send-message · Discord MCP Server MCP: Risk & Policy

WHAT IT DOES

What send-message does on Discord MCP Server

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

WHY IT NEEDS A POLICY

Why send-message needs a policy

Sending messages is a reversible write operation that creates new data in Discord. Severity is medium rather than high because: (1) message creation is generally non-destructive and can be mitigated by moderation/deletion, (2) blast radius is limited to a single channel unless looped, and (3) worst case is spam/disruption rather than permanent data loss or financial impact.

From the tool's definition Tool description states "Send a message to a Discord channel" - this creates new message data in Discord. The sibling tools confirm a message-handling context (read-messages, react-to-message).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send-message Rate-limited

send-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": {
    "send-message": {
      "limits": [
        {
          "counter": "send-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 MCP Server, so you can run agents against it safely.

FAQ

Questions about send-message

What does the send-message tool do? +

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

How do I enforce a policy on send-message? +

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

What risk level is send-message? +

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

Can I rate-limit send-message? +

Yes. Add a rate_limit block to the send-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 send-message completely? +

Set action: deny in the PolicyLayer policy for send-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 send-message? +

send-message is provided by the Discord MCP Server MCP server (rossh121/discord-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.