We present our submission to Task 3 (Discourse Relation Classification) of the DISRPT 2025 shared task. Task 3 introduces a unified set of 17 discourse relation labels across 39 corpora in 16 languages and six discourse frameworks, posing significant multilingual and cross‐formalism challenges. We first benchmark the task by fine‐tuning multilingual BERT‐based models (mBERT, XLM‐RoBERTa‐Base, and XLM‐RoBERTa‐Large) with two argument‐ordering strategies and progressive unfreezing ratios to establish strong baselines. We then evaluate prompt‐based large language models (namely Claude Opus 4.0) in zero‐shot and few‐shot settings to understand how LLMs respond to the newly proposed unified labels. Finally, we introduce HiDAC, a Hierarchical Dual‐Adapter Contrastive learning model. Results show that while larger transformer models achieve higher accuracy, the improvements are modest, and that unfreezing the top 75% of encoder layers yields performance comparable to full fine‐tuning while training far fewer parameters. Prompt‐based models lag significantly behind fine‐tuned transformers, and HiDAC achieves the highest overall accuracy (67.5%) while remaining more parameter‐efficient than full fine‐tuning.

This paper presents our approach to the PromiseEval task at SemEval-2025, which focuses on verifying promises in corporate ESG (Environmental, Social, and Governance) reports. We explore three model architectures to address the four subtasks of promise identification, supporting evidence assessment, clarity evaluation, and verification timing. Our first model utilizes ESG-BERT with task-specific classifier heads, while our second model enhances this architecture with linguistic features tailored for each subtask. Our third approach implements a combined subtask model with attention-based sequence pooling, transformer representations augmented with document metadata, and multi-objective learning. Experiments on the English portion of the ML-Promise dataset demonstrate progressive improvement across our models, with our combined subtask approach achieving a private leaderboard score of 0.5268, outperforming the provided baseline of 0.5227. Our work highlights the effectiveness of linguistic feature extraction, attention pooling, and multi-objective learning in promise verification tasks, despite challenges posed by class imbalance and limited training data.