Lists custom audiences in a Meta ad account. Args: - ad_account_id (string): Ad account ID (e.g., act_123456789) - limit (number): Max results (1–100, default 20) - after (string, optional): Pagination cursor Returns audience names, types, size estimates, and delivery status.
AI agents call meta_list_custom_audiences to retrieve information from Meta MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a Read operation: it retrieves and queries audience data from Meta's ad account without any side effects or modifications. However, severity is elevated to 'medium' rather than 'low' because the returned data (audience names, types, sizes, delivery status) reveals sensitive business intelligence about targeting segments, customer lists, and campaign reach metrics that could be misused if an agent exfiltrates…
From the tool's definition Tool description states 'Lists custom audiences' and 'Returns audience names, types, size estimates, and delivery status' — these are query/retrieval operations with no modification or deletion of data.
Documented attack patterns abuse exactly the kind of access meta_list_custom_audiences gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Meta MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for meta_list_custom_audiences:
{
"version": "1",
"default": "deny",
"tools": {
"meta_list_custom_audiences": {}
}
}meta_list_custom_audiences is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Lists custom audiences in a Meta ad account. Args: - ad_account_id (string): Ad account ID (e.g., act_123456789) - limit (number): Max results (1–100, default 20) - after (string, optional): Pagination cursor Returns audience names, types, size estimates, and delivery status. It is categorised as a Read tool in the Meta MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Meta MCP Server MCP server in PolicyLayer and add a rule for meta_list_custom_audiences: 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 Meta MCP Server. Nothing to install.
meta_list_custom_audiences 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 meta_list_custom_audiences 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 meta_list_custom_audiences. 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.
meta_list_custom_audiences is provided by the Meta MCP Server MCP server (oliverames/meta-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Meta 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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200 Meta MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.