It was noted on IRC that the search engine has no way of telling the client "hey I screwed up" after StartSearch(s) has been invoked. The reasons for this could be many - OOM, non-fatal bug, full moon, etc. Currently the only real solution is to emit SearchDone and let the client wonder why it only received 0 hits. There are two alternatives : 1) Introduce a new signal SearchFailed(s: search_handle, i: error_code, s: message). This will be the  API compatible solution 2) Add a new value to the SearchDone signal, changing signature to SearchDone (s: search_handle, i: exit_code, s: message). This will break API however I hate 2) because it (doh) it breaks API. I love 2) because it will fit much better in to my control flow logic. I am more or less indifferent on 1) - it is not very clean IMHO, but it is API stable. Status quo could be acceptable to me, but I think it could be a good idea to make better room for handling of bugs. After all Xesam is an all new technology we are pusing in. 2 gets my vote. I am very much willing to reconsider if people are massively annoyed by this (small) API change. Please chime in! Cheers, Mikkel