xAI releases Grok 4 Fast
Grok 4 Fast released — reasoning and non-reasoning modes unified in one set of weights and switched via the system prompt. 2M-token context, 40% fewer thinking tokens
Why it matters
An early case of merging reasoning and non-reasoning models into a single set of weights — a direction that later became the industry standard
Source — Primary sources first; secondary reports are labelled “Press”
Officialx.aihttps://x.ai/news/grok-4-fastAdded in Week 35, 2026 · See that week