AI agents call set_cardinality to retrieve information from Amazon EKS MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool description says it retrieves (gets) a count of members in a set, which is a read-only operation with no side effects. Confidence is slightly reduced because the tool name 'set_cardinality' and its presence on an EKS server is unusual, but the description clearly indicates a non-mutating query operation.
From the tool's definition Get number of members in set.
Documented attack patterns abuse exactly the kind of access set_cardinality gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Amazon EKS MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for set_cardinality:
{
"version": "1",
"default": "deny",
"tools": {
"set_cardinality": {}
}
} set_cardinality is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get number of members in set. It is categorised as a Read tool in the Amazon EKS MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Amazon EKS MCP Server MCP server in PolicyLayer and add a rule for set_cardinality: 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 Amazon EKS MCP Server. Nothing to install.
set_cardinality 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 set_cardinality 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 set_cardinality. 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.
set_cardinality is provided by the Amazon EKS MCP Server MCP server (awslabs.eks-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Amazon EKS MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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805 Amazon EKS MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.