AI Potluck
Model components / Fine-tuned / chat models

Jamba 1.5 Large

AI21 Labs

AI21-Jamba-1.5-Large (ai21labs/AI21-Jamba-1.5-Large on HF), hybrid SSM-Transformer (Mamba+Attention) MoE, 398B total / 94B active, 256K context, instruction-tuned chat model with tool use / grounded-RAG / JSON mode. Announced 22 Aug 2024 under the Jamba Open Model License. Stale: superseded by Jamba 1.6 (Mar 2025) and the Jamba2/Jamba Reasoning 3B generation now headlined on ai21.com/jamba. Recategorized from base_pretrained -> finetuned_chat: this is the instruct/chat SKU (post-trained for downstream chat/agentic use), not a raw base model.

Recategorized from base_pretrained -> finetuned_chat; this is the instruct/chat SKU, not a raw base model. The repo is gated `auto`, so openness was read from the model card and the license body rather than a download. Verified 2026-08-13 via the HF model card, the Jamba Open Model License body and the AI21 release blog.

Openness

3 high confidence
3.0
weights
open(downloadable on HF, contact-info gate)
data
closed
code
partial(inference/usage only, no training pipeline)
license
Jamba-Open-Model-License(non-OSI: $50M annual-revenue commercial cap + AUP + naming/attribution requirements)

Weights are downloadable under the Jamba Open Model License, which is not OSI-approved and carries a $50M annual-revenue cap that bars large-entity commercial use; the "Open Model" branding overstates it. A license that bounds commercial use rather than forbidding it caps at 3 rather than 2: the test at that boundary is whether commercial use is permitted at all, and this one permits it for everyone inside the bound, where a license that forbids commerce outright - CC-BY-NC, Mistral's Non-Production License - stays at 2. Nine other products carry a bounded license and all score 3.

  • https://huggingface.co/ai21labs/AI21-Jamba-1.5-Large recorded 2026-08-13

    "The models are released under the Jamba Open Model License, a permissive license allowing full research use and commercial use under the license terms"; `license:other` in the repo tags with `"gated":"auto"`; downloadable safetensors; inference and usage instructions only, no training corpus or pipeline

  • https://www.ai21.com/licenses/jamba-open-model-license recorded 2026-08-13

    license text - "if at any time You and/or Your affiliate(s), whether individually or in aggregate, generate more than fifty million US Dollars (USD $50,000,000) in annual revenue ... then You" must license separately; non-OSI

Adoption

1 high confidence
1.0

The scored release, ai21labs/AI21-Jamba-1.5-Large, reads 45 Hugging Face downloads in the trailing 30 days, which bands at level 1 (<10K). That repository is declared on this product, and adoption is summed across the releases a tier covers.

Capability

3 medium confidence
3.0

A 2024 hybrid SSM-Transformer that led open models on long context at release and is now mid-tier against the 2026 frontier. The HF card's benchmark table gives Jamba 1.5 Large Arena Hard 65.4, MMLU (CoT) 81.2 and MMLU Pro (CoT) 53.5, and AI21's launch post frames the 65.4 as outpacing both Llama 3.1 70B and 405B - a strong placement for its generation, and well short of the 2026 reasoning and coding frontier this category scores against.

Verified 2026-08-12