP Server MCP server (kushal45/gmailmcpserver). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.