It seems like we should have separate errors defined for this like "OperationNotSupportedByAgent" vs "OperationNotSupportedForTask" _Originally posted by @Tehsmash in https://github.com/a2aproject/A2A/pull/1160#discussion_r2485972562_ Investigate ExtendedAgentCardNotConfigured https://github.com/a2aproject/A2A/pull/1160#discussion_r2485983917