GLM 5.1

• 🧠 Next-generation flagship built for agentic engineering and long-horizon tasks.
• 🔧 Designed to keep using tools across extended autonomous runs.
• 🏢 Built by Z.ai (formerly Zhipu AI), released under MIT license.
• 📏 Roughly 200K-token context window for extended documents and repos.
• 🆕 Incremental refresh of GLM 5 with stronger coding and reasoning.
• ⚡ Ships as an FP8 checkpoint for efficient serving.
• 💬 Supports reasoning traces, function calling, and web search.
• 🌐 Open weights published on Hugging Face under MIT.

Z.ai

Z.ai, formally Knowledge Atlas Technology Joint Stock Co., Ltd., is a Chinese technology company specializing in artificial intelligence. Previously known internationally as Zhipu AI, the company rebranded to Z.ai in 2025. Its core focus is the GLM family of…

GLM 5.1 is Z.ai's next-generation flagship large language model, positioned for agentic engineering, complex software tasks, and long-horizon planning with extended tool use. It is released under the MIT license, continuing the open-weight strategy the company (formerly Zhipu AI) has applied across its GLM family. The catalog lists a roughly 200K-token context window, and the model ships in an FP8 quantization for efficient deployment.

Z.ai describes GLM 5.1 as an evolution of GLM 5, built to keep revising and improving across long autonomous runs rather than plateauing early. In its release notes, the company states that, relative to GLM 5, version 5.1 delivers gains in coding, agentic tool use, reasoning, and long-horizon agentic tasks. It is further tuned for agentic coding workflows, with adjustments to its chat template for deferred tool loading.

On Z.ai's own reported benchmarks, GLM 5.1 scores 58.4 on SWE-Bench Pro, and the company says it improves over its predecessor GLM 5 across major coding, mathematical reasoning, and agentic evaluations. Capabilities exposed through the catalog include reasoning, function calling, and web search.

In the family timeline, GLM 5.1 follows GLM 5 and earlier releases such as GLM 4.7, and precedes the later GLM 5.2, which Z.ai positions as a further step in long-horizon capability.