Best LLM for Coding by Task in 2026: A Decision Matrix Across 10 Real Sub-Tasks

TL;DR — There is no single best coding LLM in 2026. Across ten sub-tasks we mapped, Claude Opus 4.6 still leads cross-file refactoring and long-context comprehension; GPT-5.5 wins greenfield scaffolding and structured tool use; Gemini 3.1 Pro handles...