GLM-5.3

GLM-5.3 is positioned as a flagship open-weights model aimed squarely at complex coding and long-horizon agentic workloads. According to its release notes, every gain over the prior version comes from post-training, since GLM-5.3 shares the same base model as GLM-5.2 rather than retraining from scratch. The model is distributed under an MIT open-source license with no regional restrictions, and it is built to operate within a solid 1M-token context window, making it suited to repositories, documentation sets, and multi-step task chains that would overflow smaller context budgets.

On qualitative strengths, GLM-5.3 reports a 50% improvement over GLM-5.2 on an in-house code benchmark and claims open-source state-of-the-art results on Terminal Bench 3.0 and Agents' Last Exam. The post-training scaling also surfaced stronger cyber capabilities than expected, with the model reaching state-of-the-art performance on CyberGym for vulnerability discovery and more than doubling GLM-5.2 on exploitation benchmarks. These traits make GLM-5.3 a natural fit for developers and agent builders who want an open model that can sustain long, tool-using workflows and tackle difficult software-engineering problems, while a separate GLM-5.3-Flash variant delivers a hybrid sparse/linear-attention design for cost-sensitive deployments.