AI agents call get_column_examples to retrieve information from JVLink MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves example values from database columns to help understand data formats. It performs a passive query operation with no side effects—no data is created, modified, deleted, or executed. It falls squarely into the Read category with low severity since it only returns informational samples from existing data.
From the tool's definition Tool name 'get_column_examples' and description '特定カラムの値の例を取得（データ形式理解用）' (Get examples of values for a specific column for understanding data format) indicate retrieval of sample data without modification, deletion, or execution.
Documented attack patterns abuse exactly the kind of access get_column_examples gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and JVLink MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for get_column_examples:
{
"version": "1",
"default": "deny",
"tools": {
"get_column_examples": {}
}
}get_column_examples is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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特定カラムの値の例を取得（データ形式理解用）. It is categorised as a Read tool in the JVLink MCP Server MCP Server, which means it retrieves data without modifying state.
Register the JVLink MCP Server MCP server in PolicyLayer and add a rule for get_column_examples: 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 JVLink MCP Server. Nothing to install.
get_column_examples is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_column_examples 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.
Set action: deny in the PolicyLayer policy for get_column_examples. 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.
get_column_examples is provided by the JVLink MCP Server MCP server (miyamamoto/jvlink-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from JVLink MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
25 JVLink MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.