mark_read · Mail Cal Drive MCP: Risk & Policy

WHAT IT DOES

What mark_read does on Mail Cal Drive

AI agents use mark_read to create or update resources in Mail Cal Drive — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mail Cal Drive environment.

WHY IT NEEDS A POLICY

Why mark_read needs a policy

This tool modifies email metadata (read/unread status) reversibly. It does not retrieve data (Read), execute arbitrary code (Execute), permanently delete data (Destructive), or involve financial transactions (Financial). The change is easily reversible by toggling the status back, making it a Write operation with low blast radius.

From the tool's definition Tool name 'mark_read' and description 'Mark an email message as read or unread' indicate modification of email state/metadata.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mark_read Rate-limited

mark_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_read": {
      "limits": [
        {
          "counter": "mark_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 Mail Cal Drive, so you can run agents against it safely.

FAQ

Questions about mark_read

What does the mark_read tool do? +

Mark an email message as read or unread. It is categorised as a Write tool in the Mail Cal Drive 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_read? +

Register the Mail Cal Drive MCP server in PolicyLayer and add a rule for mark_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 Mail Cal Drive. Nothing to install.

What risk level is mark_read? +

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

Can I rate-limit mark_read? +

Yes. Add a rate_limit block to the mark_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_read completely? +

Set action: deny in the PolicyLayer policy for mark_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_read? +

mark_read is provided by the Mail Cal Drive MCP server (rumbitopi/mail-cal-drive-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.