The judge can influence the rules of civil procedure through case law and regulations. This research specifically examined how judges shape the Belgian rules of  civil procedure via case law. To this end, the explanatory value of three legal theoretical models — heteronomous, autonomous, and pragmatic legal reasoning — was studied. After outlining the characteristics of these models, the research analyzed several specific issues within civil procedural law. The aim was to determine the extent to which these models enhance the understanding and predictability of judicial decision-making and the resulting legal development. The analysis revealed that the pragmatic legal reasoning model offered the greatest explanatory value for the case law under review. Based on the characteristics of this model, the study identified three broader institutional features of how judges contribute to shaping the rules of civil procedure through case law in Belgian civil procedural law.