AI is already building the next version of itself. Anthropic claims the majority of its code is now written by Claude Code. OpenAI says GPT-5.3-Codex helped build itself. This is called recursive self improvement and researchers have been talkingg about it since the 1960s. One researcher flagged a red line: when 99% of AI code is written by AI. His estimate for when we cross it? About now. want to go deeper 👇 📄 Original IEEE Spectrum piece on RSI >Google DeepMind's AlphaEvolve paper > Wikipedia's RSI page > Nathan Lambert on Lex Fridman #490 > AI Alignment Forum