Managed Inference and Agents API with Claude Sonnet 4.6

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When to Use This Model
Usage

Last updated February 18, 2026

Claude Sonnet 4.6 is a large language model (LLM) in Anthropic’s Claude family that supports conversational chat, tool calling, and enhanced reasoning for complex tasks with extended thinking. It’s a high-performing model designed to support enterprise applications. This version, claude-sonnet-4-6, offers better performance than the claude-4-5-sonnet model.

Model ID: claude-sonnet
Region: us, eu

When to Use This Model

Claude Sonnet 4.6 is ideal for complex tasks like data processing, sales forecasting, and nuanced content generation. It’s optimized for enterprise apps and offers intelligence, speed, and advanced capabilities for agents, coding, and content generation.

Usage

Claude Sonnet 4.6 follows our Claude /v1/chat/completions API schema.

To provision access to the model, attach a Managed Inference and Agents add-on to your app $APP_NAME:

heroku addons:create heroku-inference:standard -a $APP_NAME

Using config variables, you can invoke the model in various ways:

Heroku CLI ai plugin (heroku ai:models:call)
curl
Python
Ruby
Javascript

Multimodal Support

Supported inputs: text, image
Supported outputs: text

Rate Limits

Maximum requests per minute: 150
Maximum tokens per minute: 800,000

Prompt Caching

Prompt caching is supported for system prompts and tools. The minimum tokens required for prompt caching is 1,024.

Example curl Requests

To retrieve and export your API credentials:

export INFERENCE_KEY=$(heroku config:get -a $APP_NAME INFERENCE_KEY)
export INFERENCE_URL=$(heroku config:get -a $APP_NAME INFERENCE_URL)

Text to Text

curl $INFERENCE_URL/v1/chat/completions \
-H "Authorization: Bearer $INFERENCE_KEY" \
-d @- <<EOF
{
  "model": "claude-sonnet-4-6",
  "messages": [
    { "role": "user", "content": "Hello!" },
    { "role": "assistant", "content": "Hi there! How can I assist you today?" },
    { "role": "user", "content": "What's the weather like in Portland, Oregon right now?" }
  ],
  "temperature": 0.5,
  "max_tokens": 100,
  "stream": false,
  "tools": [
    {
      "type": "function",
      "function": {
        "name": "get_weather",
        "description": "Fetches the current weather for a given city.",
        "parameters": {
          "type": "object",
          "properties": {
            "location": {
              "type": "string",
              "description": "The city and state, e.g. San Francisco, CA"
            }
          },
          "required": ["location"]
        }
      }
    }
  ],
  "tool_choice": "auto"
}
EOF

Image to Text

curl -X POST "$INFERENCE_URL/v1/chat/completions" \
  -H "Authorization: Bearer $INFERENCE_KEY" \
  -H "Content-Type: application/json" \
  -d @- <<EOF
{
  "model": "claude-sonnet-4-6",
  "messages": [
    {
      "role": "user",
      "content": [
        {
          "type": "text",
          "text": "What do you see in this image?"
        },
        {
          "type": "image_url",
          "image_url": {
            "url": "https://upload.wikimedia.org/wikipedia/commons/thumb/e/ec/Heroku_logo.svg/960px-Heroku_logo.svg.png"
          }
        }
      ]
    }
  ]
}
EOF

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