AI agents call get_list_size to retrieve information from Iterable MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries data (user count) from the Iterable platform with no side effects. It does not create, modify, delete, or execute operations. The operation is read-only and returns only an aggregate count, making it a straightforward Read category with low severity and low blast radius if misused.
From the tool's definition Tool name 'get_list_size' and description 'Get the count of users in a specific list' indicate a retrieval operation that returns metadata about an existing list without modification.
Documented attack patterns abuse exactly the kind of access get_list_size gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Iterable MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for get_list_size:
{
"version": "1",
"default": "deny",
"tools": {
"get_list_size": {}
}
}get_list_size is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get the count of users in a specific list. It is categorised as a Read tool in the Iterable MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Iterable MCP Server MCP server in PolicyLayer and add a rule for get_list_size: 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 Iterable MCP Server. Nothing to install.
get_list_size 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_list_size 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_list_size. 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_list_size is provided by the Iterable MCP Server MCP server (iterable/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Iterable 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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78 Iterable MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.