Low Risk

list-webhooks

List all webhooks from Resend. Use to get webhook IDs and see which endpoints and events are configured. Not for listing emails, segments, or broadcasts.

How to control list-webhooks ↓

AI agents call list-webhooks to retrieve information from Email Sending MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

Low Risk

This tool retrieves and queries existing webhook configuration metadata from the Resend email service. It has no side effects—it does not create, modify, delete, or execute anything.

From the tool's definition Tool description explicitly states 'List all webhooks from Resend' and clarifies it is 'Not for listing emails, segments, or broadcasts.' The verb 'List' and retrieval of webhook configuration data (IDs, endpoints, events) are characteristic of read-only…

Documented attack patterns abuse exactly the kind of access list-webhooks gives an agent:

PolicyLayer is an MCP gateway — it sits between your AI agents and Email Sending MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for list-webhooks:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "list-webhooks": {}
  }
}

list-webhooks is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

  1. Create a free account and register Email Sending MCP — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
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Free to start. No card required.

Go deeper

What does the list-webhooks tool do? +

List all webhooks from Resend. Use to get webhook IDs and see which endpoints and events are configured. Not for listing emails, segments, or broadcasts. It is categorised as a Read tool in the Email Sending MCP MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list-webhooks? +

Register the Email Sending MCP server in PolicyLayer and add a rule for list-webhooks: 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 Email Sending MCP. Nothing to install.

What risk level is list-webhooks? +

list-webhooks is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list-webhooks? +

Yes. Add a rate_limit block to the list-webhooks 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 list-webhooks completely? +

Set action: deny in the PolicyLayer policy for list-webhooks. 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 list-webhooks? +

list-webhooks is provided by the Email Sending MCP server (resend/resend-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Email Sending MCP tool call.

Deterministic rules across all 77 Email Sending MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

77 Email Sending MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

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