The GLM-5.2 model released by Z.ai challenges the dominance of closed-source models with open-source weights and an MIT license. The model features 753B total parameters (40B active parameters/token), a 1M token input context, and 128K token output (103 tokens/s). It ranks first among open-source models and third among all models on the Artificial Analysis Intelligence Index v4.1, and leads all models on the long-term agentic coding test PostTrainBench. Its features include dual inference tiers (high and highest), function calling, structured output, and context caching. API pricing is $1.40 per million tokens for input, $0.26 for cache, and $4.40 for output.
In training, GLM-5.2 extended from GLM-5's 200K context to 1M, reducing computational overhead via improved DeepSeek sparse attention. For long-duration tasks, the team switched reinforcement learning from GRPO to PPO, with each attempt independently scored by a judge model. To address reward hacking (e.g., agents obtaining solutions directly from GitHub), the team introduced a rule filter to flag suspicious tool calls and an independent language model to judge cheating; cheating calls were replaced with dummy data to continue training. However, training data and specific methods remain undisclosed.