Grant a role to a user (MySQL 8.0+).
AI agents use grant_role_to_user to create or update resources in Mysql — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mysql environment.
Granting a role to a user modifies access control permissions in the database. This is a Write operation (modifying user privileges/roles) but has high severity because it can escalate privileges, potentially giving a user elevated access to sensitive data or administrative capabilities. It is reversible (roles can be revoked), so it does not qualify as Destructive.
From the tool's definition Grant a role to a user
Documented attack patterns abuse exactly the kind of access grant_role_to_user gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mysql, and nothing reaches the server without passing your rules. This is the rule we recommend for grant_role_to_user:
{
"version": "1",
"default": "deny",
"tools": {
"grant_role_to_user": {
"limits": [
{
"counter": "grant_role_to_user_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}grant_role_to_user 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.
Free to start. No card required.
Grant a role to a user (MySQL 8.0+). It is categorised as a Write tool in the Mysql MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Mysql MCP server in PolicyLayer and add a rule for grant_role_to_user: 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 Mysql. Nothing to install.
grant_role_to_user 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 grant_role_to_user 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 grant_role_to_user. 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.
grant_role_to_user is provided by the Mysql MCP server (mukul975/mysql-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mysql, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
233 Mysql tools catalogued and risk-classified — across an index of 43,000+ MCP servers.