Execute a SQL query on the connected MySQL database
AI agents invoke mysql_query to trigger actions in MCP MySQL Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
This tool executes arbitrary SQL queries against a MySQL database. While named 'query', it can run any SQL including SELECT, INSERT, UPDATE, DELETE, DROP, or TRUNCATE. The most severe applicable category is Execute (potentially Destructive depending on the query), but since the tool itself is a general-purpose SQL executor, Execute is the correct base category.
From the tool's definition "Execute a SQL query on the connected MySQL database" — arbitrary SQL execution
Documented attack patterns abuse exactly the kind of access mysql_query 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_query:
{
"version": "1",
"default": "deny",
"tools": {
"mysql_query": {
"limits": [
{
"counter": "mysql_query_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}mysql_query stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Execute a SQL query on the connected MySQL database. It is categorised as a Execute tool in the MCP MySQL Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the MCP MySQL Server MCP server in PolicyLayer and add a rule for mysql_query: 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_query is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the mysql_query 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_query. 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_query 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.