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alfotech/silas-embedding-0.6b
silas-embedding-0.6b is a feature extraction model from alfotech. Use it when you need embeddings to search or compare text. It is set up for sentence-transformers. The card lists the license as apache-2.0.
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From the Hugging Face model README
Silas Embedding 0.6B is a production-oriented multilingual embedding model developed by Alfo Tech Industries.
Silas converts text into dense vector representations designed for semantic understanding, similarity measurement, knowledge systems, AI search, Retrieval-Augmented Generation, and vector databases. The model is based on Qwen3-Embedding-0.6B and follows an evaluation-first engineering workflow focused on difficult semantic matching scenarios rather than only easy, well-separated cases.
| Property | Specification |
|---|---|
| Model | Silas Embedding 0.6B |
| Organization | Alfo Tech Industries |
| Base Model | Qwen3-Embedding-0.6B |
| Parameters | 0.6B |
| Context Window | 32K |
| Default Embedding Size | 1024 dimensions |
| Supported Dimensions | 32–1024 |
| Languages | 100+ |
| Architecture Type | Text Embedding |
| Instruction Aware | Yes |
| Framework | Sentence Transformers |
| License | Apache-2.0 |
A useful embedding model should do more than place related sentences close together — it should help a downstream system distinguish the correct semantic match from close, plausible-looking alternatives.
Correct Semantic Meaning
│
▼
Silas Embedding
│
▼
Dense Vector Representation
│
┌──────┼────────┐
▼ ▼ ▼
Search RAG Similarity
For this reason, Silas is evaluated on both a straightforward Easy Benchmark and a deliberately adversarial Hard Benchmark built from semantically similar candidates — the gap between the two is treated as the real signal of embedding quality, not the easy score alone.
| Capability | Example |
|---|---|
| Semantic Search | Find conceptually relevant documents |
| RAG | Retrieve context for language models |
| Knowledge Bases | Search enterprise documentation |
| FAQ Matching | Match questions with answers |
| Similarity Systems | Compare semantic meaning |
| Code Search | Retrieve related programming content |
| Vector Databases | Store and query dense vectors |
| Multilingual AI | Represent text across supported languages |
| Benchmark | Corpus | Queries | Primary Purpose |
|---|---|---|---|
| Easy Embedding Benchmark | Evaluation set | 1,000 | Standard semantic matching |
| Hard Embedding Benchmark | 72,635 documents | 1,000 | Difficult semantic discrimination |
The hard benchmark introduces semantically similar candidates, making it a more demanding test of embedding quality than corpus-level recall alone.
| Metric | Score |
|---|---|
| Recall@1 | 96.70% |
| Recall@5 | 99.90% |
| Recall@10 | 100.00% |
| MRR@10 | 98.15% |
Interpretation: The model performs strongly when the correct semantic match is relatively distinguishable from competing candidates — this reflects typical FAQ-matching and coarse retrieval workloads.
| Parameter | Value |
|---|---|
| Corpus Size | 72,635 documents |
| Evaluation Queries | 1,000 |
| Candidate Environment | Semantically similar documents |
| Primary Metric | Recall@1 |
| Ranking Metric | MRR@10 |
| Metric | Score |
|---|---|
| Recall@1 | 61.40% |
| Recall@5 | 88.30% |
| Recall@10 | 92.90% |
| MRR@10 | 72.68% |
This benchmark is intentionally more difficult because incorrect candidates can be semantically close to the correct document — the kind of near-miss confusion that matters most in production RAG pipelines.
| Metric | Easy | Hard |
|---|---|---|
| Recall@1 | 96.70% | 61.40% |
| Recall@5 | 99.90% | 88.30% |
| Recall@10 | 100.00% | 92.90% |
| MRR@10 | 98.15% | 72.68% |
The gap between the two evaluations is a useful signal of how the model behaves once results get semantically crowded, rather than an artifact of an easy test set.
A detailed failure analysis was run on the hard benchmark results:
| Analysis | Result |
|---|---|
| Queries analyzed | 1,000 |
| Semantic hard negatives | 386 |
| Average positive similarity | 0.6894 |
| Average top-negative similarity | 0.6534 |
| Average separation margin | 0.0360 |
| Potential noisy positives | 0 |
| Potential duplicates | 0 |
Key finding: The average similarity margin between the positive document and the strongest negative candidate was only 0.0360. This indicates the remaining challenge is primarily fine-grained semantic separation, not simply filtering out unrelated content — which directly informs the hard-negative mining plan in the Roadmap.
Silas follows an evaluation-driven development process:
BASE MODEL
│
▼
┌─────────────────┐
│ Baseline Test │
└────────┬────────┘
│
▼
┌─────────────────┐
│ Hard Benchmark │
└────────┬────────┘
│
▼
┌─────────────────┐
│ Failure Analysis│
└────────┬────────┘
│
▼
┌─────────────────┐
│ Hard Negatives │
└────────┬────────┘
│
▼
┌─────────────────┐
│ Fine-Tuning │
└────────┬────────┘
│
▼
┌─────────────────┐
│ Validation │
└────────┬────────┘
│
▼
PRODUCTION MODEL
pip install -U sentence-transformers
from sentence_transformers import SentenceTransformer
model = SentenceTransformer(
"alfotech/silas-embedding-0.6b"
)
texts = [
"Artificial intelligence improves information retrieval.",
"Vector embeddings represent semantic relationships."
