mark_as_read · Zimbra MCP Server MCP: Risk & Policy

WHAT IT DOES

What mark_as_read does on Zimbra MCP Server

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

WHY IT NEEDS A POLICY

Why mark_as_read needs a policy

Marking emails as read/unread is a reversible modification of email metadata. It does not delete, destroy, or execute external operations. While it changes data state (the read flag), it is not destructive and has minimal blast radius—users can easily reverse the action by unmarking. This fits the Write category as it modifies data reversibly.

From the tool's definition Tool marks emails as read or unread, which modifies the state of email messages. This is a state change operation that affects how emails are displayed and tracked in the mailbox.

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 Zimbra 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 emails as read or unread. It is categorised as a Write tool in the Zimbra 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 Zimbra 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 Zimbra 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 Zimbra MCP Server MCP server (jeremie-lesage/zimbra-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.