Get posts published within a date range. Args: start_date: the start date in ISO format (YYYY-MM-DD) end_date: the end date in ISO format (YYYY-MM-DD) limit: the maximum number of posts to return
AI agents call get_by_date_range to retrieve information from Library MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a query operation on a local markdown knowledge base to retrieve content based on temporal criteria. It has no side effects—it only searches and returns data without creating, modifying, or deleting any content. It is a straightforward Read operation with minimal risk.
From the tool's definition Tool retrieves posts within a date range with parameters for start_date, end_date, and limit. The description explicitly states 'Get posts' indicating a retrieval operation. No modification, deletion, or execution of external operations is described.
Documented attack patterns abuse exactly the kind of access get_by_date_range gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Library MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for get_by_date_range:
{
"version": "1",
"default": "deny",
"tools": {
"get_by_date_range": {}
}
} get_by_date_range is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get posts published within a date range. Args: start_date: the start date in ISO format (YYYY-MM-DD) end_date: the end date in ISO format (YYYY-MM-DD) limit: the maximum number of posts to return. It is categorised as a Read tool in the Library MCP MCP Server, which means it retrieves data without modifying state.
Register the Library MCP server in PolicyLayer and add a rule for get_by_date_range: 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 Library MCP. Nothing to install.
get_by_date_range 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_by_date_range 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_by_date_range. 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_by_date_range is provided by the Library MCP server (lethain/library-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Library MCP, 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.
7 Library MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.