mysql_query · Mysql MCP: Risk & Policy

WHAT IT DOES

What mysql_query does on Mysql

AI agents invoke mysql_query to trigger actions in Mysql. 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.

WHY IT NEEDS A POLICY

Why mysql_query needs a policy

Because the tool accepts and runs arbitrary MySQL queries, it spans Read through Destructive. Under the most-severe-applicable rule, it must be classified as Destructive (DROP/DELETE are possible), but since it also covers non-destructive queries, Execute is the correct category when the effect depends on arguments.

From the tool's definition 'Execute any MySQL query' — the tool runs arbitrary SQL, which can include SELECT, INSERT, UPDATE, DELETE, DROP, or any other statement.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mysql_query Rate-limited

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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "mysql_query": {
      "limits": [
        {
          "counter": "mysql_query_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Mysql, so you can run agents against it safely.

FAQ

Questions about mysql_query

What does the mysql_query tool do? +

Execute any MySQL query and return results. It is categorised as a Execute tool in the Mysql MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on mysql_query? +

Register the Mysql 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 Mysql. Nothing to install.

What risk level is mysql_query? +

mysql_query is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit mysql_query? +

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.

How do I block mysql_query completely? +

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.

What MCP server provides mysql_query? +

mysql_query is provided by the Mysql MCP server (myheisenberg/mysql-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.