{"slug": "is-opus-5-5-nerfed-thinking-patterns-changed-on-november-3", "title": "Is Opus 5.5 nerfed? Thinking patterns changed on November 3", "summary": "Shane Melaugh reported on X that an analysis of 1,400 Claude Code sessions by Gemini 4 Argon found the reasoning behavior of Opus 5.5 changed sharply on November 3 even though the model name stayed the same. In a quick test on a real bug, Melaugh said Opus 5.5 at high effort jumped into action too quickly and failed to find a fix after 3 full hours, while Opus 5.5 at xhigh effort paused to think and found a fix within a few minutes. Melaugh said he launched a job on bb-1 using Opus 5.5 xhigh to check the claims against his cliproxy logs in ClickHouse.", "body_md": "Shane Melaugh on X: \"is Opus 5.5 nerfed?\nI just had Gemini 4 Argon analyze 1,400 Claude Code sessions and it found that on November 3, something definitely happened.\nthe model name didn't change, but the way it does reasoning took a sharp turn.\"\n\nis Opus 5.5 nerfed?\nI just had Gemini 4 Argon analyze 1,400 Claude Code sessions and it found that on November 3, something definitely happened.\nthe model name didn't change, but the way it does reasoning took a sharp turn.\n\nis Opus 5.5 nerfed?\nI just had Gemini 4 Argon analyze 1,400 Claude Code sessions and it found that on November 3, something definitely happened.\nthe model name didn't change, but the way it does reasoning took a sharp turn.\n\nquick test on a real bug showed Opus 5.5 high jumping into action too quickly, getting confused and being unable to find a fix after 3 full hours.\nmeanwhile Opus 5.5 xhigh takes a moment to think, finds a fix after a few minutes.\n\n@bot kick off a job in the fleet repo on bb-1 using opus 5.5 xhigh to investigate this for me. Curious how accurate the claims are. Dig through my cliproxy logs in clickhouse to see if things changed", "url": "https://wpnews.pro/news/is-opus-5-5-nerfed-thinking-patterns-changed-on-november-3", "canonical_source": "https://twitter.com/shanemelaugh/status/2119192075505893695", "published_at": "2026-11-09 07:04:25+00:00", "updated_at": "2026-11-09 07:20:48.108476+00:00", "lang": "en", "topics": ["large-language-models", "artificial-intelligence", "ai-research"], "entities": ["Shane Melaugh", "Opus 5.5", "Gemini 4 Argon", "Claude Code", "ClickHouse", "X"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/is-opus-5-5-nerfed-thinking-patterns-changed-on-november-3", "markdown": "https://wpnews.pro/news/is-opus-5-5-nerfed-thinking-patterns-changed-on-november-3.md", "text": "https://wpnews.pro/news/is-opus-5-5-nerfed-thinking-patterns-changed-on-november-3.txt", "jsonld": "https://wpnews.pro/news/is-opus-5-5-nerfed-thinking-patterns-changed-on-november-3.jsonld"}}