pin_message · Discord MCP: Risk & Policy

WHAT IT DOES

What pin_message does on Discord

AI agents use pin_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 pin_message needs a policy

Pinning a message modifies channel state by highlighting/organizing a message, making it permanently visible in the channel's pinned list. This is reversible (messages can be unpinned), non-destructive, and has no financial impact. However, it affects channel organization and visibility which is why severity is medium rather than low.

From the tool's definition Tool name 'pin_message' and description 'Pin a message in a channel' indicate a message state modification operation. Pinning is a reversible action that modifies message metadata without deleting or destroying data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

pin_message Rate-limited

pin_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": {
    "pin_message": {
      "limits": [
        {
          "counter": "pin_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 pin_message

What does the pin_message tool do? +

Pin a message in a channel. 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 pin_message? +

Register the Discord MCP server in PolicyLayer and add a rule for pin_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 pin_message? +

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

Can I rate-limit pin_message? +

Yes. Add a rate_limit block to the pin_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 pin_message completely? +

Set action: deny in the PolicyLayer policy for pin_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 pin_message? +

pin_message 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.