MiMo-V2.5-Pro vs OpenMythos

MiMo-V2.5-Pro is Xiaomi's latest and most capable AI model, released April 22, 2026. It combines a 1-million-token context window with multimodal capabilities — vision, audio, and text — in a single agent-ready model. On SWE-bench Pro, it resolves 57.2% of tasks, placing it near the top tier alongside GPT-5.4 and Claude Opus 4.6. What's genuinely surprising isn't the benchmark score — it's the efficiency. MiMo-V2.5-Pro uses roughly 42% fewer tokens than Kimi K2.6 at equivalent benchmark scores, and about 40–60% fewer tokens than comparable frontier models on ClawEval trajectories. That translates directly to lower API costs: the model is priced at approximately $1 per million input tokens. Xiaomi is best known for smartphones and consumer hardware, and MiMo represents a serious pivot into AI services. The company has been quietly building foundation model capabilities for two years, and MiMo-V2.5-Pro is the clearest signal yet that consumer hardware companies won't sit on the sidelines of the foundation model race.

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.