This dissertation's primary goal is to trouble the ableism embedded in how written communication is taught and evaluated. Drawing on principles of disability justice, user experience (UX) design, and socially just writing assessment theory, I develop equity-oriented approaches to classroom grading, writing program directed self-placement, and theories of validity. I argue that for writing assessment ecologies to continue moving toward the goals of justice and equity, including intersectional anti-ableism, there must be commitments to crip community building, flexibility as access, radical trust, and participatory localization