OpenMythos vs Qwen3.6-35B-A3B

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 open-sourced Qwen3.6-35B-A3B on April 16, 2026 — a sparse Mixture-of-Experts model with 35 billion total parameters but only ~3 billion active per forward pass. That architectural trick is the whole story: you get near-frontier performance while consuming compute comparable to a 3B dense model. It's available under Apache 2.0 on Hugging Face and ModelScope. The model supports a 262K token context window (extensible to 1M with YaRN), multimodal inputs including text, images, and video, and is purpose-built for agentic coding workflows. On SWE-bench and Terminal-Bench it outperforms the much larger dense Qwen3.5-27B, matching Gemma4-31B on several benchmarks. RefCOCO visual grounding score hits 92.0 — some multimodal metrics reach Claude Sonnet 4.5 territory. Community reaction has been immediate: r/LocalLLaMA lit up with benchmarks showing it solving coding tasks that models with 10x the active parameters couldn't handle. The FP8 quantized variant runs comfortably on a single 24GB consumer GPU, making this the most capable locally-runnable coding agent most developers have ever had access to.