OpenMythos vs Qwen3 Family

OpenMythos is a community-driven theoretical reconstruction of Claude Mythos's suspected architecture, implementing a Recurrent-Depth Transformer (RDT) — a looped transformer that recycles layers multiple times per forward pass for deeper reasoning without massive parameter growth. The project drew 10,100 GitHub stars in its first week, reflecting intense developer curiosity about what's powering Anthropic's latest generation models. The architecture has three stages: a Prelude (initial layers), a Recurrent Block (looped up to 32 times with shared weights), and a Coda (final layers). Rather than stacking hundreds of unique layers, the recurrent block runs the same weights multiple times with learned injection parameters updating hidden states between loops — enabling implicit chain-of-thought reasoning in continuous latent space without generating intermediate tokens. The project supports Grouped Query Attention (GQA) with optional Flash Attention 2, Multi-Latent Attention (MLA), and sparse MoE with routed and shared experts. Model scales range from 1B to 1T parameters. The key claim is that RDT achieves reasoning depth comparable to fixed-depth models with far more parameters, since computational complexity scales with loop iterations rather than layer count. This would explain how Claude Mythos achieves strong reasoning performance without the extreme parameter counts of brute-force scaling — though Anthropic has neither confirmed nor denied the architecture.

Alibaba's Qwen team released the full Qwen3 model family this week — 8 models ranging from 0.6B to 235B parameters, spanning both dense and Mixture-of-Experts (MoE) architectures. The headline model is Qwen3-235B-A22B, a 235B MoE that activates 22B parameters per token and matches GPT-4.1 on coding and math benchmarks while running at a fraction of the cost. All Qwen3 models feature switchable "thinking modes" — a built-in chain-of-thought toggle that can be enabled or disabled per request. This eliminates the need for separate reasoning vs. instruct variants, letting developers trade latency for accuracy dynamically. All models are released under Apache 2.0, with weights available on Hugging Face and ModelScope. The smaller models are competitive at their size class: Qwen3-4B reportedly matches Qwen2.5-72B-Instruct on several benchmarks, and the 0.6B model is designed to run efficiently on embedded and edge devices. The release also introduces a new multilingual benchmark covering 119 languages, on which the Qwen3 family sets new state-of-the-art scores for open-weights models.