Assign a role to a member. Both role and member names are fuzzy-matched.
AI agents use assign_role 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 role assignments, a reversible change to member permissions. It is Write rather than Execute because it does not run arbitrary code or external operations—it directly manages a Discord resource. It is not Destructive because role assignments can be reverted by removing the role.
From the tool's definition Tool description states "Assign a role to a member", which modifies user permissions and role memberships. The fuzzy-matching behavior adds execution risk if the tool misidentifies targets.
Documented attack patterns abuse exactly the kind of access assign_role 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 assign_role:
{
"version": "1",
"default": "deny",
"tools": {
"assign_role": {
"limits": [
{
"counter": "assign_role_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}assign_role 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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Assign a role to a member. Both role and member names are fuzzy-matched. 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 assign_role: 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.
assign_role 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 assign_role 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 assign_role. 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.
assign_role 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.