Claude Opus 4.6

Text Generation • Anthropic

anthropic/claude-opus-4.6

• Third-party
• Zero data retention

Claude Opus 4.6 is Anthropic's flagship language model built for complex, multi-step work in coding, financial analysis, and legal reasoning. It uses extended thinking to work through complex problems carefully and features a one million token context window.

Usage

const response = await env.AI.run(
  'anthropic/claude-opus-4.6',
  {
    max_tokens: 1024,
    messages: [{ content: 'What are the three laws of thermodynamics?', role: 'user' }],
  },
)
console.log(response)

curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/v1/messages \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "anthropic/claude-opus-4.6",
  "max_tokens": 1024,
  "messages": [
    {
      "content": "What are the three laws of thermodynamics?",
      "role": "user"
    }
  ]
}'

# The Laws of Thermodynamics

Here are the three main laws (along with the "zeroth" law often included):

## Zeroth Law
If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other. (This establishes the concept of temperature.)

## First Law
Energy cannot be created or destroyed, only transferred or converted from one form to another. In essence, this is the **conservation of energy**. The change in a system's internal energy equals the heat added minus the work done by the system.

## Second Law
The total **entropy** (disorder) of an isolated system can never decrease over time. Heat naturally flows from hotter to cooler objects, not the reverse. This means no process is perfectly efficient, and it establishes the "arrow of time."

## Third Law
As a system's temperature approaches **absolute zero** (0 Kelvin / −273.15°C), its entropy approaches a minimum value. It is impossible to reach absolute zero in a finite number of steps.

---

Together, these laws govern how energy behaves in all physical and chemical processes, from engines to stars to biological systems.

{
  "content": [
    {
      "text": "# The Laws of Thermodynamics\n\nHere are the three main laws (along with the \"zeroth\" law often included):\n\n## Zeroth Law\nIf two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other. (This establishes the concept of temperature.)\n\n## First Law\nEnergy cannot be created or destroyed, only transferred or converted from one form to another. In essence, this is the **conservation of energy**. The change in a system's internal energy equals the heat added minus the work done by the system.\n\n## Second Law\nThe total **entropy** (disorder) of an isolated system can never decrease over time. Heat naturally flows from hotter to cooler objects, not the reverse. This means no process is perfectly efficient, and it establishes the \"arrow of time.\"\n\n## Third Law\nAs a system's temperature approaches **absolute zero** (0 Kelvin / −273.15°C), its entropy approaches a minimum value. It is impossible to reach absolute zero in a finite number of steps.\n\n---\n\nTogether, these laws govern how energy behaves in all physical and chemical processes, from engines to stars to biological systems.",
      "type": "text"
    }
  ],
  "gatewayMetadata": {
    "keySource": "BYOK"
  },
  "id": "msg_01Ss13EYxkyh29CJXYkdhHk4",
  "model": "claude-opus-4-6",
  "role": "assistant",
  "stop_details": null,
  "stop_reason": "end_turn",
  "stop_sequence": null,
  "type": "message",
  "usage": {
    "input_tokens": 17,
    "output_tokens": 257
  }
}

Examples

<details>

<summary>With System Message — Using a system message to set context</summary>

const response = await env.AI.run(
  'anthropic/claude-opus-4.6',
  {
    max_tokens: 1024,
    messages: [{ content: 'How do I read a JSON file in Python?', role: 'user' }],
    system: 'You are a helpful coding assistant specializing in Python.',
    temperature: 0.3,
  },
)
console.log(response)

curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/v1/messages \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "anthropic/claude-opus-4.6",
  "max_tokens": 1024,
  "messages": [
    {
      "content": "How do I read a JSON file in Python?",
      "role": "user"
    }
  ],
  "system": "You are a helpful coding assistant specializing in Python.",
  "temperature": 0.3
}'

````

Reading a JSON File in Python

Python has a built-in json module that makes it easy to read JSON files. Here are the most common approaches:

Basic Example

```python import json