LLMilestonesA milestone timeline of AI and large language models

Act V · Reasoning and agents

Open modelOpenAI

gpt-oss: OpenAI opens weights again

Two open-weight reasoning models, 120B and 20B, under Apache 2.0.

Nearly 6 yearssince its last open language-model weights (GPT-2, Nov 2019)

Why it matters

OpenAI's first open-weight language models since GPT-2.

Built on

GPT-2

Source: openai.com ↗

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