Its main features are dynamic configurability and programmability via a language based on GNU Guile and the embedded arithmetic Cassowary constraint solver.

The primary developers were Greg Badros and Maciej Stachowiak.

The constraint solver is used to constrain window behavior.

In real time, the Cassowary constraint solver re-solves the system of equalities and inequalities and applies the new mathematical solution to the on-screen layout, animating windows to their new positions.

[1] Scwm development has been stagnant since 2000 when Badros completed his Ph.D. at the University of Washington; the last updates to the git repository have focused on maintaining compatibility with Guile 2.0.x.