# GLM 5.1

Autonomous reasoning model with 8+ hour planning capability. Specialized for long-horizon tasks, autonomous planning, and complex engineering.

## Overview

- **Provider:** ZAI
- **Model ID:** `glm-5.1`
- **Type:** Chat
- **Canonical URL:** https://modelstack.cc/models/chat/glm-5.1
- **Version:** 5.1
- **Best for:** Long-horizon tasks, autonomous planning, complex engineering, agentic workflows

## Pricing

| Usage | Price |
| --- | ---: |
| Input | $1.4 / 1M tokens |
| Output | $4.4 / 1M tokens |
| Cache read | $0.26 / 1M tokens |
| Cache write (5 minutes) | $1.4 / 1M tokens |

## Specifications

- **Context window:** 203K
- **Maximum output:** 64K
- **Typical latency:** 18 ms
- **Released:** 2025-12

## Capabilities

- chat
- tool_use
- reasoning
- coding
- analysis

## API usage

Use this model ID in a ModelStack API request:

```json
{
  "model": "glm-5.1"
}
```

For the rendered page, visit https://modelstack.cc/models/chat/glm-5.1.