AI agents call health_check to retrieve information from J Quants Doc without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Health check tools query system status and return diagnostic information with no side effects. This is a Read category tool with low severity—even if misused by an agent, it only retrieves status data and poses minimal risk. The confidence is high because health checks are a well-established, non-destructive pattern.
From the tool's definition The tool is described as 'ヘルスチェック用の簡易Tool' (a simple tool for health checks). Health checks retrieve status information without modifying, deleting, or executing code. The tool name 'health_check' and its purpose indicate a read-only diagnostic operation.
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 J Quants Doc, 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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ヘルスチェック用の簡易Tool。. It is categorised as a Read tool in the J Quants Doc MCP Server, which means it retrieves data without modifying state.
Register the J Quants Doc 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 J Quants Doc. 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 J Quants Doc MCP server (j-quants/j-quants-doc-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from J Quants Doc, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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7 J Quants Doc tools catalogued and risk-classified — across an index of 43,000+ MCP servers.