Beyond Static Prompts: Building Scale-Proof, Polymorphic Multi-Agent Systems with Google’s ADK

// Example: Centralized Schema Descriptor JSON { “domain”: “travel_expense”, “fields”: { “amount”: { “type”: “float”, “description”: “Total transaction amount in local currency”, “validation_hook”: “check_positive_bounds” }, “receipt_id”: { “type”: “string”, “description”: “Alphanumeric system ID found on the receipt image”, “validation_hook”: “regex_match_expense_v2” } } }