ImproBR: Bug Report Improver Using LLMs

arXiv cs.AI / 4/30/2026

💬 OpinionDeveloper Stack & InfrastructureTools & Practical UsageModels & Research

Key Points

  • The paper introduces ImproBR, an LLM-based pipeline that automatically detects and rewrites low-quality bug reports by filling in missing or unclear sections for Steps to Reproduce (S2R), Observed Behavior (OB), and Expected Behavior (EB).
  • ImproBR uses a hybrid approach: a fine-tuned DistilBERT classifier, heuristic checks, and an LLM analyzer orchestrated with GPT-4o mini using section-specific few-shot prompts.
  • It further improves accuracy by applying Retrieval-Augmented Generation (RAG) backed by Minecraft Wiki domain knowledge.
  • In evaluations on Mojira (139 challenging real-world reports), ImproBR dramatically boosts structural completeness (7.9% to 96.4%), increases executable S2R (28.8% to 67.6%), and raises fully reproducible bug reports (1 to 13).
  • The results suggest that LLM-assisted bug triage can substantially reduce back-and-forth between users and developers and make reports actionable sooner.

Abstract

Bug tracking systems play a crucial role in software maintenance, yet developers frequently struggle with low-quality user-submitted reports that omit essential details such as Steps to Reproduce (S2R), Observed Behavior (OB), and Expected Behavior (EB). We propose ImproBR, an LLM-based pipeline that automatically detects and improves bug reports by addressing missing, incomplete, and ambiguous S2R, OB, and EB sections. ImproBR employs a hybrid detector combining fine-tuned DistilBERT, heuristic analysis, and an LLM analyzer, guided by GPT-4o mini with section-specific few-shot prompts and a Retrieval-Augmented Generation (RAG) pipeline grounded in Minecraft Wiki domain knowledge. Evaluated on Mojira, ImproBR improved structural completeness from 7.9% to 96.4%, more than doubled the proportion of executable S2R from 28.8% to 67.6%, and raised fully reproducible bug reports from 1 to 13 across 139 challenging real-world reports.