AI agents call list_portfolios to retrieve information from Virtualization without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool name indicates a query or listing operation ('list'), which typically retrieves data without side effects. However, the empty description and the mismatch with the server's virtualization focus (VM management, sandboxes, networking) create ambiguity. The tool may be misnamed, belong to a different server context, or retrieve portfolio configuration data.
From the tool's definition Tool name 'list_portfolios' suggests data retrieval; description is empty, limiting certainty about actual functionality.
Documented attack patterns abuse exactly the kind of access list_portfolios gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Virtualization, and nothing reaches the server without passing your rules. This is the rule we recommend for list_portfolios:
{
"version": "1",
"default": "deny",
"tools": {
"list_portfolios": {}
}
}list_portfolios 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.
list_portfolios. It is categorised as a Read tool in the Virtualization MCP Server, which means it retrieves data without modifying state.
Register the Virtualization MCP server in PolicyLayer and add a rule for list_portfolios: 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 Virtualization. Nothing to install.
list_portfolios 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_portfolios 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_portfolios. 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_portfolios is provided by the Virtualization MCP server (sandraschi/virtualization-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Virtualization, 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.
56 Virtualization tools catalogued and risk-classified — across an index of 43,000+ MCP servers.