Why AI Tools Are Moving to Rust

Is Rust actually replacing Python, or is something deeper happening under the hood? In this deep dive, we investigate why AI tools are migrating to Rust, debunk the myths around government mandates and Elon Musk's tweets, explore how PyO3 lets Rust code escape the Python GIL, and uncover the four hidden costs driving this shift. What's inside: • The Reality: Why Rust is moving in underneath Python packages rather than replacing the language you type. • Hype vs. Fact: Checking the claims behind Elon's tweets and why US federal memory-safety guidance actually lists Python as safe. • Escaping the GIL: How PyO3's py.detach lets Rust drop Python's Global Interpreter Lock and saturate every CPU core. • The 4 Hidden Costs: Hot validation loops (Pydantic), runtime dependencies (uv and Codex CLI), unsafe pickle files (safetensors), and garbage-collection pauses. • The CPython Twist: Why Python core developers proposed introducing optional Rust into Python 3.16 itself. • The Actionable Takeaway: Why app developers should stay in Python, and the two setup fixes you should make today. ⏱️ Chapters: 0:00 You're Already Running Rust in Python 1:22 Debunking the Elon & US Mandate Hype 2:34 Why Tooling Moved: Ruff & uv 3:18 How PyO3 Escapes the Python GIL 4:39 The 4 Reasons AI Plumbing Chose Rust 5:55 Safetensors vs. The Pickle Security Trap 7:47 Rust Inside CPython Itself (Python 3.16) 9:13 Final Verdict: Do You Need to Learn Rust? 🔗 Sources & Documentation: • OpenAI Codex CLI Migration to Rust: https://github.com/openai/codex/discussions/1174 • Astral Announcement - Launching uv: https://astral.sh/blog/uv • uv Caching & Hardlink Documentation: https://docs.astral.sh/uv/concepts/cache/ • PyO3 Parallelism & GIL Detach Guide: https://pyo3.rs/main/parallelism.html • Python Free-Threading Documentation: https://docs.python.org/3/howto/free-threading-python.html • Pydantic V2 Architecture & Rust Core: https://pydantic.dev/articles/pydantic-v2 • Hugging Face Safetensors Security Audit: https://huggingface.co/blog/safetensors-security-audit • CISA Memory-Safe Roadmaps Guidance: https://www.cisa.gov/news-events/news/cisa-nsa-fbi-and-international-cybersecurity-authorities-publish-guide-case-memory-safe-roadmaps • Python Language Summit - Rust for CPython: https://blog.python.org/2026/09/language-summit-2026-rust-for-cpython/ 🔔 Subscribe: https://www.youtube.com/channel/UC0DZj1PNa_Fp0MU6uPSKv5w?sub_confirmation=1 💙 Become a Member: https://www.youtube.com/channel/UC0DZj1PNa_Fp0MU6uPSKv5w/join 🐦 Twitter/X: https://x.com/cloud_codes 💬 Discord: https://discord.gg/mhgXXmhrh #rust #python #ai #softwareengineering #machinelearning #programming #openai #cloudcodes