Development of software agents according to belief-desire-intention (BDI) model usually becomes challenging due to autonomy, distributedness, and openness of multi-agent systems (MAS). Hence, here, a domain-specific modelling language (DSML), called DSML4BDI, is introduced to support development of BDI agents. The syntax of the language provides the design of agent components required for the construction of the system according to the specifications of BDI architecture. The implementation of designed MAS on Jason BDI platform is also possible via model-to-text transformations built in the DSML. The comparative evaluation results showed that a significant amount of artefacts required for the exact MAS implementation can be automatically achieved by employing DSML4BDI. Moreover, time needed for developing a BDI agent system from scratch can be reduced to one-third in the case of using DSML4BDI. Finally, qualitative assessment, based on the developers' feedback, exposed how DSML4BDI facilitates development of BDI agents.