AI agents call get_roles_for_service to retrieve information from Prometheus MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool appears designed to fetch or list IAM roles associated with a given service. This is a read-only query operation with no apparent side effects, data modification, or destructive capability. The low severity reflects that retrieving role information, while potentially sensitive, does not directly modify infrastructure or incur financial impact.
From the tool's definition Tool name 'get_roles_for_service' indicates retrieval of role information associated with a service. No description provided, but the naming pattern and context (AWS Managed Prometheus MCP server) suggests a query operation that retrieves existing IAM role…
Documented attack patterns abuse exactly the kind of access get_roles_for_service gives an agent:
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 get_roles_for_service:
{
"version": "1",
"default": "deny",
"tools": {
"get_roles_for_service": {}
}
}get_roles_for_service is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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get_roles_for_service. It is categorised as a Read tool in the Prometheus MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Prometheus MCP Server MCP server in PolicyLayer and add a rule for get_roles_for_service: 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.
get_roles_for_service 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 get_roles_for_service 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 get_roles_for_service. 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.
get_roles_for_service 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.
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.
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805 Prometheus MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.