create-webhook · Mcp Mailtrap MCP: Risk & Policy

WHAT IT DOES

What create-webhook does on Mcp Mailtrap

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

WHY IT NEEDS A POLICY

Why create-webhook needs a policy

This tool creates a new webhook configuration, which is a reversible write operation. While webhooks can trigger external actions, the tool itself only creates the webhook definition. Severity is medium because misconfigured webhooks could expose data or trigger unintended external calls, and multiple webhooks could be created maliciously to spam external endpoints, but the action is reversible via deletion.

From the tool's definition Tool name 'create-webhook' and description 'Create a webhook' indicate the tool creates a new resource (webhook configuration). The incomplete description ('The response includes a') suggests it creates webhook entries in the Mcp Mailtrap system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create-webhook Rate-limited

create-webhook 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": {
    "create-webhook": {
      "limits": [
        {
          "counter": "create-webhook_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 Mailtrap, so you can run agents against it safely.

FAQ

Questions about create-webhook

What does the create-webhook tool do? +

Create a webhook. The response includes a. It is categorised as a Write tool in the Mcp Mailtrap MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create-webhook? +

Register the Mcp Mailtrap MCP server in PolicyLayer and add a rule for create-webhook: 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 Mailtrap. Nothing to install.

What risk level is create-webhook? +

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

Can I rate-limit create-webhook? +

Yes. Add a rate_limit block to the create-webhook 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 create-webhook completely? +

Set action: deny in the PolicyLayer policy for create-webhook. 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 create-webhook? +

create-webhook is provided by the Mcp Mailtrap MCP server (mcp-mailtrap). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.