hybrid-search-implementation

# Hybrid Search Implementation Patterns for combining vector similarity and keyword-based search. ## When to Use This Skill - Building RAG systems with improved recall - Combining semantic understanding with exact matching - Handling queries with specific terms (names, codes) - Improving search for domain-specific vocabulary - When pure vector search misses keyword matches ## Core Concepts ### 1. Hybrid Search Architecture ``` Query → ┬─► Vector Search ──► Candidates ─┐ │ │ └─► Keyword Search ─► Candidates ─┴─► Fusion ─► Results ``` ### 2. Fusion Methods | Method | Description | Best For | | ----------------- | ------------------------ | --------------- | | **RRF** | Reciprocal Rank Fusion | General purpose | | **Linear** | Weighted sum of scores | Tunable balance | | **Cross-encoder** | Rerank with neural model | Highest quality | | **Cascade** | Filter then rerank | Efficiency | ## 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 - **Tune weights empirically** - Test on your data - **Use RRF for simplicity** - Works well without tuning - **Add reranking** - Significant quality improvement - **Log both scores** - Helps with debugging - **A/B test** - Measure real user impact ### Don'ts - **Don't assume one size fits all** - Different queries need different weights - **Don't skip keyword search** - Handles exact matches better - **Don't over-fetch** - Balance recall vs latency - **Don't ignore edge cases** - Empty results, single word queries