gmail_messages_batch_modify · Mcp Gmail MCP: Risk & Policy

WHAT IT DOES

What gmail_messages_batch_modify does on Mcp Gmail

AI agents use gmail_messages_batch_modify 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_messages_batch_modify needs a policy

This tool modifies message labels (metadata) but does not delete messages, send emails, or move money. Label changes are reversible (labels can be re-added or removed). While it operates on up to 1000 messages at once, the reversible nature and lack of destructive capability place it in Write rather than Destructive.

From the tool's definition Tool description states 'Add and/or remove labels on up to 1000 messages' — modifying message labels is a reversible change to message metadata. The batch operation affects up to 1000 items, increasing blast radius.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

gmail_messages_batch_modify Rate-limited

gmail_messages_batch_modify 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_messages_batch_modify": {
      "limits": [
        {
          "counter": "gmail_messages_batch_modify_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_messages_batch_modify

What does the gmail_messages_batch_modify tool do? +

Add and/or remove labels on up to 1000 messages in a single Gmail. 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_messages_batch_modify? +

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

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

Can I rate-limit gmail_messages_batch_modify? +

Yes. Add a rate_limit block to the gmail_messages_batch_modify 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_messages_batch_modify completely? +

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

gmail_messages_batch_modify 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.