gmail_message_label · Mcp Gmail MCP: Risk & Policy

WHAT IT DOES

What gmail_message_label does on Mcp Gmail

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

WHY IT NEEDS A POLICY

Why gmail_message_label needs a policy

The tool modifies existing data (message labels) in a way that can be undone by removing labels later. It is not destructive (labels can be removed), not financial, not execute-level code execution, and not merely read-only. It falls squarely into Write: a reversible modification of data state within Gmail.

From the tool's definition 'Add one or more labels to a message' — this modifies message metadata by attaching labels, a reversible operation that does not delete or create the message itself, nor does it send communications or move funds.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

gmail_message_label Rate-limited

gmail_message_label 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_message_label": {
      "limits": [
        {
          "counter": "gmail_message_label_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 Mcp Gmail, so you can run agents against it safely.

FAQ

Questions about gmail_message_label

What does the gmail_message_label tool do? +

Add one or more labels to a message. It is categorised as a Write tool in the Mcp Gmail 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_message_label? +

Register the Mcp Gmail MCP server in PolicyLayer and add a rule for gmail_message_label: 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_message_label? +

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

Can I rate-limit gmail_message_label? +

Yes. Add a rate_limit block to the gmail_message_label 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_message_label completely? +

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

gmail_message_label 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.