[mikece]

If the idea is to have output from CLI apps/scripts that can be easily parsed so that chaining scripts together without regexing yourself to death is the goal this sounds like what PowerShell Core (which runs on macOS and Linux as well) does: PS commands return objects -- with a default .ToString() output if you don't grab the result and use it in the next step/script -- allowing easy object.property accessors as well as foreach iteration if the command returns a list/array of objects.

[zeisss]

I understand the idea for fetching / listing resources, e.g. list me all ec2 machines.

My confusion is more about general logs ("preparing output in /tmp/randomid") and progress updates ("the job is 25% done", "deploying cluster", "docker image download: 90%"). Is that actually of interest as structured output or should that remain as human readable on stderr?