# Fuyu-8B
Fuyu-8B is an 8-billion-parameter multimodal language model released by [Adept AI](https://www.edgepedia.org/adept-ai) on October 17, 2023, built as a decoder-only transformer that processes image patches directly, without a separate vision encoder.[1](https://www.adept.ai/blog/fuyu-8b/) • [2](https://huggingface.co/docs/transformers/main/en/model_doc/fuyu) Adept positioned it for digital-agent work: answering questions about graphs, diagrams, software user interfaces, and documents. It is a small, openly licensed version of the multimodal model that powers Adept's copilot product.[1](https://www.adept.ai/blog/fuyu-8b/) • [3](https://thesequence.substack.com/p/fuyu-8b-makes-the-case-for-simple)
| Fact | Detail |
|---|---|
| Developer | Adept AI[1](https://www.adept.ai/blog/fuyu-8b/) |
| Release date | October 17, 2023 (added to Hugging Face Transformers October 19, 2023)[2](https://huggingface.co/docs/transformers/main/en/model_doc/fuyu) |
| Parameters | 8 billion[2](https://huggingface.co/docs/transformers/main/en/model_doc/fuyu) |
| Modalities | Text and images[2](https://huggingface.co/docs/transformers/main/en/model_doc/fuyu) |
| Context size | 16K tokens[2](https://huggingface.co/docs/transformers/main/en/model_doc/fuyu) |
| License | CC-BY-NC[1](https://www.adept.ai/blog/fuyu-8b/) |
| Published artifacts | Model weights and example code on Hugging Face; no training data or training code[4](https://huggingface.co/adept/fuyu-8b) |
## Architecture: the encoder-free bet
Fuyu drops the encoder entirely. According to Adept's announcement and model card, Fuyu is a vanilla decoder-only transformer: image patches are linearly projected directly into the first layer of the transformer, bypassing the embedding lookup.[1](https://www.adept.ai/blog/fuyu-8b/) • [4](https://huggingface.co/adept/fuyu-8b) Adept reported responses for large images in under 100 milliseconds.[1](https://www.adept.ai/blog/fuyu-8b/)
Variable-resolution handling follows from the same design. Image tokens are treated like text tokens and read in raster-scan order, with a special image-newline character marking where an image line ends; image positional embeddings are removed entirely. The [Hugging Face Transformers](https://www.edgepedia.org/hugging-face-transformers) documentation notes that this avoids separate training phases for different image resolutions.[1](https://www.adept.ai/blog/fuyu-8b/) • [2](https://huggingface.co/docs/transformers/main/en/model_doc/fuyu)
Adept previewed capabilities of its larger internal model built on this architecture, including OCR on high-resolution images, fine-grained localization in both directions (bounding box from text and text from bounding box, via `bbox_to_text` and `text_to_bbox`), and question answering about UI screenshots.[1](https://www.adept.ai/blog/fuyu-8b/)
What Adept did not publish matters as much as what it did. The release came with no paper and no description of the training dataset; community members asked for exactly these and none appeared with the release.[5](https://news.ycombinator.com/item?id=37931294)
## Benchmarks: vendor claims, no independent verification
Adept's published benchmark table, reproduced on the model card, reports the following scores. Every number below is vendor-reported.
| Eval task | Fuyu-8B | Fuyu-Medium | LLaVA 1.5 (13.5B) | Qwen-VL (10B) | PaLI-X (55B) | PaLM-e-12B | PaLM-e-562B |
|---|---|---|---|---|---|---|---|
| VQAv2 | 74.2 | 77.4 | 80 | 79.5 | 86.1 | 76.2 | 80.0 |
| OKVQA | 60.6 | 63.1 | n/a | 58.6 | 66.1 | 55.5 | 66.1 |
| COCO Captions | 141 | 138 | n/a | n/a | 149 | 135 | 138 |
| AI2D | 64.5 | 73.7 | n/a | 62.3 | 81.2 | n/a | n/a |
Source: Adept's announcement and the [Hugging Face](https://www.edgepedia.org/hugging-face) model card.[1](https://www.adept.ai/blog/fuyu-8b/) • [4](https://huggingface.co/adept/fuyu-8b)
Adept drew two comparisons from this table: Fuyu-8B improves over Qwen-VL and PaLM-e-12B on 2 of 3 metrics despite having 2B and 4B fewer parameters respectively, and Fuyu-Medium performs comparably to PaLM-e-562B with under a tenth of the parameters.[1](https://www.adept.ai/blog/fuyu-8b/)
Adept also criticized the benchmarks themselves, arguing that rigid reference-answer scoring undercounts correct responses. Its example: a model answering "snare" to an image of a drum scores 0 because every reference answer is simply "drum". The company noted as a further sign of benchmark noise that Fuyu-Medium scores slightly worse than Fuyu-8B on COCO CIDEr.[1](https://www.adept.ai/blog/fuyu-8b/) Note that the reader-facing benchmarks MMMU, ChartQA, and DocVQA do not appear in Adept's published table; only VQAv2, OKVQA, COCO Captions, and AI2D are documented.
## Licensing and availability
Fuyu-8B was released under CC-BY-NC, a non-commercial license, with weights and example code on Hugging Face but no training data or training code.[1](https://www.adept.ai/blog/fuyu-8b/) • [4](https://huggingface.co/adept/fuyu-8b) Adept described it as a raw model release: no instruction tuning, postprocessing, or sampling strategies were added to control undesirable outputs, and the company told users to expect to fine-tune the model for their use case.[1](https://www.adept.ai/blog/fuyu-8b/)
The license drew immediate pushback. In the October 2023 Hacker News discussion, commenters disputed the "open source" framing, arguing the CC-BY-NC pre-trained model is at best source-available, and one called the license "a complete non-starter for almost anything". Others pointed to locally runnable alternatives with more permissive terms, naming LLaVA, IDEFICS, CogVLM, and Mini-GPT.[5](https://news.ycombinator.com/item?id=37931294)
## References
1. [Fuyu-8B: A Multimodal Architecture for AI Agents, Adept AI blog](https://www.adept.ai/blog/fuyu-8b/)
2. [Fuyu, Hugging Face Transformers documentation](https://huggingface.co/docs/transformers/main/en/model_doc/fuyu)
3. [Fuyu-8B Makes the Case for Simple, Fast, and Powerful Generative AI Models, The Sequence](https://thesequence.substack.com/p/fuyu-8b-makes-the-case-for-simple)
4. [adept/fuyu-8b, Hugging Face model card](https://huggingface.co/adept/fuyu-8b)
5. [Fuyu-8B: A multimodal architecture for AI agents, Hacker News discussion](https://news.ycombinator.com/item?id=37931294)
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*Topic: Encyclopedia › Technology and the built world › Computing and digital systems › Modern AI: foundation models, generative AI, and the AI industry › Model families and named models › Multimodal, vision, and world models*
*Initially written Sep 17, 2026 · Edited: Oct 11, 2026; Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license