handle-cross-client-requests

Whenever a request spans multiple customers/clients/tenants/accounts at once (non-exhaustive list of phrasings — "across all clients", "which of our customers have the most X", "compare Y across the book of business", "totals across every tenant") against an MCP server whose data tools are scoped to answer for only ONE customer per call, draft the single-customer request once, enumerate the actual customers in scope, run it per customer, and aggregate the results yourself — do not answer from one customer's data, and do not query the whole org when the user named a subset.