Citation extraction
Citation extraction is the technique of attaching source URLs to LLM-generated claims — critical for AI search products to be trustworthy and to give users a way to verify generated content.
Generative AI without citations is a black box; users can't verify, can't follow up, can't trust. Citation extraction makes the model emit source URLs alongside generated text, either inline (`The capital is Paris [^1]`) or as a structured `citations` field. Implementations: (1) constrained decoding to force citation tokens, (2) post-hoc retrieval matching generated claims to retrieved chunks (BM25 / vector / NLI), (3) tool-use protocols where the search tool returns sources the model must reference. Production leaders: Perplexity, ChatGPT Search, Claude with web search, Gemini AI Overview — all attach citations. Quality matters: a citation that doesn't support the claim is worse than no citation. [[grounding]] is the broader practice this fits into.
When to use citation extraction
- AI search products.
- Anything where the user needs to verify claims.
Common mistakes
- Attaching the search tool's first result regardless of relevance — citations don't support claims.
- Skipping citation in B2C 'just give the answer' products — trust collapses on first hallucination.
FAQ
What is citation extraction?
Citation extraction is the technique of attaching source URLs to LLM-generated claims — critical for AI search products to be trustworthy and to give users a way to verify generated content.
When should I use citation extraction?
AI search products. Anything where the user needs to verify claims.
What are the most common mistakes with citation extraction?
Attaching the search tool's first result regardless of relevance — citations don't support claims. Skipping citation in B2C 'just give the answer' products — trust collapses on first hallucination.
Related terms
- Grounding — Grounding is any technique that ties a language model's output to verifiable sources — retrieved documents, tool results, structured data — instead of pure memory.
- AI search engine — An AI search engine answers a user's query by retrieving relevant web sources and synthesising a cited answer with a language model — the category that includes Perplexity, ChatGPT Search, Claude with web, and Gemini AI Overviews.
- Web retrieval tool — A web retrieval tool is the agent-callable API that fetches live web content for LLMs — Tavily, Exa, Serper, Brave Search API, Perplexity API are 2026 leaders, used as the 'web search' function in tool-use loops.
Last updated: 2026-06-01. Raw markdown: https://promtable.com/glossary/citation-extraction.md.