sam_local_invoke · Awslabs Valkey MCP: Risk & Policy

WHAT IT DOES

What sam_local_invoke does on Awslabs Valkey

AI agents invoke sam_local_invoke to trigger actions in Awslabs Valkey. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why sam_local_invoke needs a policy

Although the description is empty (lowering confidence slightly), the tool name strongly indicates code execution capability. SAM local invoke runs serverless functions with arguments supplied by the user, making side effects dependent on the function implementation. This fits the Execute category—it triggers external operations (function execution) whose outcomes depend on provided arguments.

From the tool's definition Tool name 'sam_local_invoke' indicates invocation of AWS SAM (Serverless Application Model) functions locally. The 'invoke' verb combined with SAM context suggests execution of application code or Lambda functions.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

sam_local_invoke Rate-limited

sam_local_invoke stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "sam_local_invoke": {
      "limits": [
        {
          "counter": "sam_local_invoke_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-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 sam_local_invoke

What does the sam_local_invoke tool do? +

sam_local_invoke. It is categorised as a Execute tool in the Awslabs Valkey MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on sam_local_invoke? +

Register the Awslabs Valkey MCP server in PolicyLayer and add a rule for sam_local_invoke: 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 sam_local_invoke? +

sam_local_invoke is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit sam_local_invoke? +

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

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

sam_local_invoke 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.