mark_message_read · MCP Agent Mail MCP: Risk & Policy

WHAT IT DOES

What mark_message_read does on MCP Agent Mail

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

WHY IT NEEDS A POLICY

Why mark_message_read needs a policy

Marking a message as read modifies state (metadata) but does not create, retrieve, or permanently delete data. It is reversible (can be unmarked). The action has minimal blast radius in a multi-agent coordination context. Classified as Write rather than Read because it performs a state mutation, not a pure query.

From the tool's definition Tool name 'mark_message_read' indicates state modification. Description is empty, providing no detail. Based on the server's function as a 'coordination layer' with 'message threading and searchable history', this tool likely updates message read status—a…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mark_message_read Rate-limited

mark_message_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_message_read": {
      "limits": [
        {
          "counter": "mark_message_read_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 MCP Agent Mail, so you can run agents against it safely.

FAQ

Questions about mark_message_read

What does the mark_message_read tool do? +

mark_message_read. It is categorised as a Write tool in the MCP Agent 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_message_read? +

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

What risk level is mark_message_read? +

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

Can I rate-limit mark_message_read? +

Yes. Add a rate_limit block to the mark_message_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_message_read completely? +

Set action: deny in the PolicyLayer policy for mark_message_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_message_read? +

mark_message_read is provided by the MCP Agent Mail MCP server (omelchmichael/mcp_agent_mail). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.