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

# Reasoning

> Production-verified reasoning and thinking with the latest GPT, Claude, and Gemini models

> Дата обновления: 2026-06-06

# Reasoning

This page only documents reasoning flows that were **verified with real requests against Crazyrouter production**.

Verification date:

* `2026-03-22`

Verified models:

* `gpt-5.5`
* `claude-opus-4-8`
* `gemini-3.1-pro`

## Verified matrix

| Model             | Protocol           | Endpoint                                      | Success marker                                |
| ----------------- | ------------------ | --------------------------------------------- | --------------------------------------------- |
| `gpt-5.5`         | OpenAI Responses   | `POST /v1/responses`                          | `output` includes a `reasoning` item          |
| `claude-opus-4-8` | Anthropic Messages | `POST /v1/messages`                           | Returns `thinking` block                      |
| `gemini-3.1-pro`  | Gemini Native      | `POST /v1beta/models/{model}:generateContent` | `usageMetadata` includes `thoughtsTokenCount` |

## GPT-5.4

```bash theme={null}
curl https://api.crazyrouter.com/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gpt-5.5",
    "input": "Which is larger, 9.11 or 9.9? Explain briefly.",
    "reasoning": {
      "effort": "high",
      "summary": "detailed"
    }
  }'
```

Verified output types:

```json theme={null}
["reasoning", "message"]
```

Verified `reasoning` item shape:

```json theme={null}
{
  "type": "reasoning",
  "summary": [
    {
      "type": "summary_text",
      "text": "..."
    }
  ]
}
```

## Claude Opus 4.7 Thinking

```bash theme={null}
curl https://api.crazyrouter.com/v1/messages \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-opus-4-8",
    "max_tokens": 320,
    "thinking": {
      "type": "enabled",
      "budget_tokens": 128
    },
    "messages": [
      {
        "role": "user",
        "content": "Which is larger, 9.11 or 9.9? Explain briefly."
      }
    ]
  }'
```

Verified response shape:

```json theme={null}
{
  "content": [
    {
      "type": "thinking"
    },
    {
      "type": "text"
    }
  ]
}
```

## Gemini 3 Pro

```bash theme={null}
curl "https://api.crazyrouter.com/v1beta/models/gemini-3.1-pro:generateContent?key=YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [
      {
        "role": "user",
        "parts": [
          {
            "text": "Which is larger, 9.11 or 9.9? Explain briefly."
          }
        ]
      }
    ],
    "generationConfig": {
      "thinkingConfig": {
        "thinkingBudget": 256
      },
      "maxOutputTokens": 512
    }
  }'
```

Verified production field:

* `usageMetadata.thoughtsTokenCount`

## Current exclusions

* In the current recheck, `gpt-5.5` via Chat Completions did not reliably surface `reasoning_content`, so this page uses the Responses API as the primary GPT example
* Base `claude-opus-4-8` did not return a thinking block in this verification round

## See Also

* [OpenAI Reasoning](/ru/chat/openai/reasoning)
* [GPT-5 Thinking](/ru/chat/responses/gpt5-thinking)
* [Thinking Fields](/ru/reference/thinking)
* [Claude Native Messages](/ru/chat/anthropic/messages)
* [Gemini Native API](/ru/chat/gemini/native)