Redact columns

To hide columns whatever their values look like, add an allow policy rule with Redact columns, for example ssn,email,phone, scoped to the source. Matching values are replaced in the response.

It applies to MCP query results and HTTP JSON bodies, and follows columns through aliases (SELECT ssn AS tax_id is still redacted). It does not apply on the PostgreSQL wire, where only the PII scanner redacts.

If a column must never leave on any protocol, deny it instead: a source role deny statement on schema.table.column, or a policy deny rule with a Columns condition. See Redaction and PII.