You give it a question, a screenshot, or a full coding task, and it answers, explains what it sees, or writes the code. It is the first model in the new GLM-5 family built to be multimodal from the ground up: the same model that fixes your Python script can also read the error dialog you screenshotted.
The practical difference is speed and cost. Z.ai built it as a mixture-of-experts model: it stores 320 billion parameters of knowledge but activates only 18 billion of them for any given word, so it responds like a much smaller model. The company reports it comes close to Claude Opus 4.8 on coding and agent-style performance tests, and beats its own predecessor at a tenth of the price.
The weights are on Hugging Face under the MIT license, which means you can use them in a commercial product without restrictions.