GLM 5.3

GLM-5.3 is Z.ai's reasoning model with a 1M-token context window, built for complex software engineering and long-horizon agent tasks.

Strengths

Handles extended reasoning over very long contexts and multi-step agent workflows involving software engineering and system design.

Best for

Tasks requiring deep reasoning across large codebases, complex documentation, or extended problem-solving horizons where context window size is critical.

Limitations

Newer release with limited real-world deployment history; reasoning models typically trade off speed and token efficiency for capability on harder tasks.