The UPSC assesses writing skills in the Mains exam through a series of essay-type questions and subject-specific papers. Candidates must demonstrate their ability to articulate thoughts clearly, structure arguments effectively, and maintain coherence. The evaluation focuses on the clarity of expression, logical flow, and relevance to the prompt. Additionally, writing techniques such as grammar and style are scrutinized. Effective responses often showcase the candidate's analytical capabilities and knowledge depth, indicating readiness for administrative roles.