query_multiple_databases · Multi-Database MCP Server MCP

WHAT IT DOES

What query_multiple_databases does on Multi-Database MCP Server

AI agents invoke query_multiple_databases to trigger actions in Multi-Database 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_multiple_databases needs a policy

This tool executes arbitrary SQL queries against multiple databases at once. Since the query is user-supplied and the server supports PostgreSQL, MySQL, SQL Server, and SQLite, the queries could include DDL/DML statements (DROP, DELETE, UPDATE) across all targeted databases simultaneously. The blast radius is critical: a single misuse could irreversibly damage multiple production databases at once.

From the tool's definition "Execute the same query on multiple databases simultaneously" — runs arbitrary queries across multiple database instances in parallel

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

query_multiple_databases Rate-limited

query_multiple_databases 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_multiple_databases": {
      "limits": [
        {
          "counter": "query_multiple_databases_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 Multi-Database MCP Server, so you can run agents against it safely.

FAQ

Questions about query_multiple_databases

What does the query_multiple_databases tool do? +

Execute the same query on multiple databases simultaneously. It is categorised as a Execute tool in the Multi-Database 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_multiple_databases? +

Register the Multi-Database MCP Server MCP server in PolicyLayer and add a rule for query_multiple_databases: 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 Multi-Database MCP Server. Nothing to install.

What risk level is query_multiple_databases? +

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

Can I rate-limit query_multiple_databases? +

Yes. Add a rate_limit block to the query_multiple_databases 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_multiple_databases completely? +

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

query_multiple_databases is provided by the Multi-Database MCP Server MCP server (roshanponnappa/multidb-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.