tech
April 2, 2026
Vibe Check: Opus 4.6—The Best Coding Model We’ve Tested (With Some Maddening Habits)
It one-shotted a problem other models missed—and brings agentic, parallel work to non-coding tasks
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TL;DR
- Opus 4.6 is the best AI coder tested, outperforming GPT-5.3 Codex and Opus 4.5 on a challenging iOS coding task.
- The model is more thorough, explores context more carefully, and is smarter than Opus 4.5, but is slower and more verbose.
- Opus 4.6 offers a more fluid drafting experience for writing and editing, applying editorial rules more consistently.
- It is Anthropic's most agentic model yet, driving tasks forward with less handholding through parallelization and autonomous actions.
- "Adaptive Thinking" replaces "Extended Thinking," adjusting reasoning based on task difficulty.
- Users report successes in shipping code fixes for complex iOS problems and appreciate the default parallelization for knowledge-work tasks.
- Despite improvements, Opus 4.6 can still make unexpected changes and exhibit 'AI-isms' in writing.
- The model's strengths include early scope locking, parallel threads by default, and adaptation to user intent.
- Weaknesses include wavering pace under load, uneven surface alignment in visual builds, and occasional signal haze.