A configuration tool for a programmable HVAC controller is provided. The configuration tool may accept user input, and may generate a corresponding configuration profile based on the user input. The configuration profile may be downloaded to a programmable HVAC controller, which may, among other things, reconfigure the I/O terminals of the programmable HVAC controller. The configuration tool may generate a terminal diagram that labels at least some of the I/O terminals of the programmable HVAC controller based on the particular configuration profile. In some cases, the configuration tool may output the terminal diagram in a format that can be printed on a label, with the label being suitable for adhering to the programmable HVAC controller.