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

# Claude Opus 5.5

> Anthropic's Claude Opus 5.5 language model. See supported inputs, parameters, pricing, response fields, and API examples.

Claude Opus 5.5 is Anthropic's Opus model from the Claude 5.5 family, released September 22, 2026, for agentic coding, long-running agents, and knowledge work. It takes text and image input, outputs text, and carries a 1M token context window with up to 128k output tokens. Adaptive thinking is always on and cannot be disabled; effort defaults to `medium`.

## Model

```
anthropic/claude-opus-5-5
```

|              |                 |
| ------------ | --------------- |
| **Provider** | Anthropic       |
| **Name**     | Claude Opus 5.5 |

## Supported Endpoints

All three API formats are supported:

* [Chat Completions](/api-reference/v1-chat-completions) — `POST /v1/chat/completions`
* [Responses](/api-reference/v1-responses) — `POST /v1/responses`
* [Messages](/api-reference/v1-messages) — `POST /v1/messages`

## Example

```bash theme={null}
curl -X POST https://api.unifically.com/v1/messages \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "anthropic/claude-opus-5-5",
    "max_tokens": 4096,
    "messages": [
      {"role": "user", "content": "Design a distributed job queue with exactly-once semantics."}
    ]
  }'
```

<Note>
  **Volume discounts** are available for almost all models. Reach out at [contact@unifically.com](mailto:contact@unifically.com) to discuss custom pricing.
</Note>