db_execute_query · Custom MCP Database Server MCP

WHAT IT DOES

What db_execute_query does on Custom MCP Database Server

AI agents invoke db_execute_query to trigger actions in Custom MCP Database 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 db_execute_query needs a policy

This tool executes code (SQL/query operations) against multiple database systems with effects that vary based on arguments passed by the agent. While the server claims to provide security controls and hide credentials, the tool itself performs query execution, which is an Execute category action.

From the tool's definition Tool name 'db_execute_query' combined with server description stating it 'allows AI code agents to securely execute queries against various databases (PostgreSQL, MySQL, MongoDB, Oracle)' indicates the tool runs arbitrary database queries whose effects depend…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

db_execute_query Rate-limited

db_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": {
    "db_execute_query": {
      "limits": [
        {
          "counter": "db_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 Custom MCP Database Server, so you can run agents against it safely.

FAQ

Questions about db_execute_query

What does the db_execute_query tool do? +

db_execute_query. It is categorised as a Execute tool in the Custom MCP Database 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 db_execute_query? +

Register the Custom MCP Database Server MCP server in PolicyLayer and add a rule for db_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 Custom MCP Database Server. Nothing to install.

What risk level is db_execute_query? +

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

Can I rate-limit db_execute_query? +

Yes. Add a rate_limit block to the db_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 db_execute_query completely? +

Set action: deny in the PolicyLayer policy for db_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 db_execute_query? +

db_execute_query is provided by the Custom MCP Database Server MCP server (renanlido/custom-mcp-database). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.