# Claude Opus 4.5 (20251101)

> A dated Anthropic Opus snapshot with reasoning, tool calling and image input, classed by Anthropic as a legacy model.

## Key facts

- Model author: Anthropic
- Input: $5.00 per 1M tokens
- Output: $25.00 per 1M tokens
- Cached input: $0.50 per 1M tokens
- Context window: 200,000 tokens
- Maximum output: 64,000 tokens
- Input modalities: image, text
- Output modalities: text
- Capabilities: reasoning, tools, vision
- Released: 2025-11-24
- Knowledge cutoff: May 2025
- Model IDs: `anthropic/claude-opus-4-5-20251101`
- Model page: https://www.realrelay.ai/model/anthropic/claude-opus-4-5-20251101

## Overview

Claude Opus 4.5 (20251101) is a model from Anthropic, identified by the snapshot date 20251101 in its model ID. It supports extended thinking, tool calling and image input. Anthropic classes it as a legacy model that remains available, so teams with integrations already built on this snapshot can keep using it.

Claude Opus 4.5 (20251101) has a 200K-token context window and can generate up to 64K output tokens. It accepts text and image input and returns text output. It was released on November 24, 2025. Its knowledge cutoff is May 2025.

## Capabilities

Claude Opus 4.5 (20251101) supports reasoning, tool calling and image understanding. It accepts text and image as input and produces text as output.

Extended thinking, tool calling and image input work together inside a 200K-token context window, so the model can work through multi-step problems that mix text and screenshots.

## Pricing

Claude Opus 4.5 (20251101) costs $5.00 per 1M input tokens and $25.00 per 1M output tokens. Cache reads are $0.50 per 1M tokens.

Claude Opus 4.5 (20251101) is available through RealRelay's OpenAI-compatible API.

## Use cases

Use Claude Opus 4.5 (20251101) to keep existing applications running on a fixed snapshot, for example a document-review workflow that sends long text and page images and receives a written analysis.

It also supports tool-calling agents that reason in several steps, fetching data through functions and then reasoning over the results within the 200K-token context.

## 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-opus-4-5-20251101", "messages": [{"role": "user", "content": "Hello"}]}'
```

## FAQ

### What is Claude Opus 4.5 (20251101)?

Claude Opus 4.5 (20251101) is a model from Anthropic, identified by the snapshot date 20251101 in its model ID. It supports reasoning, tool calling and image understanding and accepts text and image input.

### How much does Claude Opus 4.5 (20251101) cost?

Claude Opus 4.5 (20251101) costs $5.00 per 1M input tokens and $25.00 per 1M output tokens, with cache reads at $0.50 per 1M tokens.

### What is the context window of Claude Opus 4.5 (20251101)?

Claude Opus 4.5 (20251101) has a 200K-token context window and can generate up to 64K tokens in a single response.

### What inputs and outputs does Claude Opus 4.5 (20251101) support?

Claude Opus 4.5 (20251101) accepts text and image input and returns text output.

### Does Claude Opus 4.5 (20251101) support tool calling?

Yes. Claude Opus 4.5 (20251101) 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 Opus 4.5 (20251101) released?

Claude Opus 4.5 (20251101) was released on November 24, 2025. Its knowledge cutoff is May 2025.

### How do I call Claude Opus 4.5 (20251101) via the API?

Call Claude Opus 4.5 (20251101) through RealRelay's OpenAI-compatible API using the model ID anthropic/claude-opus-4-5-20251101.