GLM-5.1 vs OpenMythos

Z.ai (formerly Zhipu AI) has released GLM-5.1, a 754B-parameter Mixture-of-Experts model that's currently sitting at #1 on SWE-Bench Pro with a score of 58.4 — outperforming GPT-5.4 and Claude Opus 4.6 on long-horizon software engineering tasks. The model ships under MIT license with full weights on HuggingFace. GLM-5.1 was specifically designed for agentic software engineering workflows: multi-file reasoning, autonomous test-run-fix loops, and extended coding sessions that span hundreds of tool calls. It's not just a capability leap — at 754B active parameters via sparse MoE, it can be run more efficiently than a dense model of equivalent capability on a sufficiently provisioned cluster. The SWE-Bench Pro result is significant because that benchmark is harder to game than vanilla SWE-Bench Verified. It tests whether a model can resolve real GitHub issues with correct tests, proper diffs, and no regressions — the things that actually matter in production. For anyone running self-hosted coding agents or building on open models, GLM-5.1 just became the new baseline to beat.

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.