List EC2 instances
AI agents call aws_ec2_list_instances to retrieve information from AWS MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only operation to enumerate EC2 instances. It has no side effects, cannot modify or delete resources, and returns information only. Even in a multi-tenant AWS environment, listing instances reveals metadata but does not grant unauthorized access to instance internals or enable lateral movement without additional exploitation.
From the tool's definition Tool name contains 'list' and description states 'List EC2 instances' — a query operation that retrieves but does not modify infrastructure state.
Attacks that exploit this kind of access
List EC2 instances. It is categorised as a Read tool in the AWS MCP Server MCP Server, which means it retrieves data without modifying state.
Register the AWS MCP Server MCP server in PolicyLayer and add a rule for aws_ec2_list_instances: 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.
aws_ec2_list_instances is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the aws_ec2_list_instances 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.
Set action: deny in the PolicyLayer policy for aws_ec2_list_instances. 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.
aws_ec2_list_instances 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.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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