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Concept card · Retrieval & Grounding
Query rewriting turns a follow-up question into a search query that stands on its own.
Turning a follow-up question into a search query that stands on its own.
Oct 18: First card. The picture turns a follow-up into a question you could search with no earlier message. Sources are LlamaIndex's chat engine guide and Azure AI Search's query rewrite guide. Azure marks that feature preview.
A support thread rarely repeats the subject. The next message is "What about weekends?" LlamaIndex's chat engine guide describes condense_question as looking at the chat history and rewriting the user message into a query for the index. Azure AI Search's query rewrite guide describes a different pass: the service sends the search text to a generative model and retrieves with the original query plus the alternatives. Microsoft marks that feature preview, and says preview features are not recommended for production. The picture is the follow-up case. It does not call either API.
The rewrite is another model call before search. Azure's guide says the service sends the query to a generative model. LlamaIndex's condense-question mode also calls a model to rewrite, then queries the index. This card does not add a price for that call.
A follow-up that says "weekends" does not name the product or the policy. A standalone question can. Azure's guide says its rewrite can correct typos and expand a query with synonyms. This card does not claim every rewrite is a better query.
Azure's guide says the rewritten queries might not keep every exact term from the original, which matters when the query is a product code. A rewrite can also search for a subject the user did not ask about.
Take the last two messages from a real support thread. Write the follow-up as a question someone could paste into search with no earlier message. If it still says "that" or "it," it is not ready.
Searching the follow-up as typed. "What about weekends?" does not say which product, or that the subject is support hours.
The user asked when weekday support is open, then asked "What about weekends?" What should retrieval search?
Support-docs answer bot uses this concept in one build. The set on this tab is still the note below.
Coming soon. One follow-up from the support-docs answer bot, rewritten so the hours doc can match, with the original wording kept beside it.
Coming soon. How LlamaIndex condenses a chat turn, and how Azure's preview rewrite adds alternatives. Azure says not to send the debug flag in production.