Errors

Failures have category, message, retryable, and optional database_error metadata. The message is for diagnosis; clients should branch on the category and retryable flag.

Category	Meaning	Retry?
`invalid_request`	Required input is missing or malformed.	No; fix the request.
`invalid_cursor`	Cursor is malformed, expired, or does not match the request.	No; restart pagination.
`source_not_found`	Source ID is not configured.	No; discover or configure the source.
`unsupported_source_capability`	The source does not provide the requested capability.	No.
`schema_not_found`	Exact schema does not exist or is not visible.	No; rediscover.
`relation_not_found`	Exact table/view does not exist or is not visible.	No; rediscover.
`unsupported_relation_kind`	The selected relation kind cannot be queried by the adapter.	No.
`dataporch_access_denied`	DataPorch authorization denied the operation.	No.
`database_permission_denied`	The database user lacks permission.	No; change database grants.
`database_unavailable`	The database could not be reached or used.	Yes, after checking health.
`query_timeout`	The server-side query timeout elapsed.	Sometimes; prefer a narrower query.
`cancelled`	The caller cancelled the operation.	No; caller-controlled.
`internal`	Unexpected runtime failure.	No by default; inspect logs.

Database error details are bounded before being returned or logged. Do not treat the error message as a stable machine-readable API.