Provide Generic Solutions To One-Time Problems

Do not build another agent testbed/simulator just because you can.
There are plenty of systems: FIPA-OS, JADE, ZEUS, NetLogo, etc.
You will probably not be able to re-use something if you built it for a specific applications (no matter how "generalized" you think you are being).
It takes a lot of effort to make something generalized.
One of the tenets of extreme programming is not to over-design. Build only what you need now.