AI agents call cache_citation_summary 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 existing citation statistics from a local cache without creating, modifying, deleting, or executing any operations. It is a simple data retrieval operation with no side effects, fitting the Read category. The local, cached nature and statistical focus pose minimal security risk even if misused by an AI agent.
From the tool's definition Tool name 'cache_citation_summary' and description 'Get citation statistics for cached papers' indicate retrieval of pre-computed statistics without modification or execution of code. The verb 'get' and focus on 'statistics' confirm read-only access.
Documented attack patterns abuse exactly the kind of access cache_citation_summary 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_citation_summary:
{
"version": "1",
"default": "deny",
"tools": {
"cache_citation_summary": {}
}
}cache_citation_summary is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get citation statistics for cached papers. 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_citation_summary: 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_citation_summary 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_citation_summary 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_citation_summary. 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_citation_summary 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.
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17 Crossref Local tools catalogued and risk-classified — across an index of 43,000+ MCP servers.