list_s3_buckets

THE RISK

Low Risk

Why list_s3_buckets needs a policy

This tool retrieves information about S3 buckets (a read operation) without creating, modifying, deleting, or executing anything. The blast radius is low since listing buckets reveals only metadata about resources the caller already has permissions to access; no side effects occur from calling this tool.

From the tool's definition Tool name 'list_s3_buckets' indicates a listing/enumeration operation. The description is empty, but the name strongly suggests querying S3 bucket metadata without modification.

Documented attack patterns abuse exactly the kind of access list_s3_buckets gives an agent:

POLICY

How to control list_s3_buckets

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_s3_buckets:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_s3_buckets": {}
  }
}

list_s3_buckets 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

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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_s3_buckets

What does the list_s3_buckets tool do? +

list_s3_buckets. 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_s3_buckets? +

Register the Amazon EKS MCP Server MCP server in PolicyLayer and add a rule for list_s3_buckets: 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_s3_buckets? +

list_s3_buckets is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_s3_buckets? +

Yes. Add a rate_limit block to the list_s3_buckets 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_s3_buckets completely? +

Set action: deny in the PolicyLayer policy for list_s3_buckets. 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_s3_buckets? +

list_s3_buckets 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 →