discord_send_webhook_message · Discord MCP: Risk & Policy

WHAT IT DOES

What discord_send_webhook_message does on Discord

AI agents use discord_send_webhook_message 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 discord_send_webhook_message needs a policy

This tool creates new data (Discord messages) in a reversible manner. Messages can be edited or deleted afterward, making it Write rather than Destructive. The webhook token authorization means the operation can proceed without additional Discord bot permissions, but the capability itself is data creation/modification, not data destruction or code execution.

From the tool's definition The tool 'discord_send_webhook_message' creates a new message by sending through a webhook. The description explicitly states it "Send[s] a message" and "Returns the new message ID", indicating message creation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

discord_send_webhook_message Rate-limited

discord_send_webhook_message 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": {
    "discord_send_webhook_message": {
      "limits": [
        {
          "counter": "discord_send_webhook_message_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 discord_send_webhook_message

What does the discord_send_webhook_message tool do? +

Send a message through a webhook using its ID and token (no bot permissions needed — the token authorizes the send). Supports per-message username/avatar overrides and up to 10 embeds. At least one of content or embeds is required. Returns the new message ID. 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 discord_send_webhook_message? +

Register the Discord MCP server in PolicyLayer and add a rule for discord_send_webhook_message: 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 discord_send_webhook_message? +

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

Can I rate-limit discord_send_webhook_message? +

Yes. Add a rate_limit block to the discord_send_webhook_message 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 discord_send_webhook_message completely? +

Set action: deny in the PolicyLayer policy for discord_send_webhook_message. 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 discord_send_webhook_message? +

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