AI agents use remove_reaction 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.
Removing a reaction is a reversible action (the reaction can be re-added), so it falls under Write rather than Destructive. The blast radius is low as it only affects emoji reactions on messages.
From the tool's definition Remove the bot [reaction]" — removes a reaction added by the bot from a message
Documented attack patterns abuse exactly the kind of access remove_reaction gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Discord, and nothing reaches the server without passing your rules. This is the rule we recommend for remove_reaction:
{
"version": "1",
"default": "deny",
"tools": {
"remove_reaction": {
"limits": [
{
"counter": "remove_reaction_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}remove_reaction 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.
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Remove the bot\. 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.
Register the Discord MCP server in PolicyLayer and add a rule for remove_reaction: 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.
remove_reaction is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the remove_reaction 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.
Set action: deny in the PolicyLayer policy for remove_reaction. 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.
remove_reaction is provided by the Discord MCP server (hardheadhackerhead/discord-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Discord, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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139 Discord tools catalogued and risk-classified — across an index of 43,000+ MCP servers.