gpt-oss-120b vs Claude Sonnet 5.5

OpenAI gpt-oss-120bAnthropic Claude Claude Sonnet 5.5
VendorOpenAIAnthropic Claude
Context window131,0721,000,000
Max output131,072128,000
ReasoningNoYes
Tool callingYesYes
File inputNoYes
Inputtexttext, image, file
Outputtexttext
Released—2026-09-28