Agentic RAG示例：5个超越简单检索的模式
Agentic RAG是2026年的热词。这里有5个可以照做的具体模式。
Agentic RAG Example 2026: 5 Working Patterns Beyond Simple Retrieval
Agentic RAG means giving the retrieval pipeline agency: the ability to plan, use tools, iterate, and decide. The term became mainstream in 2025 after surveys and frameworks popularized it. Here are five concrete patterns, each with a real example.
Pattern 1: Query Rewriting
Problem: Users ask vague questions; raw retrieval fails. Example: User asks "what about the new iPhone?" The agent rewrites to "iPhone 17 camera specifications 2026" before searching, then also searches "iPhone 17 release date". Tooling: A small LLM call before the retriever; zero graph complexity.
Pattern 2: Retrieve-Grade-Retrieve (self-correction)
Problem: First retrieval misses the answer. Example: Search "LangGraph RAG" returns 5 docs. A grader scores each for relevance to the actual question. All score low - the agent rewrites the query and searches again. Loops until a doc scores above threshold or max 3 attempts. Tooling: LangGraph loop with a grader node (as in the popular "corrective RAG" paper, Yan et al. 2024).
Pattern 3: Multi-Tool RAG
Problem: Knowledge lives in multiple places. Example: A support agent has three tools: vector search on the manual, SQL query on the order database, and web search for recent updates. It plans which tool to call based on the question, and can call several in one turn. Tooling: Tool-calling LLM + LangGraph routing node.
Pattern 4: RAG + Memory
Problem: Follow-up questions lose context. Example: First turn: "What is QLoRA?" Second turn: "How much memory does it need?" The agent carries the conversation state and augments the second retrieval with first-turn context. Tooling: LangGraph checkpointers or an external memory store.
Pattern 5: Self-Ask / Decomposition
Problem: Complex questions need sub-questions. Example: "Compare the licensing of Qdrant and Milvus" decomposes into "Qdrant license?" + "Milvus license?" + "Compare." Each sub-question retrieves separately, then answers combine. Tooling: Agent frameworks with planning nodes (CrewAI, LangGraph, or DSPy).
Choosing the Right Pattern
| Your problem | Start with |
|---|---|
| Vague queries | Pattern 1 (rewriting) |
| Missed answers | Pattern 2 (grade-retry) |
| Multiple data sources | Pattern 3 (multi-tool) |
| Conversational follow-ups | Pattern 4 (memory) |
| Multi-part questions | Pattern 5 (decomposition) |
FAQ
Is agentic RAG worth the complexity? Start with simple RAG. Add agent patterns one at a time when evaluation shows a specific failure mode.
Does it need an agent framework? No - pattern 1 and 5 are plain code; patterns 2-4 benefit from LangGraph or similar state management.
What is the cost overhead? Each loop iteration costs an extra LLM call. Budget for 2-5x token cost vs simple RAG, offset by better answers.
