mysql_show_columns

THE RISK

Low Risk

Why mysql_show_columns needs a policy

This tool queries and retrieves metadata about table structure (columns, their properties) without modifying data or executing code. It is a pure read operation with minimal blast radius—knowledge of column names and types poses no risk of data loss or unauthorized modifications. Classified as Read with low severity.

From the tool's definition Tool name 'mysql_show_columns' and description indicating it retrieves column information ('获取表的列信息' = 'get table column information'). Returns JSON string of table column info with no write, delete, or execution capabilities.

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

POLICY

How to control mysql_show_columns

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "mysql_show_columns": {}
  }
}

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

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

CAP THIS TOOL →

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EXPLORE

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
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Rate Limiting MCP Tool Calls: A Practical Guide →
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FAQ

Questions about mysql_show_columns

What does the mysql_show_columns tool do? +

获取表的列信息 Args: table: 表名 database: 数据库名称 (可选，默认使用当前连接的数据库) Returns: 表列信息的JSON字符串. It is categorised as a Read tool in the MySQL MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on mysql_show_columns? +

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

What risk level is mysql_show_columns? +

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

Can I rate-limit mysql_show_columns? +

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

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

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

Enforce policy on every MySQL MCP Server tool call.

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

CHECK YOUR STACK →