Hi
This is not possible, to see who added which fields. You can not change same file/contnet at a same time, it will be locked by the user.
Even SAP also does not maintain such log for sdk user, to see who added which fields.
for example: If member1 added a field in BO and saved and activate, you only can see last changed by Member1, then later Member2 came and deleted same field, then poperties shows Last changed by Member2. So chages are recorded at BO level not at fields level.
Even if you just type space without touching any syntax it will records as a changes on save of a file.
And I dont see this is as problem or feasible requirement for SDK tool to maintain such log. I think you should manage development among team.
As work arround you can save your local file( Solution folder YXXXX_) in seprate location after each development by individual developer, and in case of conflict you can check local files saved in seprate location.
Regards
Sunil