mark_as_spam · Mail MCP: Risk & Policy

WHAT IT DOES

What mark_as_spam does on Mail

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

WHY IT NEEDS A POLICY

Why mark_as_spam needs a policy

Marking messages as spam moves them to a different folder—a reversible modification of message metadata and location. While this could inconvenience users by hiding legitimate emails, the action is not destructive (the messages are not deleted) and does not delete or overwrite data permanently. This is a Write operation.

From the tool's definition Tool description states 'Report messages as spam and move them to the Spam/Junk folder.' The action modifies message state and folder location, which is reversible (messages can be moved back from Spam folder).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mark_as_spam Rate-limited

mark_as_spam 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_spam": {
      "limits": [
        {
          "counter": "mark_as_spam_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Mail, so you can run agents against it safely.

FAQ

Questions about mark_as_spam

What does the mark_as_spam tool do? +

Report messages as spam and move them to the Spam/Junk folder. It is categorised as a Write tool in the Mail 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_spam? +

Register the Mail MCP server in PolicyLayer and add a rule for mark_as_spam: 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. Nothing to install.

What risk level is mark_as_spam? +

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

Can I rate-limit mark_as_spam? +

Yes. Add a rate_limit block to the mark_as_spam 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_spam completely? +

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

mark_as_spam is provided by the Mail MCP server (kpihx/mail-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.