{ "error": { code, message, hint, docs } } with the matching HTTP status, whoever answered (the gateway or the data service). docs links to the code’s page here, https://docs.appgoat.ai/errors/<code>. Read hint: it says what to do next. Failed requests never cost credits.
param (the parameter at fault) on invalid_param and invalid_credentials, provider_status on provider_error, approve_url on forbidden.