AI agents call list_policies to retrieve information from AWS without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The 'list_policies' tool retrieves or enumerates IAM policies. Despite the empty description creating some ambiguity, the tool name itself is explicitly a 'list' operation, which is a read-only action with no modification or deletion of data. Context from sibling tools (attach_user_policy, attach_group_policy) confirms this is part of an IAM management suite.
From the tool's definition Tool name 'list_policies' and its AWS service context indicate a query operation. The naming convention follows standard AWS read patterns (list_*). No description provided to confirm side effects.
Documented attack patterns abuse exactly the kind of access list_policies gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and AWS, and nothing reaches the server without passing your rules. This is the rule we recommend for list_policies:
{
"version": "1",
"default": "deny",
"tools": {
"list_policies": {}
}
}list_policies is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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list_policies. It is categorised as a Read tool in the AWS MCP Server, which means it retrieves data without modifying state.
Register the AWS MCP server in PolicyLayer and add a rule for list_policies: 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. Nothing to install.
list_policies 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 list_policies 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 list_policies. 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.
list_policies is provided by the AWS MCP server (@awslabs/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from AWS, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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300 AWS tools catalogued and risk-classified — across an index of 43,000+ MCP servers.