# Claude Sonnet 5

> Anthropic's Sonnet-class model for coding, agents and professional work, with adaptive thinking and tool calling.

## Key facts

- Model author: Anthropic
- Input: $2.00 per 1M tokens
- Output: $10.00 per 1M tokens
- Cached input: $0.20 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: 2026-06-30
- Knowledge cutoff: Jan 2026
- Model IDs: `anthropic/claude-sonnet-5`, `jd/claude-sonnet-5`
- Model page: https://www.realrelay.ai/model/anthropic/claude-sonnet-5

## Overview

Claude Sonnet 5 is a Sonnet-class model from Anthropic built for coding, agents and professional work. It supports adaptive thinking, so the model chooses how much to reason for each request. It also supports tool calling and image input, and offers a 1M-token context window for long projects and documents.

Claude Sonnet 5 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 June 30, 2026. Its knowledge cutoff is January 2026.

## Capabilities

Claude Sonnet 5 supports reasoning, tool calling and image understanding. It accepts text and image as input and produces text as output.

Adaptive thinking lets Claude Sonnet 5 adjust how much it reasons from one request to the next. Tool calling makes it usable as the core of a coding or workflow agent, and image input adds screenshots and charts to the context.

## Pricing

Claude Sonnet 5 costs $2.00 per 1M input tokens and $10.00 per 1M output tokens. Cache reads are $0.20 per 1M tokens.

Claude Sonnet 5 is available through RealRelay's OpenAI-compatible API.

## Use cases

Use Claude Sonnet 5 as the model behind a coding agent: it can read a repository in its 1M-token window, call tools to edit files and run tests, and revise its changes based on the output.

For professional work, it can read long documents with attached charts or screenshots and return summaries, structured data or draft responses.

## 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-5", "messages": [{"role": "user", "content": "Hello"}]}'
```

## FAQ

### What is Claude Sonnet 5?

Claude Sonnet 5 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 5 cost?

Claude Sonnet 5 costs $2.00 per 1M input tokens and $10.00 per 1M output tokens, with cache reads at $0.20 per 1M tokens.

### What is the context window of Claude Sonnet 5?

Claude Sonnet 5 has a 1M-token context window and can generate up to 128K tokens in a single response.

### What inputs and outputs does Claude Sonnet 5 support?

Claude Sonnet 5 accepts text and image input and returns text output.

### Does Claude Sonnet 5 support tool calling?

Yes. Claude Sonnet 5 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 5 released?

Claude Sonnet 5 was released on June 30, 2026. Its knowledge cutoff is January 2026.

### How do I call Claude Sonnet 5 via the API?

Call Claude Sonnet 5 through RealRelay's OpenAI-compatible API using the model ID anthropic/claude-sonnet-5.