db_query · MCP Toolkit Server MCP: Risk & Policy

WHAT IT DOES

What db_query does on MCP Toolkit Server

AI agents invoke db_query to trigger actions in MCP Toolkit 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_query needs a policy

This tool executes arbitrary SQL, which can include SELECT (Read), INSERT/UPDATE (Write), DELETE/DROP (Destructive), or other dangerous statements. Since the description does not restrict query types and explicitly says 'execute a SQL query,' the most severe applicable category is Execute (potentially Destructive).

From the tool's definition "Execute a SQL query against a SQLite database" — the tool runs arbitrary SQL statements against a database.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

db_query Rate-limited

db_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_query": {
      "limits": [
        {
          "counter": "db_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 MCP Toolkit Server, so you can run agents against it safely.

FAQ

Questions about db_query

What does the db_query tool do? +

Execute a SQL query against a SQLite database and return the results. Modes: -. It is categorised as a Execute tool in the MCP Toolkit 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_query? +

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

What risk level is db_query? +

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

Can I rate-limit db_query? +

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

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

db_query is provided by the MCP Toolkit Server MCP server (vyshnavi-nandyala/mcp-toolkit-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.