GLM-5.1

Overview

GLM-5.1 is Zhipu AI (Z.ai)‘s previous-generation flagship foundation model, built for agentic engineering, delivering reliable productivity on complex systems engineering and long-horizon agent tasks. Its coding and agent capabilities reach SOTA among open-source models. It accepts text input with a 128K-token context window.

Key Features

Agentic Engineering: Built for complex systems engineering
Open-Source SOTA Coding: Leading coding and agent capability among open source
Still in Supply: The previous-generation flagship still served on the platform

Best Use Cases

Complex Systems Engineering: Long-running engineering and autonomous tasks
Long-Horizon Agents: Multi-step tool use
Chinese Scenarios: Chinese understanding and generation

Specifications

Item	Detail
Platform model ID	`glm-5.1`
Context window	128,000 tokens
Input modalities	Text
Reasoning / thinking	Supported
First released (market)	2026-04
Live pricing	See the model marketplace

Capabilities and Limitations

Capability	Description
Reasoning	Strong. Open-source SOTA coding and agents
Multimodal	Text only (no image/audio/video)
Context Window	128,000 tokens
Speed	Moderate