db_query · MCP Toolkit MCP: Risk & Policy

WHAT IT DOES

What db_query does on MCP Toolkit

AI agents invoke db_query to trigger actions in MCP Toolkit. 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

The tool executes database queries, which can include SELECT (Read), INSERT/UPDATE (Write), or even DELETE/DROP (Destructive) depending on the query passed. Since the tool executes arbitrary SQL or Redis commands, the most severe applicable category is Execute. The blast radius is high because a misconfigured or malicious query could destroy data, exfiltrate sensitive information, or corrupt the database.

From the tool's definition 执行数据库查询 (Execute database query); uses parameterized queries but still runs arbitrary queries against the 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, so you can run agents against it safely.

FAQ

Questions about db_query

What does the db_query tool do? +

执行数据库查询。我会使用参数化查询来防止 SQL 注入。对于 Redis，我会自动将命令解析为正确的格式。. It is categorised as a Execute tool in the MCP Toolkit 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 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. 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 MCP server (zxfgds/mcp-toolkit). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.