AI agents call list_cards to retrieve information from Mcp Afip without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns a list of registered cards without creating, modifying, deleting, or executing any actions. It is a straightforward read operation that retrieves data from the AFIP system. While card information is sensitive financial data, the tool itself only reads and does not perform transactions or commit financial obligations, keeping it in the Read category at low severity.
From the tool's definition Tool name 'list_cards' and description 'List registered cards' indicate a retrieval operation with no modification or side effects.
Documented attack patterns abuse exactly the kind of access list_cards gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Afip, and nothing reaches the server without passing your rules. This is the rule we recommend for list_cards:
{
"version": "1",
"default": "deny",
"tools": {
"list_cards": {}
}
}list_cards is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List registered cards. It is categorised as a Read tool in the Mcp Afip MCP Server, which means it retrieves data without modifying state.
Register the Mcp Afip MCP server in PolicyLayer and add a rule for list_cards: 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 Mcp Afip. Nothing to install.
list_cards 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_cards 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_cards. 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_cards is provided by the Mcp Afip MCP server (codespar/mcp-dev-latam). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Afip, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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1300 Mcp Afip tools catalogued and risk-classified — across an index of 43,000+ MCP servers.