Low Risk

list_s3_buckets

Lists AWS S3 buckets with details such as region, creation date, and optionally access policies.

How to control list_s3_buckets ↓

What list_s3_buckets does on AWS Security MCP Server

AI agents call list_s3_buckets to retrieve information from AWS Security MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

Low Risk

Why list_s3_buckets needs a policy

This tool retrieves and queries information about S3 buckets without creating, modifying, deleting, or executing any operations. It is a straightforward inventory or discovery function. The optional inclusion of access policies in the listing is still informational/read-only. The blast radius is minimal—an agent with this tool can only see bucket metadata, not access bucket contents or modify configurations.

From the tool's definition Tool name 'list_s3_buckets' and description 'Lists AWS S3 buckets with details such as region, creation date, and optionally access policies' indicate data retrieval only.

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

How to control list_s3_buckets

PolicyLayer is an MCP gateway — it sits between your AI agents and AWS Security 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.

  1. Create a free account and register AWS Security MCP Server — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
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Related tools and policies

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Questions about list_s3_buckets

What does the list_s3_buckets tool do? +

Lists AWS S3 buckets with details such as region, creation date, and optionally access policies. It is categorised as a Read tool in the AWS Security MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_s3_buckets? +

Register the AWS Security 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 AWS Security 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 AWS Security MCP Server MCP server (skjortan23/aws-security-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 AWS Security MCP Server tool call.

Start from AWS Security MCP Server, 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.

5 AWS Security MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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