HIP-0003: Jin — An Unbuilt Multimodal Model

Abstract

Jin names Hanzo's joint-embedding multimodal model line. It is not built:

• No Jin weights exist.
• hanzoai/jin is archived (ARCHIVED.md at 9f3d7d0e) and holds a copy of LumenPallidium/jepa (MIT): I-JEPA and Saccade-JEPA experiments. No Hanzo commit touches that code.

This HIP records what exists, reserves the name, and states what a Jin release must carry before this HIP moves to Final. Until then it is Draft.

Motivation

Two surfaces describe Jin as if it existed:

• The papers. hanzoai/papers holds hanzo-jin and hanzo-jin-architecture. They report results, including 82.1% zero-shot ImageNet accuracy, with no checkpoint or harness behind them.
• The site. hanzo.ai/jin links to the private repository and to docs.hanzo.ai/docs/jin, which answers 404.

A reader could take these as a model they can use. There is none.

Specification

The key words MUST, MUST NOT, SHOULD, SHOULD NOT and MAY are to be interpreted as in RFC 2119.

§1 What exists

zenlm/vjepa2 is a public fork of facebookresearch/vjepa2. No repository calls it Jin, and this HIP does not.

§2 The name

Jin names a joint-embedding multimodal model line. Until §3 is met, no surface MAY list Jin as a model that can be called or downloaded: not hanzo.ai, not docs.hanzo.ai, not /v1/models (HIP-0039 §2.2), and not a catalog.

§3 Release contract

This HIP moves to Final only when all of the following hold:

1. Weights. Jin weights are public on Hugging Face under zenlm or hanzoai. The card meets HIP-0039 §3 items 1, 2, 4, 5 and 6. Item 3, the Qwen3 base, is a Zen rule and does not bind Jin.
2. Code. Public code loads those weights and reproduces one stated evaluation, with the command, revision, hardware and date. Per HIP-0135, code a release depends on is public.
3. Rewrite. This HIP is rewritten to the modalities, size and objective the released config and code actually have. No figure from the papers carries over without its own receipt.
4. Safe format. The weights are safetensors. A pickled checkpoint runs code when it is loaded.

Rationale

• Why a HIP for an unbuilt model. HIP-0019 requires HIP-0003, and HIP-0511 and hanzo.ai cite Jin. Numbers are never reused, and a missing HIP would leave those references pointing at nothing. A Draft that says "not built" is the accurate target for them.
• Why Draft and not Final. Final means the thing exists in code. It does not.
• Why not re-specify Jin as the JEPA research. That code is a copy of a third party's MIT repository. It is archived and private, and ARCHIVED.md says no successor continues it. Specifying it as Jin would claim someone else's work and describe work nobody is doing.

Security Considerations

• Numbers with no model behind them. No Jin model exists, so there is no model to attack. The risk is the claims: someone who relies on published numbers for a model that does not exist is relying on nothing. §2 is the control, and it is checkable by fetching the surfaces it names.
• Attribution. The copied JEPA code is MIT-licensed, and its LICENSE names the upstream author. Any release built from that code MUST keep the upstream copyright notice, as the MIT licence requires.

References

• HIP-0002 HLLM; HIP-0019 tensor operations, which requires this HIP; HIP-0039 Zen; HIP-0135 what is public; HIP-0511 model families.
• hanzoai/jin ARCHIVED.md at 9f3d7d0e.
• Upstream code: https://github.com/LumenPallidium/jepa (MIT).
• I-JEPA: https://arxiv.org/abs/2301.08243

Copyright

Copyright and related rights waived via CC0.