AI agents call list_pipelines 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.
The 'list' verb strongly suggests retrieval of data (pipelines) without modification. Even in the context of a research assistant MCP server, listing pipelines is a read-only operation that queries state without side effects. No indication of execution, deletion, or financial impact. Severity is low because disclosure of pipeline metadata poses minimal risk to the system.
From the tool's definition Tool name 'list_pipelines' indicates a query or enumeration operation that retrieves existing pipeline configurations. The empty description limits specificity, but list operations are characteristically non-destructive reads.
Documented attack patterns abuse exactly the kind of access list_pipelines 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 list_pipelines:
{
"version": "1",
"default": "deny",
"tools": {
"list_pipelines": {}
}
}list_pipelines is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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list_pipelines. 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 list_pipelines: 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.
list_pipelines 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 list_pipelines 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 list_pipelines. 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.
list_pipelines 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.