AI agents call list_datasets to retrieve information from Biomart MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool is a listing/discovery function with no arguments described, typical of Read category operations that query available data sources. No side effects, modifications, deletions, or execution capabilities are implied. Though the description is empty, the tool name and server context strongly indicate a passive data retrieval function.
From the tool's definition Tool name 'list_datasets' indicates a retrieval operation that discovers or enumerates biological datasets without modification. Server description confirms it enables 'discover biological datasets' and 'explore attributes/filters' as read-only operations.
Documented attack patterns abuse exactly the kind of access list_datasets gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Biomart MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for list_datasets:
{
"version": "1",
"default": "deny",
"tools": {
"list_datasets": {}
}
}list_datasets is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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list_datasets. It is categorised as a Read tool in the Biomart MCP MCP Server, which means it retrieves data without modifying state.
Register the Biomart MCP server in PolicyLayer and add a rule for list_datasets: 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 Biomart MCP. Nothing to install.
list_datasets 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_datasets 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_datasets. 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_datasets is provided by the Biomart MCP server (jzinno/biomart-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Biomart MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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8 Biomart MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.