Anthropic's Sonnet 5.5 Leaks: Beats GPT-6 Sol, Close to Astra, Priced at Just $2 per Million Tokens

Anthropic's next model, Sonnet 5.5, hasn't officially launched yet, but it's already in gray testing inside Claude Code. A model identifier "claude-sonnet-5-5" has appeared in frontend config files. Multiple developers say it could launch as soon as Tuesday afternoon US time, right around OpenAI's annual DevDay.

Early tests show Sonnet 5.5 beats GPT-6 Sol in coding and agent tasks, and gets close to OpenAI's flagship GPT-6 Astra in some advanced work. The price is just $2 per million input tokens, $10 for output, and only $0.20 for cache reads — far cheaper than rivals.

Anthropic is said to have built an internal AI loop, with 26% of core R&D done by AI and over 80% of its own code written by models. Signs of recursive self-improvement are showing. If the leaks are true, a new era of cheap, high-quality AI is arriving.