mark_as_read · Gmail MCP Server MCP: Risk & Policy

WHAT IT DOES

What mark_as_read does on Gmail MCP Server

AI agents use mark_as_read 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 mark_as_read needs a policy

This tool modifies email metadata (read/unread status) but is fully reversible—the same email can be marked unread again. It has no side effects beyond updating a boolean flag and causes no data loss. It fits the Write category (creates or modifies data reversibly) rather than Read (which has no side effects) or Execute (which triggers external operations).

From the tool's definition Tool description states 'Mark an email as read', which modifies the read status flag of an email. The sibling tool 'mark_as_unread' confirms this is a reversible state-change operation on email metadata.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mark_as_read Rate-limited

mark_as_read 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": {
    "mark_as_read": {
      "limits": [
        {
          "counter": "mark_as_read_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 mark_as_read

What does the mark_as_read tool do? +

Mark an email as read. 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 mark_as_read? +

Register the Gmail MCP Server MCP server in PolicyLayer and add a rule for mark_as_read: 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 mark_as_read? +

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

Can I rate-limit mark_as_read? +

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

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

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