proton_send_email · Proton MCP Server MCP: Risk & Policy

WHAT IT DOES

What proton_send_email does on Proton MCP Server

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

WHY IT NEEDS A POLICY

Why proton_send_email needs a policy

Sending emails creates new data and modifies the email system state, but the action is reversible (sent emails can be deleted or recalled in some systems). This is a Write operation, not Execute, because it doesn't run arbitrary code—it performs a specific, bounded action.

From the tool's definition Tool description states 'Send a new email' which creates new email messages. The sibling tools include destructive operations (proton_delete_email) and read operations, placing this clearly in the Write category as it modifies data (creates email messages)…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

proton_send_email Rate-limited

proton_send_email 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": {
    "proton_send_email": {
      "limits": [
        {
          "counter": "proton_send_email_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 Proton MCP Server, so you can run agents against it safely.

FAQ

Questions about proton_send_email

What does the proton_send_email tool do? +

Send a new email. Supports plain text and HTML formats. Recipients can be a single string or array of strings. It is categorised as a Write tool in the Proton 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 proton_send_email? +

Register the Proton MCP Server MCP server in PolicyLayer and add a rule for proton_send_email: 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 Proton MCP Server. Nothing to install.

What risk level is proton_send_email? +

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

Can I rate-limit proton_send_email? +

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

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

proton_send_email is provided by the Proton MCP Server MCP server (sugar-crash-studios/proton-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.