Hermes 4 405B
Nous Research · 2025-08-26 · 405.9B parameters
Hermes 4 405B is Nous Research's hybrid-mode reasoning model, a full-parameter fine-tune of Llama-3.1-405B released in August 2025. It introduces toggleable extended thinking via <think> tags and was trained on roughly 5 million samples and 60 billion post-training tokens spanning verified reasoning traces, math, code, and general instruction data. Because those corpus figures are approximate, no exact training-token count is recorded.