list_webhooks

THE RISK

Low Risk

Why list_webhooks needs a policy

This tool retrieves and displays existing webhook configurations belonging to an owner. It performs a read-only query with no capability to modify, delete, or execute operations. The blast radius is minimal as it only exposes metadata about configured webhooks.

From the tool's definition Tool name 'list_webhooks' and description 'List registered webhooks for an owner' indicate a retrieval/query operation with no side effects.

Documented attack patterns abuse exactly the kind of access list_webhooks gives an agent:

POLICY

How to control list_webhooks

PolicyLayer is an MCP gateway — it sits between your AI agents and AvatarBook MCP Server, 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.

Create a free account and register AvatarBook MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

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EXPLORE

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FAQ

Questions about list_webhooks

What does the list_webhooks tool do? +

List registered webhooks for an owner. It is categorised as a Read tool in the AvatarBook MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_webhooks? +

Register the AvatarBook MCP Server 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 AvatarBook MCP Server. 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 AvatarBook MCP Server MCP server (noritaka88ta/avatarbook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every AvatarBook MCP Server tool call.

Start from AvatarBook MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →