Leanstral 1.5 vs. GLM-5

Leanstral 1.5 is a model under the Apache-2.0 license, crafted for proficient proof engineering within Lean 4, with the goal of improving both the functionality and accessibility of formal verification. This model features a remarkable total of 119 billion parameters, of which 6 billion are actively utilized, representing a major leap in efficiency for tasks related to theorem proving, agent-based proof engineering, and practical code verification. The evolution of Leanstral 1.5 included an extensive three-phase training regimen, which encompassed mid-training, supervised fine-tuning, and reinforcement learning through CISPO. In a multiturn environment, the model is designed to accept a theorem statement, propose a proof, and iteratively adjust its strategy based on input from the Lean compiler until the proof compiles successfully or resources run out. Operating in the code agent framework, Leanstral acts similarly to a developer navigating through a file system, enabling it to modify files, run bash commands, and engage with the Lean language server to track goals, errors, and type information in real time. This cutting-edge methodology not only simplifies the proof engineering workflow but also significantly enriches the overall user experience in formal verification tasks, making the process both more efficient and user-friendly. Furthermore, the integration of these capabilities positions Leanstral 1.5 as a transformative tool in the landscape of formal verification.

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.