The implementation of the Last Planner® System increases the reliability of planning and performance levels through the management of commitments. So far, the conversations during which commitments are set at planning meetings have not been analyzed in sufficient depth. However, this analysis is essential to generate reliable commitments that reduce the uncertainty and variability of projects. The research reported in this paper moves toward this analysis by developing indicators of commitments based on the Linguistic Action Perspective, developed by Fernando Flores. Indicators of commitments (i.e. definition of roles and responsibilities, declaration of the relevance of each commitment); requests and promises (i.e. making the deadline explicit); and foundations of trust (i.e. reliability), were developed and tested based on the methodology “Design Science Research”. To verify the feasibility of measuring these indicators, a pilot test was conducted, which consisted of a Villego® Simulation applied to a group of students. Given the nature of this simulation, only part of the indicators could be verified, while the remainder is currently being verified through observation on site. The indicators that were validated are a useful tool to measure, control and improve the management of commitments in planning meetings, as they provide fast and specific feedback on these aspects, which undoubtedly enriches implementation of the Last Planner® System.