AI agents call health_check to retrieve information from Text-to-SQL MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Health check tools are non-destructive monitoring operations that query service status without side effects. They retrieve system state information rather than modify data or execute arbitrary code. Even in the context of a SQL server, a health check would only verify connectivity and service availability, making it a Read operation with low severity risk.
From the tool's definition Tool name 'health_check' and description '健康检查' (health check in Chinese) indicate a diagnostic/status query operation with no data modification or execution capabilities.
Documented attack patterns abuse exactly the kind of access health_check gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Text-to-SQL MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for health_check:
{
"version": "1",
"default": "deny",
"tools": {
"health_check": {}
}
}health_check is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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健康检查. It is categorised as a Read tool in the Text-to-SQL MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Text-to-SQL MCP Server MCP server in PolicyLayer and add a rule for health_check: 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 Text-to-SQL MCP Server. Nothing to install.
health_check 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 health_check 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 health_check. 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.
health_check is provided by the Text-to-SQL MCP Server MCP server (tmstack/text-to-sql-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Text-to-SQL 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.
5 Text-to-SQL MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.