Add seed to DB via webservice (via Browser Extension/Rich Client)

To give everybody the possibility to collect seeds without knowing the netarchivsuite it would be very useful to have a Browser Extension which helps the user to collect URLs. There are many options to make such an GUI. To transmit the seeds this GUI needs to communicate with the NAS. The idea now is to have webservices which can be called by the extension.
One method would provide the HarvestDefintions which could be used by the user to select the definition for the collected seeds:
String[] getHarvestDefinitions()
After selecting among the collected seeds the user would submit the selected seeds by using another method:
void putSeedsForHarvestDefinitions(String definitionName, String[] seeds)
The design of these methods is just an first idea. Maybe other methods make more sense but I think it would be cool to have an API that can be called from external applications.