aws_ec2_stop_instance · AWS MCP Server MCP: Risk & Policy

WHAT IT DOES

What aws_ec2_stop_instance does on AWS MCP Server

AI agents invoke aws_ec2_stop_instance to trigger actions in AWS MCP Server. 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 aws_ec2_stop_instance needs a policy

Stopping an EC2 instance is an Execute action because it triggers an external operation (AWS API call) whose effects depend on which instance ID is provided as an argument. While reversible (unlike Destructive), it causes immediate infrastructure state changes with potential blast radius: service interruption, dependent workload failures, and operational disruption.

From the tool's definition Tool name 'aws_ec2_stop_instance' and description 'Stop an EC2 instance' indicate the tool triggers a state-changing operation on cloud infrastructure.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

aws_ec2_stop_instance Rate-limited

aws_ec2_stop_instance 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": {
    "aws_ec2_stop_instance": {
      "limits": [
        {
          "counter": "aws_ec2_stop_instance_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

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

FAQ

Questions about aws_ec2_stop_instance

What does the aws_ec2_stop_instance tool do? +

Stop an EC2 instance. It is categorised as a Execute tool in the AWS 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 aws_ec2_stop_instance? +

Register the AWS MCP Server MCP server in PolicyLayer and add a rule for aws_ec2_stop_instance: 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 MCP Server. Nothing to install.

What risk level is aws_ec2_stop_instance? +

aws_ec2_stop_instance is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit aws_ec2_stop_instance? +

Yes. Add a rate_limit block to the aws_ec2_stop_instance 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 aws_ec2_stop_instance completely? +

Set action: deny in the PolicyLayer policy for aws_ec2_stop_instance. 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 aws_ec2_stop_instance? +

aws_ec2_stop_instance is provided by the AWS MCP Server MCP server (lokimcpuniverse/aws-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.