OpenAI GPT-5.2 Codex vs. Gemini 3 Pro vs. Opus 4.5: Coding comparison (www.tensorlake.ai)

A recent comparison of three leading coding AI models—OpenAI's GPT-5.2 Codex, Google’s Gemini 3 Pro, and Anthropic's Opus 4.5—has drawn attention in the tech community as developers seek the best tools for their coding needs. The tests revealed that Gemini 3 Pro excelled in UI tasks, creating a superior 3D Minecraft implementation, but struggled with complex coding problems like LeetCode challenges, while GPT-5.2 Codex emerged as the most consistent overall performer, successfully addressing LeetCode solutions but hitting time limits on larger cases. Conversely, Opus 4.5 garnered criticism for its poor performance in UI tasks and subpar coding results, raising concerns about its viability and value in practical applications. These comparative results are significant for the AI/ML community as they showcase the varying capabilities of current models, emphasizing that while some excel in specific areas like frontend development, others may not justify their pricing. With context windows of 200K for Opus 4.5, 1M for Gemini 3 Pro, and 400K for GPT-5.2 Codex, understanding these metrics and performance results can guide developers in selecting the right AI model for their projects. As the development landscape rapidly evolves, the findings underscore the need for continued evaluation and adaptation to emerging technologies in coding assistant tools.