Anthropic Introduces Claude Sonnet 4.5 — Strongest Coding & Safest Model Yet
Anthropic Introduces Claude Sonnet 4.5 Anthropic has announced Claude Sonnet 4.5, which the company calls its strongest coding model to date and its "safest" system yet. Key claims in the release and press coverage: Benchmark performance: Sonnet 4.5 scored a record 61.4% on OSWorld, reportedly 17 percentage points higher than Opus 4.1. Long-running autonomy: The model can autonomously work on multi-step projects for 30+ hours — a major jump from roughly seven hours for Opus 4 at launch. Safety: Anthropic says Sonnet 4.5 underwent extensive safety training and is released under its AI Safety Level 3 framework, with stronger protections against prompt injection and reduced tendencies for sycophancy, deception, power-seeking, and delusional outputs. Product updates: Claude Code received UI improvements and a new "checkpoints" feature for save/rollback during coding sessions.…
