I updated Eclipse with the new SDK tools (rev. 23), but now when Eclipse starts I receive the error:
This Android SDK requires Android Developer Toolk
WARNING
There is now an update for ADT 23.0.1, but the Windows and Linux scripts are messed up, so wait with the upgrade!
You could check for example tools/proguard/bin/*.sh in http://dl.google.com/android/android-sdk_r23.0.1-windows.zip.