modify_webhook · Discord MCP: Risk & Policy

WHAT IT DOES

What modify_webhook does on Discord

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

WHY IT NEEDS A POLICY

Why modify_webhook needs a policy

Modifying webhooks is a Write operation: it creates or changes webhook metadata reversibly. Unlike Execute tools that trigger external operations, or Destructive tools that delete, this modifies existing webhook settings. Severity is medium because misconfiguration could redirect messages or events to unintended destinations, but changes remain reversible.

From the tool's definition Tool description states 'Modify a webhook' — a reversible change operation that alters webhook configuration (URL, name, avatar, events, etc.) without deletion or execution of external code.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

modify_webhook Rate-limited

modify_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": {
    "modify_webhook": {
      "limits": [
        {
          "counter": "modify_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 Discord, so you can run agents against it safely.

FAQ

Questions about modify_webhook

What does the modify_webhook tool do? +

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

How do I enforce a policy on modify_webhook? +

Register the Discord MCP server in PolicyLayer and add a rule for modify_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 Discord. Nothing to install.

What risk level is modify_webhook? +

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

Can I rate-limit modify_webhook? +

Yes. Add a rate_limit block to the modify_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 modify_webhook completely? +

Set action: deny in the PolicyLayer policy for modify_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 modify_webhook? +

modify_webhook is provided by the Discord MCP server (scarecr0w12/discord-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.