Artificial intelligence · 2025

Claude Sonnet 4.5

An agentic coding model that sustains focus on tasks for over 30 hours.

Released September 29, 2025, Claude Sonnet 4.5 led SWE-bench Verified at 77.2% and OSWorld computer use at 61.4%, up from 42% four months earlier. Anthropic released the Claude Agent SDK alongside it.

See it in the living tree Wikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 1

Claude 4 2025

What it led to 1

Claude Opus 4.5 2025

Related measurements

The dashed line marks when it first worked.

Best AI score on GPQA Diamond Latest: 95.8 % correct (2026) Source: Epoch AI, Capabilities & benchmarking (benchmark_data.zip, gpqa_diamond.csv); Anthropic: Claude 3 public launch (March 4, 2024)

Training compute of notable AI models Source: Epoch AI, Notable AI Models (CC BY 4.0)