sam_local_invoke

THE RISK

High Risk

Why sam_local_invoke needs a policy

This tool triggers code execution (a Lambda function or serverless handler) via the SAM framework. The effects are dependent on what code is in the invoked function and what arguments are passed to it. This makes it an Execute category risk.

From the tool's definition Tool name 'sam_local_invoke' indicates invocation of AWS SAM (Serverless Application Model) functions locally. SAM is used to build, test, and deploy serverless applications.

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

POLICY

How to control sam_local_invoke

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

policy.json

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

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.

Create a free account and register Prometheus 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.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

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All 805 Prometheus MCP Server tools →

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Go deeper

High-risk tools in Prometheus MCP Server → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

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 Prometheus MCP Server 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 Prometheus MCP Server 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 Prometheus MCP Server. 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 Prometheus MCP Server MCP server (awslabs.prometheus-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 Prometheus MCP Server tool call.

Start from Prometheus 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 →