Low Risk

client_list

Get a list of connected clients to the Valkey server.

How to control client_list ↓

What client_list does on Amazon Data Processing MCP Server

AI agents call client_list to retrieve information from Amazon Data Processing 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 client_list needs a policy

This tool performs a read-only operation to retrieve metadata about connected clients. It has no side effects, does not modify data, and poses minimal security risk. The only potential concern would be information disclosure if client metadata reveals sensitive connection details, but this is typically low-severity within an AWS data processing context.

From the tool's definition Tool name 'client_list' and description 'Get a list of connected clients to the Valkey server' indicate a query operation that retrieves information without modifying state.

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

How to control client_list

PolicyLayer is an MCP gateway — it sits between your AI agents and Amazon Data Processing MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for client_list:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "client_list": {}
  }
}

client_list 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 Amazon Data Processing 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 client_list

What does the client_list tool do? +

Get a list of connected clients to the Valkey server. It is categorised as a Read tool in the Amazon Data Processing MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on client_list? +

Register the Amazon Data Processing MCP Server MCP server in PolicyLayer and add a rule for client_list: 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 Data Processing MCP Server. Nothing to install.

What risk level is client_list? +

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

Can I rate-limit client_list? +

Yes. Add a rate_limit block to the client_list 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 client_list completely? +

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

client_list is provided by the Amazon Data Processing MCP Server MCP server (awslabs.aws-dataprocessing-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 Data Processing MCP Server tool call.

Start from Amazon Data Processing 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.

805 Amazon Data Processing MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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