gt_mail · Claude Flow MCP: Risk & Policy

WHAT IT DOES

What gt_mail does on Claude Flow

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

WHY IT NEEDS A POLICY

Why gt_mail needs a policy

While the tool includes read and list operations (Read category), the primary capability of sending messages makes this a Write tool. Sending mail is a reversible but consequential action that modifies system state by creating new messages.

From the tool's definition Tool description states 'Send, read, or list Gas Town internal mail messages'. The 'send' capability creates new messages with side effects.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

gt_mail Rate-limited

gt_mail 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": {
    "gt_mail": {
      "limits": [
        {
          "counter": "gt_mail_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 Claude Flow, so you can run agents against it safely.

FAQ

Questions about gt_mail

What does the gt_mail tool do? +

Send, read, or list Gas Town internal mail messages. It is categorised as a Write tool in the Claude Flow MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on gt_mail? +

Register the Claude Flow MCP server in PolicyLayer and add a rule for gt_mail: 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 Claude Flow. Nothing to install.

What risk level is gt_mail? +

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

Can I rate-limit gt_mail? +

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

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

gt_mail is provided by the Claude Flow MCP server (claude-flow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.