Model page
GPT OSS 120B Fast
OpenAI's GPT OSS 120B routed through Cerebras chat completions for very fast tool-capable replies. 131k context. Does not support web search or image input.
Key dates
We use concrete dates and keep them consistent across the site.
Capability
Intelligence
High
Capability
Speed
Fast
Capability
Context window
131,072 tokens
Modalities
Input and output
Input: Text
Output: Text
Features
Availability notes
Function calling supported · Cerebras-hosted fast path on just4o.chat · 1 premium request per send
ChatGPT
GPT‑4o retirement (ChatGPT)
OpenAI is retiring GPT‑4o inside ChatGPT on February 13, 2026. This does not automatically imply API removal.