# Claude Sonnet 4.6

> Anthropic's Sonnet-class model for coding, agents and professional work, from iterative development to project management.

## Key facts

- Model author: Anthropic
- Input: $2.9042 per 1M tokens (starting price)
- Output: $14.521 per 1M tokens (starting price)
- Cached input: $0.2904 per 1M tokens
- Context window: 1,000,000 tokens
- Maximum output: 128,000 tokens
- Input modalities: image, text
- Output modalities: text
- Capabilities: reasoning, tools, vision
- Released: 2026-02-17
- Knowledge cutoff: Aug 2025
- Model IDs: `anthropic/claude-sonnet-4-6`, `jd/claude-sonnet-4-6`
- Model page: https://www.realrelay.ai/model/anthropic/claude-sonnet-4-6

## Overview

Claude Sonnet 4.6 is a Sonnet-class model from Anthropic built for coding, agents and professional work. Anthropic highlights iterative development, complex codebase navigation and end-to-end project management. It supports reasoning, tool calling and image input, and its 1M-token context window fits large repositories.

Claude Sonnet 4.6 has a 1M-token context window and can generate up to 128K output tokens. It accepts text and image input and returns text output. It was released on February 17, 2026. Its knowledge cutoff is August 2025.

## Capabilities

Claude Sonnet 4.6 supports reasoning, tool calling and image understanding. It accepts text and image as input and produces text as output.

Codebase navigation relies on a long context and tool calling: Claude Sonnet 4.6 can read many files, call tools to search and edit them, and reason about how a change fits. Image input extends this to screenshots and design mockups.

## Pricing

Claude Sonnet 4.6 starts from $2.90 per 1M input tokens and from $14.52 per 1M output tokens. Cache reads start from $0.29 per 1M tokens.

Pricing is tiered, and the price shown is the starting tier. Claude Sonnet 4.6 is available through RealRelay's OpenAI-compatible API.

## Use cases

Use Claude Sonnet 4.6 for iterative development: it can work through a repository, propose edits, call tools to run tests and refine the change over several rounds.

For professional work and project management, it can read long briefs and screenshots, track tasks across a large context and produce plans or status summaries.

## Call it

OpenAI-compatible chat completions:

```bash
curl https://www.realrelay.ai/v1/chat/completions \
  -H "Authorization: Bearer $REALRELAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "anthropic/claude-sonnet-4-6", "messages": [{"role": "user", "content": "Hello"}]}'
```

## FAQ

### What is Claude Sonnet 4.6?

Claude Sonnet 4.6 is a Sonnet-class model from Anthropic built for coding, agents and professional work. It supports reasoning, tool calling and image understanding and accepts text and image input.

### How much does Claude Sonnet 4.6 cost?

Claude Sonnet 4.6 starts from $2.90 per 1M input tokens and from $14.52 per 1M output tokens, with cache reads from $0.29 per 1M tokens. Pricing is tiered, and these are the starting-tier prices.

### What is the context window of Claude Sonnet 4.6?

Claude Sonnet 4.6 has a 1M-token context window and can generate up to 128K tokens in a single response.

### What inputs and outputs does Claude Sonnet 4.6 support?

Claude Sonnet 4.6 accepts text and image input and returns text output.

### Does Claude Sonnet 4.6 support tool calling?

Yes. Claude Sonnet 4.6 supports tool calling, so it can call functions you define and use the results in multi-step tasks. It also supports reasoning and image understanding.

### When was Claude Sonnet 4.6 released?

Claude Sonnet 4.6 was released on February 17, 2026. Its knowledge cutoff is August 2025.

### How do I call Claude Sonnet 4.6 via the API?

Call Claude Sonnet 4.6 through RealRelay's OpenAI-compatible API using the model ID anthropic/claude-sonnet-4-6.