Looking at https://circleci.com/docs/2.0/api-job-trigger/#section=jobs, it looks like it should be possible to define a job that is not referenced in the workflow, and then use the API to kick it off. If part of that job’s steps is to attach_workspace, which workspace does it pick? Or is that not supported for jobs that are kicked off via API?
The second. It won’t have workspace to attach because it’s not part of a workflow.