query_sql · Looker MCP Server MCP: Risk & Policy

WHAT IT DOES

What query_sql does on Looker MCP Server

AI agents invoke query_sql to trigger actions in Looker MCP 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.

WHY IT NEEDS A POLICY

Why query_sql needs a policy

The name 'query_sql' strongly implies executing SQL queries against a database. On a Looker server with broad admin capabilities, arbitrary SQL execution could read, modify, or destroy data. Since SQL can include DDL/DML (DROP, DELETE, UPDATE), the most severe applicable category is Execute (potentially Destructive), but without a description confirming destructive capability, Execute is the best fit.

From the tool's definition Tool name 'query_sql' on a server that supports 'querying the semantic model' and 'editing LookML'. The description is empty and uninformative.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

query_sql Rate-limited

query_sql 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": {
    "query_sql": {
      "limits": [
        {
          "counter": "query_sql_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 Looker MCP Server, so you can run agents against it safely.

FAQ

Questions about query_sql

What does the query_sql tool do? +

query_sql. It is categorised as a Execute tool in the Looker MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on query_sql? +

Register the Looker MCP Server MCP server in PolicyLayer and add a rule for query_sql: 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 Looker MCP Server. Nothing to install.

What risk level is query_sql? +

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

Can I rate-limit query_sql? +

Yes. Add a rate_limit block to the query_sql 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 query_sql completely? +

Set action: deny in the PolicyLayer policy for query_sql. 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 query_sql? +

query_sql is provided by the Looker MCP Server MCP server (ultrathink-solutions/looker-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.