Low Risk

query

Execute a SELECT query

How to control query ↓

What query does on MCP-MongoDB-MySQL-Server

AI agents call query to retrieve information from MCP-MongoDB-MySQL-Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

Low Risk

Why query needs a policy

SELECT queries are read-only operations that retrieve data from databases without side effects. While they could potentially be misused to access sensitive data, this is a fundamental database read operation with no capability to modify, delete, or execute arbitrary code. The explicit mention of SELECT queries confirms the read-only nature.

From the tool's definition Tool name is 'query' with description 'Execute a SELECT query'. SELECT queries retrieve data without modification or deletion.

Documented attack patterns abuse exactly the kind of access query gives an agent:

How to control query

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP-MongoDB-MySQL-Server, and nothing reaches the server without passing your rules. This is the rule we recommend for query:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "query": {}
  }
}

query is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

  1. Create a free account and register MCP-MongoDB-MySQL-Server — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
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Related tools and policies

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Questions about query

What does the query tool do? +

Execute a SELECT query. It is categorised as a Read tool in the MCP-MongoDB-MySQL-Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on query? +

Register the MCP-MongoDB-MySQL-Server MCP server in PolicyLayer and add a rule for 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-MongoDB-MySQL-Server. Nothing to install.

What risk level is query? +

query is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit query? +

Yes. Add a rate_limit block to the 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 query completely? +

Set action: deny in the PolicyLayer policy for 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 query? +

query is provided by the MCP-MongoDB-MySQL-Server MCP server (yaoxiaolinglong/mcp-mongodb-mysql-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP-MongoDB-MySQL-Server tool call.

Start from MCP-MongoDB-MySQL-Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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14 MCP-MongoDB-MySQL-Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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