apply_gmail_label · Gmail MCP Server MCP: Risk & Policy

WHAT IT DOES

What apply_gmail_label does on Gmail MCP Server

AI agents use apply_gmail_label 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 apply_gmail_label needs a policy

Applying a label is a write operation that modifies email metadata and organization, but it is fully reversible (labels can be removed). This is less severe than destructive operations but constitutes data modification. The empty description lowers confidence slightly, but the context from sibling tools and server function clarify intent.

From the tool's definition Tool name 'apply_gmail_label' combined with sibling tools including 'create_gmail_label' and 'mark_gmail_*' operations that modify email metadata. The server description states it allows Claude to 'manage emails'.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

apply_gmail_label Rate-limited

apply_gmail_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": {
    "apply_gmail_label": {
      "limits": [
        {
          "counter": "apply_gmail_label_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 Gmail MCP Server, so you can run agents against it safely.

FAQ

Questions about apply_gmail_label

What does the apply_gmail_label tool do? +

apply_gmail_label. 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 apply_gmail_label? +

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

What risk level is apply_gmail_label? +

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

Can I rate-limit apply_gmail_label? +

Yes. Add a rate_limit block to the apply_gmail_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 apply_gmail_label completely? +

Set action: deny in the PolicyLayer policy for apply_gmail_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 apply_gmail_label? +

apply_gmail_label is provided by the Gmail MCP Server MCP server (stevesimpson418/gmail-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.