Opus 1M Tokens: 22% Loss Nobody Talks About

Original author：Rodrigo Rahman

Original source：https://www.youtube.com/embed/oLnawLwdlkU

Hey dev, did you know that Opus drops from 91.9% to 78.3% accuracy when you fill the context window? That's a 22% drop. And the other models are WORSE — GPT 5.4 only hits 36%, Sonnet 4.5 only 18%. In this video I show with real data why throwing the entire codebase at AI is a trap. Bad code, technical debt, all of this comes together and contaminates the result. The solution? Decompose into tasks of ~200K tokens using SDD (Spec Driven Development). Stop falling for marketing 1 million tokens and start using AI the right way. ⏱️ TIMESTAMPS 00:00 — Opus 1M tokens: does it make a difference? 01:30 — AI Code Experience (free event) 02:30 — What is token and context window 04:30 — What we gained with 1M tokens 06:00 — Why the entire codebase in the window is a trap 08:00 — Context Degradation: the Long Context Retrieval benchmark 10:00 — Opus 91.9% → 78.3% (22% loss) 12:00 — Comparison: GPT 36%, Sonnet 4.5 18%, Sonnet 4.6 65% 13:30 — SDD and decomposition into smaller tasks 16:00 — Warning: don't fall for token marketing ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 🔥 FREE EVENT: AI CODE EXPERIENCE 30, 31 March and April 1st — live! Learn how to use AI in development efficiently. 👉 Sign up: http://aicodingexperience.com.br/ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 🤖 AI ACADEMY Learn AI applied to dev in practice — real projects, without the hassle. 👉 https://academiadasias.com.br/ 🎓 FLUTTER ACADEMY Complete Flutter and Dart course — from zero to advanced. 👉 https://novo.academiadoflutter.com.br/ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 📱 ME FOLLOW ON NETWORKS Instagram: https://www.instagram.com/rodrigorahman.dev/ LinkedIn: https://www.linkedin.com/in/rodrigo-rahman/ Twitter/X: https://twitter.com/rodrigorahman GitHub: https://github.com/rodrigorahman #ia #programacao #desenvolvimento #flutter #dart #claude #opus #chatgpt #sdd #vibe-coding