> ## Documentation Index
> Fetch the complete documentation index at: https://docs.anyfast.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# GPT-5 Codex Low

> OpenAI's GPT-5 Codex Low — efficient code generation with GPT-5.

GPT-5 Codex Low is available through Anyfast via an OpenAI-compatible interface.

## Key capabilities

* **OpenAI-compatible** — Works as a drop-in replacement with the OpenAI SDK
* **Streaming** — Supports real-time token streaming via SSE
* **Tool use** — Supports function calling and tool use
* **Flexible output** — Supports JSON mode and structured output

## Quick example

<CodeGroup>
  ```bash cURL theme={null}
  curl https://www.anyfast.ai/v1/chat/completions \
    -H "Authorization: Bearer YOUR_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "model": "gpt-5-codex-low",
      "messages": [
        { "role": "user", "content": "Explain quantum entanglement in simple terms." }
      ]
    }'
  ```

  ```python Python theme={null}
  from openai import OpenAI

  client = OpenAI(
      api_key="YOUR_API_KEY",
      base_url="https://www.anyfast.ai/v1"
  )

  response = client.chat.completions.create(
      model="gpt-5-codex-low",
      messages=[
          {"role": "user", "content": "Explain quantum entanglement in simple terms."}
      ]
  )

  print(response.choices[0].message.content)
  ```

  ```python Streaming theme={null}
  from openai import OpenAI

  client = OpenAI(
      api_key="YOUR_API_KEY",
      base_url="https://www.anyfast.ai/v1"
  )

  stream = client.chat.completions.create(
      model="gpt-5-codex-low",
      messages=[
          {"role": "user", "content": "Write a short poem about the sea."}
      ],
      stream=True
  )

  for chunk in stream:
      print(chunk.choices[0].delta.content or "", end="")
  ```
</CodeGroup>

## Parameters

| Parameter         | Type           | Required | Description                                   |
| ----------------- | -------------- | -------- | --------------------------------------------- |
| `model`           | string         | Yes      | Must be `gpt-5-codex-low`                     |
| `messages`        | array          | Yes      | List of `{ role, content }` objects           |
| `max_tokens`      | integer        | No       | Maximum tokens to generate                    |
| `temperature`     | float          | No       | `0`\u20132. Controls randomness. Default: `1` |
| `stream`          | boolean        | No       | Enable SSE streaming. Default: `false`        |
| `top_p`           | float          | No       | Nucleus sampling threshold. Default: `1`      |
| `stop`            | string / array | No       | Sequences that stop generation                |
| `tools`           | array          | No       | List of tools the model may call              |
| `response_format` | object         | No       | Specify output format (e.g. JSON mode)        |

<Card title="API Reference" icon="code" href="/api-reference/model-api/openai/gpt-5-codex-low">
  View the interactive API playground for GPT-5 Codex Low.
</Card>

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