GLM-5 vs. Claude Mythos 5.1

GLM-5 is Z.ai’s most advanced open-source model to date, purpose-built for complex systems engineering, long-horizon planning, and autonomous agent workflows. Building on the foundation of GLM-4.5, it dramatically scales both total parameters and pre-training data while increasing active parameter efficiency. The integration of DeepSeek Sparse Attention allows GLM-5 to maintain strong long-context reasoning capabilities while reducing deployment costs. To improve post-training performance, Z.ai developed slime, an asynchronous reinforcement learning infrastructure that significantly boosts training throughput and iteration speed. As a result, GLM-5 achieves top-tier performance among open-source models across reasoning, coding, and general agent benchmarks. It demonstrates exceptional strength in long-term operational simulations, including leading results on Vending Bench 2, where it manages a year-long simulated business with strong financial outcomes. In coding evaluations such as SWE-bench and Terminal-Bench 2.0, GLM-5 delivers competitive results that narrow the gap with proprietary frontier systems. The model is fully open-sourced under the MIT License and available through Hugging Face, ModelScope, and Z.ai’s developer platforms. Developers can deploy GLM-5 locally using inference frameworks like vLLM and SGLang, including support for non-NVIDIA hardware through optimization and quantization techniques. Through Z.ai, users can access both Chat Mode for fast interactions and Agent Mode for tool-augmented, multi-step task execution. GLM-5 also enables structured document generation, producing ready-to-use .docx, .pdf, and .xlsx files for business and academic workflows. With compatibility across coding agents and cross-application automation frameworks, GLM-5 moves foundation models from conversational assistants toward full-scale work engines.

Claude Mythos 5.1 signifies the latest evolution in the Mythos series of models developed by Anthropic, specifically designed for advanced applications across fields such as cybersecurity, biology, scientific research, programming, and extensive knowledge-intensive tasks. Although it is built on the same core architecture as Claude Fable 5.1, it stands out due to its distinct safety protocols: while Fable 5.1 is broadly available, Mythos 5.1 is restricted to select trusted access initiatives that incorporate specialized safeguards for cybersecurity and life sciences. This model sets a new standard for performance in autonomous coding and exhibits unmatched cyber capabilities compared to all previous Anthropic models. In the scientific research domain, Mythos 5.1 adeptly manages specialized tools and complex workflows related to molecular design, computational biology, and other technical disciplines. During Anthropic's evaluation, it successfully designed high-affinity protein binders for various targets, achieving its highest hit rate to date. Furthermore, it excelled in optimizing seven distinct open-source deep learning models that focus on protein and genomics. By advancing the limits of what can be accomplished, Mythos 5.1 is poised to play a pivotal role in shaping future research and development projects, ultimately influencing a wide array of scientific inquiries and technological innovations. Its capabilities suggest a transformative impact on how complex biological and computational problems are approached in the coming years.