@mwaskom looks like there is no default value for fieldcoeff_file - thus it doesn't get extracted for the outputs dict unless explicitly specified since it's left Undefined

So remind me, to fix this I need to add genfile=True in the input spec and then add fieldcoeff_file to this list?

If fieldcoeff_file can always be created, just adding default=True should suffice. If not, then this is intended behavior, as I don't believe interfaces' outputs can be dependent on workflow connections with this current engine

By "can always be created" you mean can be created by an interface with only the mandatory inputs set?

How is the suffix determined with default=True? Is there an example Interface you can point me to?

By "can always be created" you mean can be created by an interface with only the mandatory inputs set?

Yes, that's a better way to say it 👍

How is the suffix determined with default=True? Is there an example Interface you can point me to?

By setting default=True, I believe it'll go down this path by default and automatically generate the file. The suffix is determined from a hardcoded dict filemap

@mwaskom is this all set?

No, it needs a PR, I just haven't had time for it.

i did like to help