Hands-on Comparison: GPT-5.6 Excels at Code Maintenance, Claude at Greenfield Coding
iskander · x · 2026-08-01
A developer shared a hands-on comparison of AI coding assistants. He noted that GPT-5.6 (Codex) performs better for maintaining and making gradual additions to existing codebases, while Claude is an 'absolute whiz' at greenfield one-shot coding. He added that the efficiency uplift in well-defined, standalone evaluations can be 20x-100x, but drops to around 2x or even less than 1x when working within large existing codebases.
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