{"type":"analysis","id":"analysis:research-redwood-s-nls-depth-is-a-well-defined-architecture-metric-but-no-one-has-yet","slug":"research-redwood-s-nls-depth-is-a-well-defined-architecture-metric-but-no-one-has-yet","title":"Redwood's \"NLS depth\" is a well-defined architecture metric, but no one has yet shown that it predicts chain-of-thought monitorability","description":"Redwood Research builds on DeepMind's \"opaque serial depth\" to define a number that can be calculated for a model before training: how much reasoning it can chain together without writing anything out in readable text. The arithmetic carries over across open models. The link to how monitorable a model is in practice rests on one confounded example, GPT-6 Astra, and OpenAI disputes that architectur","published_at":"2026-10-22T20:00:00.000Z","updated_at":"2026-10-22T20:00:00.000Z","record_date":"2026-10-22","topics":["architecture","openai","design","research"],"source_urls":["https://blog.redwoodresearch.org/p/an-operationalization-of-opaque-serial","https://arxiv.org/abs/2603.09786","https://github.com/google-deepmind/serial_depth","https://deploymentsafety.openai.com/gpt-6-astra","https://techcrunch.com/2026/09/02/openais-new-reasoning-technique-alarms-ai-safety-experts/"],"language":"en","routes":{"html":"https://newruntime.com/analysis/research-redwood-s-nls-depth-is-a-well-defined-architecture-metric-but-no-one-has-yet/","markdown":"https://newruntime.com/analysis/research-redwood-s-nls-depth-is-a-well-defined-architecture-metric-but-no-one-has-yet.md","json":"https://newruntime.com/analysis/research-redwood-s-nls-depth-is-a-well-defined-architecture-metric-but-no-one-has-yet.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:a3d4048d-86c4-44c9-9f72-2703022f1c09","authorial_article_id":"a3d4048d-86c4-44c9-9f72-2703022f1c09"},"next_reads":[{"type":"topic","path":"/topics/architecture/","url":"https://newruntime.com/topics/architecture/","title":"Architecture","reason":"Explore the architecture topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/architecture.md","json_url":"https://newruntime.com/topics/architecture.json"},{"type":"topic","path":"/topics/openai/","url":"https://newruntime.com/topics/openai/","title":"Openai","reason":"Explore the openai topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/openai.md","json_url":"https://newruntime.com/topics/openai.json"},{"type":"topic","path":"/topics/design/","url":"https://newruntime.com/topics/design/","title":"Design","reason":"Explore the design topic hub.","media_type":"text/html","markdown_url":"https://newruntime.com/topics/design.md","json_url":"https://newruntime.com/topics/design.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":"/source-ledger.json","url":"https://newruntime.com/source-ledger.json","title":"Source Ledger","reason":"Inspect the public source evidence graph.","media_type":"application/json"}]}
