Purpose: This document specifies the CLARA interfaces of the CLAR Truth Data Generator as shown in Figure 1. The solid bold arrows are defined in Table 1 and Table 2. The dashed arrows from the CLAR Coefficient Generator and Truth Database to the CLAR Data Space Generator indicate a feedback loop and are defined in the CLAR Data Space Generator ICE (Reference 1). The dashed arrow from the Truth Database to the CLAR Coefficient Generator is defined in the CLAR Coefficient Generator ICD (Reference 2).