mark_as_unread · Gmail MCP Server MCP: Risk & Policy

WHAT IT DOES

What mark_as_unread does on Gmail MCP Server

AI agents use mark_as_unread 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_unread needs a policy

This tool modifies email state by changing the read/unread flag. It is a Write operation because it creates or modifies data reversibly—the action can be undone by marking the email as read again. It has low severity because changing email read status has minimal blast radius; it does not delete data, execute arbitrary code, move money, or trigger destructive actions.

From the tool's definition Tool name 'mark_as_unread' and description 'Mark an email as unread' indicate a state modification operation that changes email metadata (read status) reversibly.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mark_as_unread Rate-limited

mark_as_unread 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_unread": {
      "limits": [
        {
          "counter": "mark_as_unread_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_unread

What does the mark_as_unread tool do? +

Mark an email as unread. 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_unread? +

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

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

Can I rate-limit mark_as_unread? +

Yes. Add a rate_limit block to the mark_as_unread 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_unread completely? +

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

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