Currently harbormaster has the three status you can send it, pass, fail, and 'work'. From the documentation:
>'work' : Report that work on the target is ongoing. This message can be used to report partial results during a build.
The partial build results can only be in the form of 'lint' or 'unit' test results.
I think it is important to add the ability to update harbormaster with more information from external build systems, such as build progress, queue status, or any other arbitrary information. This could just go into the log.