Set the slowmode (rate limit) on a text channel. Members must wait this many seconds between messages.
AI agents use set_slowmode 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.
This tool creates or modifies a channel setting (slowmode rate limit) that can be changed back, making it a Write operation rather than Read (which would only query settings) or Execute (which would trigger an action with side effects on users). The severity is medium because misconfiguration could disrupt communication on a channel but is easily reversible and doesn't delete data or cause permanent harm.
From the tool's definition Tool modifies channel configuration (slowmode/rate limit setting) which is a reversible state change. Description states 'Set the slowmode' indicating modification of channel parameters.
Documented attack patterns abuse exactly the kind of access set_slowmode 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 set_slowmode:
{
"version": "1",
"default": "deny",
"tools": {
"set_slowmode": {
"limits": [
{
"counter": "set_slowmode_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_slowmode 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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Set the slowmode (rate limit) on a text channel. Members must wait this many seconds between messages. 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 set_slowmode: 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.
set_slowmode 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 set_slowmode 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 set_slowmode. 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.
set_slowmode 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.