GPT-5: Key characteristics, pricing and model card

This article provides a comprehensive first-hand account of OpenAI's new GPT-5 model family, based on two weeks of preview access. The author details GPT-5's core characteristics, including its hybrid nature in ChatGPT and simpler API variants (regular, mini, nano) with adjustable reasoning levels. Key specifications like large token limits (272,000 input, 128,000 output) and multimodal input capabilities are highlighted. A significant focus is placed on GPT-5's aggressive pricing strategy, positioning it competitively against other leading models like Claude and Gemini, with a detailed comparison table. Insights from the GPT-5 system card reveal substantial improvements in reducing hallucinations, enhancing instruction following, and minimizing sycophancy, alongside the introduction of 'safe-completions' for nuanced safety responses. The article also critically examines the ongoing challenge of prompt injection, despite GPT-5 showing better resistance than predecessors. Finally, it explores API features such as 'thinking traces' and the 'reasoning_effort' option, concluding with practical examples like SVG generation benchmarks.