gmail_apply_label · Mariana Google MCP: Risk & Policy

WHAT IT DOES

What gmail_apply_label does on Mariana Google MCP

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

WHY IT NEEDS A POLICY

Why gmail_apply_label needs a policy

Applying labels is a reversible mutation of Gmail message metadata. It modifies message state without deleting data or executing arbitrary code. Severity is medium because mislabeling could affect email organization and filtering, but the action is easily undone.

From the tool's definition Tool description states 'Apply a label to one or more Gmail messages'—a modification operation that adds metadata to existing messages.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

gmail_apply_label Rate-limited

gmail_apply_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_apply_label": {
      "limits": [
        {
          "counter": "gmail_apply_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 Mariana Google MCP, so you can run agents against it safely.

FAQ

Questions about gmail_apply_label

What does the gmail_apply_label tool do? +

Apply a label to one or more Gmail messages. Use gmail_list_labels to find label IDs. It is categorised as a Write tool in the Mariana Google MCP 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_apply_label? +

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

What risk level is gmail_apply_label? +

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

Can I rate-limit gmail_apply_label? +

Yes. Add a rate_limit block to the gmail_apply_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_apply_label completely? +

Set action: deny in the PolicyLayer policy for gmail_apply_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_apply_label? +

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