---
title: Claude Sonnet 4.5
description: Claude Sonnet 4.5 by Anthropic — previous Sonnet generation, still fully supported.
---

# Claude Sonnet 4.5

**Key:** `claude-sonnet-4-5`  
**Provider:** [Anthropic](/en/providers/anthropic/)  
**Support:** `runnable`

## Capabilities

chat · reasoning · tools

## Specifications

| Field | Value |
|-------|-------|
| Context window | 200 000 tokens |
| Input modalities | text |
| Output modalities | text |

## When to use

Previous Sonnet generation. Fully supported and suitable for existing lenses pinned to this version. For new lenses, prefer `claude-sonnet-4-6`.

## Provider documentation

→ [Anthropic migration guide](https://docs.anthropic.com/en/docs/about-claude/models/migrating-to-claude-4)
