Table of Contents
RAG is more than calling LangChain with default settings. A real RAG architect makes dozens of decisions that affect accuracy, latency, and cost. Here's how to evaluate candidates on full-stack RAG architecture.
Retrieval Architecture
Legal: semantic boundaries (paragraphs, sections). Chat logs: by conversation turn. Code: by function or class. Discuss trade-offs of chunk size.
Vector search (semantic). Keyword search (exact terms). Hybrid (both). Re-ranking (post-process). Multi-query (multiple searches combined).
Generation Architecture
System prompt emphasizing 'only answer from context'. Few-shot examples. Format constraints (JSON, XML). Include 'context not found' fallback.
Smaller: cost-sensitive, high volume, simpler domain. GPT-4: complex reasoning, when accuracy matters most, lower volume.
Evaluation Framework
Retrieval: recall@k, MRR, NDCG. Generation: answer correctness, faithfulness, answer relevance. End-to-end: user feedback, A/B tests.
LLM generates answer not supported by retrieved context. Detect with LLM-as-judge, NLI models, or checking if answer contradicts context.
What Strong RAG Architects Explain Naturally
- ✦ Chunking trade-offs
- ✦ Embedding model selection criteria
- ✦ Hybrid search architecture
- ✦ Caching strategies
- ✦ Multi-tenant data isolation
- ✦ Cost versus accuracy trade-offs
Production Considerations
Re-index updated documents. Version vector DB. Handle deletions. Real-time vs batch updates - trade-offs.
Smaller embedding model. Faster vector DB (HNSW indexing). Cache frequent queries. Use smaller LLM. Parallelize retrieval and generation.
Candidate Evaluation Rubric
Retrieval
Strong Candidate:
Can explain multiple retrieval approaches
Generation
Strong Candidate:
Designs grounded prompts
Evaluation
Strong Candidate:
Uses measurable metrics
Operations
Strong Candidate:
Discusses monitoring and updates
Scaling
Strong Candidate:
Understands latency and cost optimization
Assess Full-Stack RAG Skills
RAG architecture requires retrieval, generation, evaluation, and production skills. Offline Pixel pre-vets RAG engineers on all these dimensions. Raise a request, talk to candidates, fund the project, and approve payment when the work is done.
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