Though many computational tools are designed for high-resource languages, they can also benefit under-described and endangered languages. This is exemplified by our ongoing project on the description and documentation of Asama, an endangered language of Japan. We focus on the use of finite-state transducers to implement a grammar of verb morphology. This computational implementation enabled us to directly check the accuracy of our analysis, correct mistakes, and fill gaps in the description. These tools were also put to use for improving and speeding up the production of interlinear glossed texts with standard tools used by fieldworkers. Such tools also provide a straightforward mean to quantitatively explore the complexity of morphological systems