The Stack
The Stack — September 29, 2026
12:46
Daily IT Briefing
AI & Machine Learning
Anthropic ships Sonnet 5.5, its mid-tier workhorse. The second model in the 5.5 family lands as a faster, cheaper complement to Opus 5.5: vendor-reported gains include 30%+ faster output, up to 30% lower cost per task at the same list price ($2/$10 per million input/output tokens), and a striking jump on Terminal-Bench 4.0 (70.6% vs. Sonnet 5's 10.3%).…