AI agents call cache_top_cited to retrieve information from Crossref Local without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries cached citation data to identify highly-cited papers. It performs no side effects, does not execute code or commands, does not create or modify data, and does not delete or move money. The operation is purely informational/analytical in nature, consistent with the Read category.
From the tool's definition Tool name 'cache_top_cited' and description 'Get top cited papers from cache' indicate a retrieval operation. The verb 'Get' and the lack of any modification, deletion, or execution language confirm this is a read-only query.
Documented attack patterns abuse exactly the kind of access cache_top_cited gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crossref Local, and nothing reaches the server without passing your rules. This is the rule we recommend for cache_top_cited:
{
"version": "1",
"default": "deny",
"tools": {
"cache_top_cited": {}
}
}cache_top_cited is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Get top cited papers from cache. It is categorised as a Read tool in the Crossref Local MCP Server, which means it retrieves data without modifying state.
Register the Crossref Local MCP server in PolicyLayer and add a rule for cache_top_cited: 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 Crossref Local. Nothing to install.
cache_top_cited 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 cache_top_cited 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 cache_top_cited. 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.
cache_top_cited is provided by the Crossref Local MCP server (ywatanabe1989/crossref-local). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Crossref Local, 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.
17 Crossref Local tools catalogued and risk-classified — across an index of 43,000+ MCP servers.