]
embeddings = model.encode(
texts,
normalize_embeddings=True
)
print(embeddings.shape)
For retrieval-style workloads, query instructions can describe the intended task:
Instruct: Given a search query, retrieve relevant passages.
Query: How do I optimize transformer inference?
queries = [
"How do I optimize transformer inference?"
]
documents = [
"Quantization, batching, and KV-cache optimization can reduce inference latency.",
"The stock market closed higher after strong earnings reports."
]
query_embeddings = model.encode(
queries,
prompt_name="query",
normalize_embeddings=True
)
document_embeddings = model.encode(
documents,
normalize_embeddings=True
)
scores = model.similarity(
query_embeddings,
document_embeddings
)
print(scores)
Use
prompt_name="query"for the search-query side of asymmetric retrieval and leave documents un-prefixed. For symmetric tasks (e.g. clustering, deduplication), encode both sides the same way.
Silas supports configurable embedding dimensions so storage and latency can be traded against representation capacity without re-encoding your corpus with a different model:
embeddings = model.encode(
["Efficient vectors reduce storage requirements."],
normalize_embeddings=True,
truncate_dim=256
)
Supported range: 32 → 1024 dimensions.
Use larger representations when maximizing representation capacity is important (e.g. hard semantic discrimination), or smaller vectors when storage and throughput are the priority (e.g. large-scale first-pass retrieval).
embeddings = model.encode(
large_text_list,
batch_size=32,
normalize_embeddings=True,
show_progress_bar=True
)
For corpora in the millions of documents, encode in chunks and stream directly into your vector database's bulk-insert API rather than holding all vectors in memory at once.
| Configuration | Recommended Value |
|---|---|
| Sequence Length | 512 |
| Batch Size | 32 |
| Normalization | Enabled |
| Similarity Metric | Cosine |
| Default Dimension | 1024 |
These are recommended starting points — production workloads should be benchmarked using representative data before locking in a configuration.
Silas is a standard sentence-transformers-compatible model, so it can be served with:
Choice of serving stack should be validated against your own latency, throughput, and hardware constraints — figures above are configuration defaults, not deployment benchmarks.
Application
│
▼
Silas Embedding
│
▼
Vector Database
│
┌───┼───────────────┐
▼ ▼ ▼
FAISS Qdrant pgvector
│
▼
Nearest Neighbors
│
▼
AI Application
Silas is intended as the representation layer in semantic search, RAG, knowledge-base retrieval, and similarity-matching systems, primarily where:
Out of scope: Silas does not verify factual correctness, does not perform classification or generation on its own, and should not be used as a sole safety or content-moderation filter — similarity scores reflect semantic closeness, not truth or safety.
Silas is currently evaluated primarily through embedding and semantic-matching experiments. Current limitations include:
For high-stakes applications (legal, medical, financial, safety-critical), validate Silas using domain-specific evaluation datasets and appropriate system-level safeguards rather than relying on the benchmarks above alone.
| Component | Status |
|---|---|
| Base Model Integration | ✅ Complete |
| Baseline Evaluation | ✅ Complete |
| Easy Benchmark | ✅ Complete |
| Hard Benchmark | ✅ Complete |
| Failure Analysis | ✅ Complete |
| Semantic Hard-Negative Discovery | ✅ Complete |
| Retrieval Fine-Tuning | 🔄 Ongoing |
| Extended Blind Evaluation | 🔄 Planned |
| Production Optimization | 🔄 Planned |
Model Quality
Benchmarking
Deployment
| Version | Status | Notes |
|---|---|---|
| v1 | Current | Initial public release; baseline + hard-benchmark results above |
Future releases that materially change benchmark numbers or the recommended production config will be tagged as new versions rather than silently overwriting these results.
Which dimension should I use?
Start at the default 1024 for best hard-case separation. Drop to a smaller truncate_dim (e.g. 256–384) once you've confirmed accuracy holds on your own hard-negative style data — don't shrink dimensions before benchmarking on your corpus.
Do I need the query prompt for every use case?
Only for asymmetric retrieval (short query → long document). For symmetric comparison tasks (dedup, clustering, paraphrase matching), encode both sides without the query prompt.
Why is Recall@1 so much lower on the hard benchmark? Because the hard benchmark's negatives are semantically close to the correct answer by design (see Semantic Analysis) — this is expected and is the metric the roadmap's hard-negative mining work targets directly.
Is this model safe to use as a standalone fact-checker or filter? No — see Intended Use and Bias, Risks & Limitations.
Silas follows an evaluation-first development methodology. The project tracks:
All benchmark values presented above are measured results from the current development evaluation.
@misc{silas_embedding_2026,
title={Silas Embedding 0.6B},
author={Alfo Tech Industries},
year={2026},
publisher={Hugging Face},
url={https://huggingface.co/alfotech/silas-embedding-0.6b}
}
@article{qwen3embedding,
title={Qwen3 Embedding: Advancing Text Embedding and Reranking Through Foundation Models},
author={Zhang, Yanzhao and Li, Mingxin and Long, Dingkun and others},
journal={arXiv preprint arXiv:2506.05176},
year={2025}
}
Apache-2.0
Silas is based on Qwen3-Embedding-0.6B and follows the applicable licensing requirements of the upstream model.