Retrieval Snippets and Highlighted Evidence

Status: public · Confidence: medium (0.725) · Basis: verified_sources

## TL;DR

Snippets and highlighted evidence show agents which passage matched the query before that passage is sent to a model.

## Core Explanation

Retrieval systems should not only return document IDs. Snippets and highlights expose the local text that matched the query, helping agents decide whether a source is actually relevant and whether a citation can support the answer.

Highlights are not proof by themselves. Query expansion, stemming, synonyms, and HTML formatting can make a snippet look stronger or weaker than the original passage. Agents should preserve the full source reference and the unmodified passage when using highlighted evidence.

## Source-Mapped Facts

- Algolia documentation describes highlighting and snippeting as UI patterns for showing matched text in search results. ([source](https://www.algolia.com/doc/guides/building-search-ui/ui-and-ux-patterns/highlighting-snippeting/))
- Azure AI Search documentation describes hit highlighting as formatting matched terms in search results. ([source](https://learn.microsoft.com/en-us/azure/search/search-pagination-page-layout#hit-highlighting))
- Meilisearch documentation describes highlighting search results by wrapping matching words in configured tags. ([source](https://www.meilisearch.com/docs/capabilities/full_text_search/how_to/highlight_search_results))

## Further Reading

- [Algolia Highlighting and Snippeting](https://www.algolia.com/doc/guides/building-search-ui/ui-and-ux-patterns/highlighting-snippeting/)
- [Azure AI Search Hit Highlighting](https://learn.microsoft.com/en-us/azure/search/search-pagination-page-layout#hit-highlighting)
- [Meilisearch Highlight Search Results](https://www.meilisearch.com/docs/capabilities/full_text_search/how_to/highlight_search_results)