mail_send

Send a test email to verify mail configuration is working. Provide a subject, body text, and one or more recipient addresses.

SERVERTruenas SOURCEspranab/truenas-mcp

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/spranab-truenas-mcp/mail-send.md

WHAT IT DOES

What mail_send does on Truenas

AI agents invoke mail_send to trigger actions in Truenas. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

RISK

Why mail_send is rated High

This tool triggers an external operation (sending an email) whose effects depend on arguments (subject, body, recipients). It does not simply read or write data within the system—it causes an external side effect by delivering email to specified recipients. Misuse could lead to spam or phishing emails being sent to arbitrary addresses.

From the tool's definition Send a test email to verify mail configuration is working. Provide a subject, body text, and one or more recipient addresses.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs mail_send safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Truenas, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For mail_send, this is the rule to start with:

mail_send Rate-limited

mail_send stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "mail_send": {
      "limits": [
        {
          "counter": "mail_send_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Truenas, apply this rule, and every mail_send call is checked against it from then on.

FAQ

Questions about mail_send

What does the mail_send tool do? +

Send a test email to verify mail configuration is working. Provide a subject, body text, and one or more recipient addresses. It is categorised as a Execute tool in the Truenas MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on mail_send? +

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

What risk level is mail_send? +

mail_send is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit mail_send? +

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

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

mail_send is provided by the Truenas MCP server (spranab/truenas-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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