{"type":"analysis","id":"analysis:research-livenerf-finds-no-large-opus-5-5-drop-but-can-t-see-small-changes-model-swaps","slug":"research-livenerf-finds-no-large-opus-5-5-drop-but-can-t-see-small-changes-model-swaps","title":"LiveNerf finds no large Opus 5.5 drop, but can't see small changes, model swaps or coding agents","description":"A 34-day public benchmark rules out accuracy drops of roughly 6.6 points or more on a 78-question QA panel. Its own validation shows it cannot catch an Opus 5 substitution, and it never tests agentic coding.","published_at":"2026-11-09T21:00:00.000Z","updated_at":"2026-11-09T21:00:00.000Z","record_date":"2026-11-09","topics":["claude","claude_code","agents","research"],"source_urls":["https://blog.nathanlangley.dev/posts/livenerf-30-days.html","https://github.com/ninjahawk/livenerf/blob/main/docs/VALIDATION.md","https://github.com/ninjahawk/livenerf","https://github.com/ninjahawk/livenerf/blob/main/docs/DESIGN.md","https://www.anthropic.com/engineering/a-postmortem-of-three-recent-issues"],"language":"en","routes":{"html":"https://newruntime.com/analysis/research-livenerf-finds-no-large-opus-5-5-drop-but-can-t-see-small-changes-model-swaps/","markdown":"https://newruntime.com/analysis/research-livenerf-finds-no-large-opus-5-5-drop-but-can-t-see-small-changes-model-swaps.md","json":"https://newruntime.com/analysis/research-livenerf-finds-no-large-opus-5-5-drop-but-can-t-see-small-changes-model-swaps.json"},"author":{"role":"author","name":"Andrey Reshetnikov","profile":"https://newruntime.com/owner-profile.md","profile_json":"https://newruntime.com/owner-profile.json","same_as":["https://www.linkedin.com/in/reshetnikov1/","https://t.me/lapetuse"]},"editorial_provenance":{"desk":"authorial","target_ref":"deep_research:a477fcf3-fc4e-493b-9dd9-b7437589d85c","authorial_article_id":"a477fcf3-fc4e-493b-9dd9-b7437589d85c"},"next_reads":[{"type":"topic","path":"/topics/claude/","url":"https://newruntime.com/topics/claude/","title":"Claude","reason":"Explore the claude topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/claude.md","json_url":"https://newruntime.com/topics/claude.json"},{"type":"topic","path":"/topics/claude-code/","url":"https://newruntime.com/topics/claude-code/","title":"Claude Code","reason":"Explore the claude_code topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/claude-code.md","json_url":"https://newruntime.com/topics/claude-code.json"},{"type":"topic","path":"/topics/agents/","url":"https://newruntime.com/topics/agents/","title":"Agents","reason":"Explore the agents topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/agents.md","json_url":"https://newruntime.com/topics/agents.json"},{"type":"collection","path":"/analysis/","url":"https://newruntime.com/analysis/","title":"Analysis","reason":"Open the latest authorial analysis.","media_type":"text/html","json_url":"https://newruntime.com/analysis.json"},{"type":"collection","path":"/sources/","url":"https://newruntime.com/sources/","title":"Sources","reason":"See the original sources this archive cites.","media_type":"text/html"}]}