trigger_webhook · Zhook MCP: Risk & Policy

WHAT IT DOES

What trigger_webhook does on Zhook

AI agents invoke trigger_webhook to trigger actions in Zhook. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why trigger_webhook needs a policy

This tool executes an outbound action (sending a webhook/HTTP request) to an external service. While labeled 'test', it still performs a real network operation with side effects determined by the receiving endpoint. It is not merely reading data (Read), nor is it persistently creating/modifying configuration (Write would be for managing hooks themselves).

From the tool's definition Tool description states 'Send a test webhook event to a specific Hook' which triggers an external operation (HTTP request) to a configured webhook URL. The effect depends on what the receiving endpoint does with the payload.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

trigger_webhook Rate-limited

trigger_webhook stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "trigger_webhook": {
      "limits": [
        {
          "counter": "trigger_webhook_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Zhook, so you can run agents against it safely.

FAQ

Questions about trigger_webhook

What does the trigger_webhook tool do? +

Send a test webhook event to a specific Hook. This mimics a real third-party service sending data to the hook URL. It is categorised as a Execute tool in the Zhook MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on trigger_webhook? +

Register the Zhook MCP server in PolicyLayer and add a rule for trigger_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 Zhook. Nothing to install.

What risk level is trigger_webhook? +

trigger_webhook is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit trigger_webhook? +

Yes. Add a rate_limit block to the trigger_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 trigger_webhook completely? +

Set action: deny in the PolicyLayer policy for trigger_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 trigger_webhook? +

trigger_webhook is provided by the Zhook MCP server (zhookteam/zhook-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.