Model family

Rnj

Family overview — summarizes releases; licenses and availability belong to each release.

Rnj is Essential AI's line of 8B-parameter dense language models trained from scratch and aimed at code and STEM work. Rnj-1 (a base model and an instruction-tuned model) was released in December 2025, followed in 2026 by Rnj-1.5 Instruct, which extends the context window from 32K to 160K tokens.1 3 2

Model hub: Rnj-1 collection (Hugging Face) (external site: huggingface.co)
Release notes: Rnj-1 announcement (external site: essential.ai)
Model hub: Rnj-1 base model card (external site: huggingface.co)

Last reviewedSep 29, 2026Entry updated Sep 29, 2026Documented release Dec 2025

Releases assessed

Each release is assessed on its own. This family has no family-wide openness label.

Releases in the Rnj family
Release	Weights	Tier (USASI rubric v0.1)	License	Released
Rnj-1 Instruct	Weights: Public	Model-disclosure tier (USASI rubric v0.1): Open-weight	Apache-2.0	Dec 2025
Rnj-1.5 Instruct	Weights: Public	Model-disclosure tier (USASI rubric v0.1): Open-weight	Apache-2.0	2026

What it is useful for

The model cards describe the models for code generation, agentic software-engineering tasks, tool calling, math, and science questions. Essential AI says it kept Rnj-1 post-training limited so that others can specialize the models further.1 2

Organization context

Essential AI

Provenance and derivatives

Trained from scratch by Essential AI. The model card says the architecture is similar to Gemma 3 but uses only global attention, with YaRN for long-context extension; Rnj-1.5 instead interleaves block-local and global attention layers. The cards do not name the pretraining datasets.1 2

U.S. eligibility

Project eligibility rests on documented governing or maintaining entities, not on contributors.

Eligible · basis: U.S. headquarters

The models are trained and published by Essential AI, which gives its location as San Francisco, CA. Eligibility of each release is assessed on the release record.1 4

Assessed Sep 29, 2026

Sources

1.
EssentialAI/rnj-1 model card (external site: huggingface.co)
Essential AI · Model card · accessed Sep 29, 2026
2.
EssentialAI/rnj-1.5-instruct model card (external site: huggingface.co)
Essential AI · Model card · accessed Sep 29, 2026
3.
Rnj-1: Our First Instrument of Intelligence (external site: essential.ai)
Essential AI · Announcement · published Dec 5, 2025 · accessed Sep 29, 2026
4.
About | Essential AI (external site: essential.ai)
Essential AI · Official page · accessed Sep 29, 2026

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