AI agents use mysql_disconnect to create or update resources in MCP MySQL Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP MySQL Server environment.
Disconnecting from a database is a reversible state change operation—the connection can be re-established. It does not retrieve data (Read), execute queries (Execute), delete data (Destructive), or move money (Financial). While it modifies system state by closing a connection, this is a standard and recoverable connection lifecycle operation with minimal blast radius.
From the tool's definition Tool name 'mysql_disconnect' and description 'Disconnect from the MySQL database' indicate a connection state management operation that terminates an active database session.
Documented attack patterns abuse exactly the kind of access mysql_disconnect gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP MySQL Server, and nothing reaches the server without passing your rules. This is the rule we recommend for mysql_disconnect:
{
"version": "1",
"default": "deny",
"tools": {
"mysql_disconnect": {
"limits": [
{
"counter": "mysql_disconnect_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}mysql_disconnect 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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Disconnect from the MySQL database. It is categorised as a Write tool in the MCP MySQL Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP MySQL Server MCP server in PolicyLayer and add a rule for mysql_disconnect: 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 MCP MySQL Server. Nothing to install.
mysql_disconnect 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 mysql_disconnect 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 mysql_disconnect. 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.
mysql_disconnect is provided by the MCP MySQL Server MCP server (sajithrw/mcp-mysql). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP MySQL Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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8 MCP MySQL Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.