update_webhook · Mcp Github MCP: Risk & Policy

WHAT IT DOES

What update_webhook does on Mcp Github

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

WHY IT NEEDS A POLICY

Why update_webhook needs a policy

This is a reversible modification action (Write category). Severity is high because: (1) webhook modifications can redirect sensitive repository events to attacker-controlled endpoints, enabling credential theft or data exfiltration; (2) it affects repository security posture and integration behavior; (3) an AI agent could be tricked into reconfiguring webhooks to malicious targets.

From the tool's definition Tool updates webhook configuration ("Actualiza un webhook existente"), which modifies existing webhook settings on GitHub repositories.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_webhook Rate-limited

update_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": {
    "update_webhook": {
      "limits": [
        {
          "counter": "update_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 Github, so you can run agents against it safely.

FAQ

Questions about update_webhook

What does the update_webhook tool do? +

Actualiza un webhook existente. It is categorised as a Write tool in the Mcp Github MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_webhook? +

Register the Mcp Github MCP server in PolicyLayer and add a rule for update_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 Github. Nothing to install.

What risk level is update_webhook? +

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

Can I rate-limit update_webhook? +

Yes. Add a rate_limit block to the update_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 update_webhook completely? +

Set action: deny in the PolicyLayer policy for update_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 update_webhook? +

update_webhook is provided by the Mcp Github MCP server (pblarismendi/mcp-github-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.