This work presents the idea and a prototype of workflow systems defined through constraints. We think that in many domain areas, such as health care, workflow systems are too inflexible. One does not know in advance what activities does the patient has to go through. Actually a new form of interaction with the workflow is needed, in which a controller asks the systems which precondition activities are necessary in order to execute a target activity and schedule the target activity. We also present Tucupi, a prototype of such constraint based WFMS.Este trabalho apresenta a ideia e um protótipo de sistemas de workflow definidos através de restrições. Pensamos que em muitas áreas de domínio, como assistência médica, os sistemas de fluxo de tra...