AI agents call jser_weeks_between to retrieve information from JSer Info 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 historical or filtered JSer Week data based on date range parameters. It performs a passive query against the JSer.info database with no capability to modify, delete, or execute operations. The operation is read-only and safe, consistent with similar sibling tools like jser_week and jser_weeks.
From the tool's definition Tool name 'jser_weeks_between' and description 'retrieve JSer Weeks between two dates' indicate a retrieval/query operation. The Japanese description translates to 'Get JSer Weeks between two dates', which is a data retrieval operation with no side effects.
Documented attack patterns abuse exactly the kind of access jser_weeks_between gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and JSer Info MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for jser_weeks_between:
{
"version": "1",
"default": "deny",
"tools": {
"jser_weeks_between": {}
}
}jser_weeks_between is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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二つの日付の間のJSerWeekを取得します. It is categorised as a Read tool in the JSer Info MCP Server MCP Server, which means it retrieves data without modifying state.
Register the JSer Info MCP Server MCP server in PolicyLayer and add a rule for jser_weeks_between: 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 JSer Info MCP Server. Nothing to install.
jser_weeks_between 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 jser_weeks_between 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 jser_weeks_between. 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.
jser_weeks_between is provided by the JSer Info MCP Server MCP server (jser/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from JSer Info 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.
8 JSer Info MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.