---
type: "Evidence Item"
title: "Introducing Claude Sonnet 4.5"
description: "Claude Sonnet 4.5 is the best coding model in the world. It's the strongest model for building complex agents. It’s the best model at using computers. And it shows substantial."
resource: "https://www.anthropic.com/news/claude-sonnet-4-5"
tags: ["appendix-iii", "benchmark", "anthropic"]
timestamp: "2025-09-29"
category: "benchmark"
publisher: "Anthropic"
cope_score: 96
confidence: 0.88
---

# Introducing Claude Sonnet 4.5

# Claim

Claude Sonnet 4.5 is the best coding model in the world. It's the strongest model for building complex agents. It’s the best model at using computers. And it shows substantial gains in reasoning and math. Code is everywhere. It runs every application, spreadsheet, and software tool you use. Being able to use those tools and reason through hard problems is.

# Relevance

Appendix III, section one: model and benchmark capability evidence

# Oracle Verdict

Anthropic is describing a frontier or production capability that pushes directly on the thesis. The important signal is not the marketing language; it is the widening set of tasks now being routed through model-driven execution rather than ordinary software or headcount.

# Metadata

* Publisher: Anthropic
* Category: benchmark
* Sector: Software engineering
* Capability: Frontier model release and benchmark movement
* Cope score: 96
* Confidence: 0.88

# Related Concepts

* [Live evidence index](index.md)
* [Thesis](../thesis.md)

# Citations

[1] [Introducing Claude Sonnet 4.5](https://www.anthropic.com/news/claude-sonnet-4-5)