execute_query · Bq MCP: Risk & Policy

WHAT IT DOES

What execute_query does on Bq

AI agents invoke execute_query to trigger actions in Bq. 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 execute_query needs a policy

Executing arbitrary SQL queries is an Execute-category operation because it triggers external database operations whose effects depend on the query arguments. While the server description mentions 'cost control' and 'secure' execution, these are mitigations rather than category determinants.

From the tool's definition Tool named 'execute_query' on a BigQuery server that 'enables secure SQL query execution'; the name and server context indicate this tool runs SQL queries against BigQuery, which is code execution against a database.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

execute_query Rate-limited

execute_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": {
    "execute_query": {
      "limits": [
        {
          "counter": "execute_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 Bq, so you can run agents against it safely.

FAQ

Questions about execute_query

What does the execute_query tool do? +

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

How do I enforce a policy on execute_query? +

Register the Bq MCP server in PolicyLayer and add a rule for execute_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 Bq. Nothing to install.

What risk level is execute_query? +

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

Can I rate-limit execute_query? +

Yes. Add a rate_limit block to the execute_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 execute_query completely? +

Set action: deny in the PolicyLayer policy for execute_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 execute_query? +

execute_query is provided by the Bq MCP server (takada-at/bq_mcp_server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.