Suppose you discovered that the MCP servers are returning sensitive columns such as credit card and category information to an element. How would you fix this architecturally?

Adopt a data‑masking or field‑level security strategy. Define Data Transfer Objects (DTOs) that include only the fields required by each consumer. Strip sensitive columns before serializing the response. Use an API gateway or middleware to enforce a schema that excludes protected fields. Store sensitive data encrypted at rest and decrypt only in the service that needs it, then immediately discard it. Implement role‑based access control so that only authorized services or users can request those fields. Add runtime validation to ensure no accidental leakage occurs. Finally, audit logs should capture any attempts to access or expose sensitive data, and automated tests should verify that responses do not contain prohibited fields.