Z AI released the proprietary reasoning model GLM-5.3 (max) on August 18, 2026. The model accepts and generates text only, does not process images, and supports a 1 million-token context window, roughly equivalent to 1,500 A4 pages in 12-point Arial. It has 753 billion parameters and is available through one API provider. GLM-5.3 (max) scored 60 on the Artificial Analysis Intelligence Index, compared with a median score of 35 for reasoning models in a similar price tier. The composite index measures capabilities including reasoning, knowledge, mathematics and coding. The model produced 170 million output tokens during the evaluation, substantially above the 72 million-token median for comparable models, and the full evaluation cost $1,238.50. Z AI’s API pricing is $1.40 per million input tokens and $4.40 per million output tokens, versus medians of $1.75 and $10.00, respectively, for comparable models. Artificial Analysis calculates a blended price of $0.90 per million tokens using a 7:2:1 cache-hit, input and output token mix. The model uses extended thinking or chain-of-thought reasoning for complex problems, while its weights are not publicly available.

GLM-5.1 introduces enhancements for long-horizon tasks, improving the model's ability to manage extended interactions and complex reasoning. The update focuses on refining task planning and execution capabilities for AI applications.