create_function · Awslabs Valkey MCP: Risk & Policy

WHAT IT DOES

What create_function does on Awslabs Valkey

AI agents use create_function to create or update resources in Awslabs Valkey — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Awslabs Valkey environment.

WHY IT NEEDS A POLICY

Why create_function needs a policy

The name 'create_function' strongly implies creating a new resource (a function/script) in a Valkey/Redis-like data store. Creation is a Write operation. However, since the description is empty, there is uncertainty — it could potentially Execute code depending on implementation. Defaulting to Write given the 'create' prefix, but confidence is lowered due to lack of description.

From the tool's definition Tool name: create_function — description is empty/uninformative

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_function Rate-limited

create_function stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_function": {
      "limits": [
        {
          "counter": "create_function_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Awslabs Valkey, so you can run agents against it safely.

FAQ

Questions about create_function

What does the create_function tool do? +

create_function. It is categorised as a Write tool in the Awslabs Valkey MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_function? +

Register the Awslabs Valkey MCP server in PolicyLayer and add a rule for create_function: 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 Awslabs Valkey. Nothing to install.

What risk level is create_function? +

create_function is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit create_function? +

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

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

create_function is provided by the Awslabs Valkey MCP server (awslabs.valkey-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.