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

# Claude Haiku 4.5 Thinking

> Anthropic's Claude Haiku 4.5 with Extended Thinking — fast reasoning at low cost, great for math, coding, and analysis.

Claude Haiku 4.5 Thinking is the Extended Thinking version of Claude Haiku 4.5, available through Starrise AI via OpenAI-compatible interface. Combining Haiku's speed and cost advantages with step-by-step internal reasoning enabled by default, it significantly improves accuracy on complex tasks while remaining far faster and more affordable than large thinking models.

## Key Capabilities

* **OpenAI-compatible** — Drop-in replacement for the OpenAI SDK, no other code changes needed
* **Extended Thinking** — Step-by-step internal reasoning enabled by default
* **Fast and affordable** — Thinking capability at Haiku-level speed and cost
* **Streaming** — Real-time token streaming via SSE
* **Strong reasoning** — Higher accuracy on math, logic, and multi-step problems

## Quick Example

<CodeGroup>
  ```bash cURL theme={null}
  curl https://ai.alad.com/v1/messages \
    -H "Authorization: Bearer YOUR_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "model": "claude-haiku-4-5-20251001-thinking",
      "messages": [
        { "role": "user", "content": "Solve step by step: A train travels 120 km in 2 hours, then slows down and travels 80 km in 3 hours. What is the average speed for the entire journey?" }
      ]
    }'
  ```

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

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

  response = client.chat.completions.create(
      model="claude-haiku-4-5-20251001-thinking",
      messages=[
          {"role": "user", "content": "Solve step by step: A train travels 120 km in 2 hours, then slows down and travels 80 km in 3 hours. What is the average speed for the entire journey?"}
      ]
  )

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

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

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

  stream = client.chat.completions.create(
      model="claude-haiku-4-5-20251001-thinking",
      messages=[
          {"role": "user", "content": "Prove that there are infinitely many prime numbers."}
      ],
      stream=True
  )

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

## Parameters

| Parameter     | Type           | Required | Description                                       |
| ------------- | -------------- | -------- | ------------------------------------------------- |
| `model`       | string         | Yes      | Fixed value: `claude-haiku-4-5-20251001-thinking` |
| `messages`    | array          | Yes      | Array of `{ role, content }` objects              |
| `max_tokens`  | integer        | No       | Maximum number of tokens to generate              |
| `temperature` | float          | No       | `0`–`2`, 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 where generation stops                  |

<Card title="API Reference" icon="code" href="/en/api-reference/model-api/anthropic/claude-haiku-4-5-20251001-thinking">
  View the interactive API Playground for Claude Haiku 4.5 Thinking.
</Card>