AI agents call build_citation_tree to retrieve information from Pubmed Search without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Building a citation tree typically involves fetching and organizing citation relationships between academic papers, which is a read operation. However, the description is empty, lowering confidence. The server context is a research/literature assistant, making a read classification most plausible.
From the tool's definition Tool name 'build_citation_tree' suggests constructing a citation graph/tree from academic references — a read/query operation over literature data.
Documented attack patterns abuse exactly the kind of access build_citation_tree gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Pubmed Search, and nothing reaches the server without passing your rules. This is the rule we recommend for build_citation_tree:
{
"version": "1",
"default": "deny",
"tools": {
"build_citation_tree": {}
}
}build_citation_tree is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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build_citation_tree. It is categorised as a Read tool in the Pubmed Search MCP Server, which means it retrieves data without modifying state.
Register the Pubmed Search MCP server in PolicyLayer and add a rule for build_citation_tree: 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 Pubmed Search. Nothing to install.
build_citation_tree 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 build_citation_tree 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 build_citation_tree. 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.
build_citation_tree is provided by the Pubmed Search MCP server (u9401066/pubmed-search-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Pubmed Search, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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63 Pubmed Search tools catalogued and risk-classified — across an index of 43,000+ MCP servers.