Handles Mexican CFDI 4.0 invoice generation and SAT catalog lookups for AI agents working with local accounting workflows. You'd reach for this when building assistants that need to create compliant facturas or resolve tax codes without manual lookups. Access is controlled via API keys with granular permissions, and it runs over streamable HTTP rather than stdio. The underlying Notsy platform appears to focus on WhatsApp-based invoicing, so this MCP server essentially opens that compliance engine to Claude and other AI tools that need to interact with Mexico's tax authority systems programmatically.