Model reference · open weights

Tooka-SBERT-Large

Available as managed deployment Embeddings PartAI Embeddings 1 variants 1k dl/mo

Tooka-SBERT-Large is an open-weight embedding model from PartAI. AxForge deploys and operates it for you on dedicated EU-owned hardware — with the licence handled where one is required.

Available as managed deployment — configured and operated for you on dedicated EU hardware, quoted per deployment.

What it is

Released byPartAI
TypeEmbedding models
TaskEmbeddings
Parameters (lead)353M
Context512 tokens
Runs withsentence-transformers
Based onPartAI/TookaBERT-Large
Released2025-05-13
Popularity1k downloads / month
LicenceUnknown

About

What Tooka-SBERT-Large is

This model is a Sentence Transformers model trained for semantic textual similarity and embedding tasks. It maps sentences and paragraphs to a dense vector space, where semantically similar texts are close together.

The model is trained in two sizes: Small and Large

Read the full model card

Usage

Direct Usage (Sentence Transformers)

First install the Sentence Transformers library:

pip install sentence-transformers==3.4.1

Then you can load this model and run inference.

from sentence_transformers import SentenceTransformer

# Download from the 🤗 Hub
model = SentenceTransformer("PartAI/Tooka-SBERT-V2-Large")
# Run inference
sentences = [
    'درنا از پرندگان مهاجر با پاهای بلند و گردن دراز است.',
    'درناها با قامتی بلند و بال‌های پهن، از زیباترین پرندگان مهاجر به شمار می‌روند.',
    'درناها پرندگانی کوچک با پاهای کوتاه هستند که مهاجرت نمی‌کنند.'
]
embeddings = model.encode(sentences)
print(embeddings.shape)
# [3, 1024]

# Get the similarity scores for the embeddings
similarities = model.similarity(embeddings, embeddings)
print(similarities.shape)
# [3, 3]

🛠️ Training Details

The training is performed in two stages:

  1. Pretraining on the Targoman News dataset
  2. Fine-tuning on multiple synthetic datasets

Stage 1: Pretraining

  • We use an asymmetric setup.
  • Input formatting:
    • Titles are prepended with "سوال: "
    • Texts are prepended with "متن: "
  • Loss function: CachedMultipleNegativesRankingLoss

Stage 2: Fine-tuning

  • Loss functions:
    • CachedMultipleNegativesRankingLoss
    • CoSENTLoss
  • Used across multiple synthetic datasets

📊 Evaluation

We evaluate our model on the PTEB Benchmark. Our model outperforms mE5-Base on average across PTEB tasks.

For Retrieval and Reranking tasks, we follow the same asymmetric structure, prepending:

  • "سوال: " to queries
  • "متن: " to documents
Model#ParamsPair-Classification-AvgClassification-AvgRetrieval-AvgReranking-AvgCrossTasks-Avg
Tooka-SBERT-V2-Large353M80.2474.7359.8073.4472.05
Tooka-SBERT-V2-Small123M75.6972.1661.2473.4070.62
jina-embeddings-v3572M71.8879.2765.1864.6270.24
multilingual-e5-base278M70.7669.7163.9076.0170.09
Tooka-SBERT-V1-Large353M81.5271.5445.6160.4464.78

Task-Specific Datasets in PTEB

  • Pair-Classification:

    • FarsTail
  • Classification:

    • MassiveIntentClassification
    • MassiveScenarioClassification
    • MultilingualSentimentClassification
    • PersianFoodSentimentClassification
  • Retrieval:

    • MIRACLRetrieval
    • NeuCLIR2023Retrieval
    • WikipediaRetrievalMultilingual
  • Reranking:

    • MIRACLReranking
    • WikipediaRerankingMultilingual

Citation

BibTeX

Sentence Transformers
@inproceedings{reimers-2019-sentence-bert,
    title = "Sentence-BERT: Sentence Embeddings using Siamese BERT-Networks",
    author = "Reimers, Nils and Gurevych, Iryna",
    booktitle = "Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing",
    month = "11",
    year = "2019",
    publisher = "Association for Computational Linguistics",
    url = "https://arxiv.org/abs/1908.10084",
}
CachedMultipleNegativesRankingLoss
@misc{gao2021scaling,
    title={Scaling Deep Contrastive Learning Batch Size under Memory Limited Setup},
    author={Luyu Gao and Yunyi Zhang and Jiawei Han and Jamie Callan},
    year={2021},
    eprint={2101.06983},
    archivePrefix={arXiv},
    primaryClass={cs.LG}
}

From the published model card. Full card on the HuggingFace links in the sidebar.

Using it via the API

Call it like any OpenAI endpoint

Once AxForge deploys tooka-sbert-large for you, it answers on the OpenAI-compatible API — the same base URL and keys as every other model. (tooka-sbert-large below is illustrative; you get the exact model name on deployment.)

$ curl -sS https://api.axforge.ai/v1/embeddings \
  -H "Authorization: Bearer $AXFORGE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"tooka-sbert-large","input":"text to embed"}'

Create an account — your API key is available in the console. 3M free tokens every 30 days with every new account.

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