addSmtpAlias · MCP-YNU FastMCP Server MCP: Risk & Policy

WHAT IT DOES

What addSmtpAlias does on MCP-YNU FastMCP Server

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

WHY IT NEEDS A POLICY

Why addSmtpAlias needs a policy

This tool creates or adds new SMTP alias records for email users. While reversible (aliases can be removed), it modifies user configuration in a mail system. The context alongside similar tools like 'delSmtpAlias', 'getSmtpAlias', and 'update_user_biz_mail_alias' confirms this operates on user identity/email configuration.

From the tool's definition Tool name is 'addSmtpAlias' and description states '添加 coremail 用户 user_at_domain 的别名信息' (Add alias information for coremail user user_at_domain). The verb '添加' (add) indicates creation of new data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

addSmtpAlias Rate-limited

addSmtpAlias 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": {
    "addSmtpAlias": {
      "limits": [
        {
          "counter": "addsmtpalias_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 MCP-YNU FastMCP Server, so you can run agents against it safely.

FAQ

Questions about addSmtpAlias

What does the addSmtpAlias tool do? +

添加 coremail 用户 user_at_domain 的别名信息. It is categorised as a Write tool in the MCP-YNU FastMCP 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 addSmtpAlias? +

Register the MCP-YNU FastMCP Server MCP server in PolicyLayer and add a rule for addSmtpAlias: 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-YNU FastMCP Server. Nothing to install.

What risk level is addSmtpAlias? +

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

Can I rate-limit addSmtpAlias? +

Yes. Add a rate_limit block to the addSmtpAlias 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 addSmtpAlias completely? +

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

addSmtpAlias is provided by the MCP-YNU FastMCP Server MCP server (ynu/mcp-ynu). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.