Mammoth-1

Base Labs' 27B open-weight decision model for classification, routing, and scoring.

Also known as mammoth-1, baseten-mammoth-27b

What it does

Mammoth-1 is a 27 billion parameter decision model from Base Labs at Baseten, released in a technical report dated October 21, 2026. It is a full fine-tune of Qwen3.5-27B. You give it a state, as text and optionally images, and a set of questions, and it returns a probability for each allowed answer instead of generating text. The model card's question types are yes/no, a choice among named options, and a score on ordered levels. Base Labs scores it at 71.24, first of 208 models on the Jev Decision Index 0.4. The model card lists an MIT license and a 16,384-token maximum sequence length, and says the Baseten API is free through October 27, 2026 at 11:59 PM PT, with zero data retention on by default.

Who is Mammoth-1 for?

Developers who want an open-weight model for routing, classification, or rubric scoring.

Tags

• open-weight
• routing
• classification