Z.ai debuts GLM-5.3 with long-horizon coding, cybersecurity upgrades
Chinese artificial intelligence developer Z.ai Co. today debuted GLM-5.3, an open-source large language model that set records across several popular benchmarks.
The LLM is based on an algorithm called GLM-5.2 that the company released in mid-July. The latter model features a mixture of experts architecture with 753 billion parameters and a context window of 1 million tokens. GLM-5.3 has an identical design, but went through a more extensive post-training process.
Z.ai says that its training optimizations delivered significant performance improvements. GLM-5.3 achieved the highest score of any open-source AI model on Terminal Bench 3.0, which measures LLMs’ command line scripting capabilities. It performed 50% better than GLM-5.2 on an internal Z.ai benchmark for evaluating coding agents.
Notably, the model is also highly adept at cybersecurity research. It outperformed Claude Mythos 5 on CyberGym, a benchmark that evaluates LLMs’ ability to find code vulnerabilities. GLM-5.3 fell behind Anthropic’s flagship LLM on two other cybersecurity benchmarks.
