list_length

THE RISK

Low Risk

Why list_length needs a policy

This tool performs a retrieval operation to obtain information (the length/count of a list) with no side effects, no data modification, no code execution, and no destructive actions. It is purely informational, classifying it as a Read operation with low severity since the blast radius of misuse is minimal.

From the tool's definition Tool name 'list_length' and description 'Get length of list' indicate a query operation that retrieves metadata about a list without modifying or executing operations.

Documented attack patterns abuse exactly the kind of access list_length gives an agent:

POLICY

How to control list_length

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 list_length:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_length": {}
  }
}

list_length is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Amazon EKS MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Amazon EKS MCP Server tools

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All 805 Amazon EKS MCP Server tools →

Read tools on other servers

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Go deeper

Roll out MCP under one policy → Per-person scoped tokens, one central policy, and full audit across every server your team connects.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →
PolicyLayer vs alternatives → How deterministic, per-call MCP policy compares with gateways, identity layers, and authorisation platforms.

FAQ

Questions about list_length

What does the list_length tool do? +

Get length of list. It is categorised as a Read tool in the Amazon EKS MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_length? +

Register the Amazon EKS MCP Server MCP server in PolicyLayer and add a rule for list_length: 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.

What risk level is list_length? +

list_length is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_length? +

Yes. Add a rate_limit block to the list_length 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.

How do I block list_length completely? +

Set action: deny in the PolicyLayer policy for list_length. 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.

What MCP server provides list_length? +

list_length 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.

Enforce policy on every Amazon EKS MCP Server tool call.

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.

CHECK YOUR STACK →