Grok 4.5 vs GPT-5.4 Mini

xAI Grok 4.5OpenAI GPT-5.4 Mini
VendorxAIOpenAI
Context window500,000400,000
Max output2,000,000128,000
ReasoningYesYes
Tool callingYesYes
File inputYesYes
Inputtext, imagetext, image
Outputtexttext
Released2026-07-072026-03-16