> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.mixlayer.com/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.mixlayer.com/_mcp/server.

# GLM 5.3

> Guidance for coding and agentic workloads with GLM 5.3

GLM 5.3 is Z.ai's model for complex coding and long-horizon work. It supports tool-driven workflows with always-on reasoning and native `Low`, `High`, and `Max` effort levels.

## Model details

* **Identifier:** `z-ai/glm-5.3`
* **Context window:** 256K tokens
* **Capabilities:** Text · Reasoning · Tools
* **Reasoning levels:** Low · High · Max

## Best for

* Working across large codebases
* Long-running coding and migration tasks
* Multi-step tool use and automation
* Sustained agent workflows that need adjustable reasoning effort

## Platform defaults

When sampling parameters are omitted, Mixlayer applies:

```json
{
  "temperature": 1.0,
  "top_p": 0.95
}
```

## Reasoning behavior

GLM 5.3 defaults to native `Max` effort. Thinking cannot be disabled.

| Requested effort     | GLM 5.3 behavior |
| -------------------- | ---------------- |
| Omitted or `default` | Native `Max`     |
| `none`               | Rejected         |
| `minimal` or `low`   | Native `Low`     |
| `medium` or `high`   | Native `High`    |
| `xhigh` or `max`     | Native `Max`     |

Set the value through `reasoning_effort` in Chat Completions or `reasoning.effort` in Responses.

Requests with `none` return an `invalid_request_error` with code `unsupported_parameter`.

Budget enough output tokens for both reasoning and the final answer. Different effort values select the model's native behavior, not a fixed reasoning-token budget.

## Working with long context

Provide relevant repository context, identify authoritative files, and state the expected outcome. Break long tasks into verifiable milestones so tool results and intermediate changes can be checked before continuing.

When preparing a new turn, Mixlayer clears reasoning from assistant messages before the latest user message while preserving their visible answers and tool calls. Reasoning from assistant messages after the latest user message is retained, including during tool-call continuations.

> **Info**
>
> Use the Mixlayer console or `GET /v1/models` to confirm the model identifier,
> context limit, and availability for your API key.

See the [official GLM 5.3 model card](https://huggingface.co/zai-org/GLM-5.3) for upstream architecture and capabilities.