similarity-search-patterns
About similarity-search-patterns
A skill covering production patterns for efficient similarity search, from distance metrics and index choices to tuning and evaluation. It supports teams building semantic search, retrieval, or recommendation systems.
Key features
- 01Distance metric selection
- 02Flat, HNSW, and IVF+PQ index guidance
- 03Recall and speed tuning
- 04Hybrid semantic and keyword search
- 05Search quality monitoring
Use cases
- 01Build semantic search systems
- 02Implement RAG retrieval
- 03Create recommendation engines
- 04Reduce search latency at scale
Install
Copy the command and run it in a terminal.
npx skills add https:/ / github.com/ wshobson/ agents --skill similarity-search-patternsAfter installing, type/similarity-search-patternsin Claude Code to confirm it loaded.
Bundled filesreferences/details.md
Details
From the project READMESimilarity Search Patterns
Patterns for implementing efficient similarity search in production systems.
When to Use This Skill
- Building semantic search systems
- Implementing RAG retrieval
- Creating recommendation engines
- Optimizing search latency
- Scaling to millions of vectors
- Combining semantic and keyword search
Core Concepts
1. Distance Metrics
| Metric | Formula | Best For | | ------------------ | ------------------ | --------------------- | --- | -------------- | | Cosine | 1 - (A·B)/(‖A‖‖B‖) | Normalized embeddings | | Euclidean (L2) | √Σ(a-b)² | Raw embeddings | | Dot Product | A·B | Magnitude matters | | Manhattan (L1) | Σ | a-b | | Sparse vectors |
2. Index Types
┌─────────────────────────────────────────────────┐
│ Index Types │
├─────────────┬───────────────┬───────────────────┤
│ Flat │ HNSW │ IVF+PQ │
│ (Exact) │ (Graph-based) │ (Quantized) │
├─────────────┼───────────────┼───────────────────┤
│ O(n) search │ O(log n) │ O(√n) │
│ 100% recall │ ~95-99% │ ~90-95% │
│ Small data │ Medium-Large │ Very Large │
└─────────────┴───────────────┴───────────────────┘
Templates and detailed worked examples
Full template library and detailed worked examples live in references/details.md. Read that file when you need the concrete templates.
Best Practices
Do's
- Use appropriate index - HNSW for most cases
- Tune parameters - ef_search, nprobe for recall/speed
- Implement hybrid search - Combine with keyword search
- Monitor recall - Measure search quality
- Pre-filter when possible - Reduce search space
Don'ts
- Don't skip evaluation - Measure before optimizing
- Don't over-index - Start with flat, scale up
- Don't ignore latency - P99 matters for UX
- Don't forget costs - Vector storage adds up