Best AI Assistants Software in 2026

Sonnet 5 propagates across every distribution surface the week it ships, while assistants pry open their model layer.

The defining pattern this week was distribution speed, not raw capability. Anthropic's Sonnet 5 shipped June 30, and within seventy-two hours it was generally available inside GitHub Copilot, live on AWS Bedrock, and typed into the Anthropic TypeScript SDK as a first-class model id. A frontier model no longer lands at one endpoint; it lands across the entire…