register_webhook · Vivioo MCP: Risk & Policy

WHAT IT DOES

What register_webhook does on Vivioo

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

WHY IT NEEDS A POLICY

Why register_webhook needs a policy

This tool creates a new configuration/webhook entry in the system (Write category). Severity is medium because: (1) the blast radius is localized to webhook registration without deleting/financial impact, (2) a misconfigured webhook URL could be used to exfiltrate notifications or receive sensitive data about jobs/agents, but (3) the operation is reversible if webhooks can be unregistered.

From the tool's definition Tool registers (creates) a webhook URL to receive notifications, which modifies the system state by adding a new listener/endpoint. The description explicitly states the action is to 'register' and will set up real-time notification delivery.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

register_webhook Rate-limited

register_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": {
    "register_webhook": {
      "limits": [
        {
          "counter": "register_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 Vivioo, so you can run agents against it safely.

FAQ

Questions about register_webhook

What does the register_webhook tool do? +

Register a webhook URL to receive real-time notifications when something happens (help answers, job applications, etc). It is categorised as a Write tool in the Vivioo MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on register_webhook? +

Register the Vivioo MCP server in PolicyLayer and add a rule for register_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 Vivioo. Nothing to install.

What risk level is register_webhook? +

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

Can I rate-limit register_webhook? +

Yes. Add a rate_limit block to the register_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 register_webhook completely? +

Set action: deny in the PolicyLayer policy for register_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 register_webhook? +

register_webhook is provided by the Vivioo MCP server (vivioo-io/vivioo-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.