OpenAI's GPT-5, as described by CEO Sam Altman, represents a significant leap in AI capabilities, claiming "PhD-level expert performance" across various fields. Unlike its predecessor GPT-4, which faced challenges in production environments despite impressive tests, GPT-5 employs a router-based architecture with multiple specialized submodels that dynamically handle queries based on complexity. This innovation promises improved response times and resource utilization for enterprise AI applications, with enhanced factual accuracy and reduced hallucinations. However, GPT-5's implementation presents unique challenges, such as unpredictability across use cases, potential data leaks, and difficulties in multi-agent workflows. The model's performance on standardized benchmarks shows strengths in reasoning, coding, and information retrieval, though it may falter on seemingly simple tasks. To address these issues and ensure reliability in production, platforms like Galileo offer comprehensive observability and evaluation tools tailored to GPT-5's advanced architecture.