API glossary

Source attribution

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Source attribution is the practice of identifying and crediting the original sources behind a piece of information, so a reader can see where a claim originated. In AI search and answer engines, it means pairing generated answers with citations (links or references back to the specific pages and passages the answer draws on) rather than presenting conclusions with no traceable origin.

In short: source attribution shows where an answer’s information came from—the citations and links that let you trace a claim back to its source.

How source attribution works

Attribution depends on carrying a thread from each source through to each statement:

  1. Retrieve with metadata: The system fetches supporting documents or results, each carrying its source metadata: a URL, a title, and the passage used.
  2. Track the link: As the model generates an answer, it keeps track of which retrieved passage supports which claim.
  3. Cite the claim: The answer is annotated with references: footnote markers, source cards, or inline links that tie statements back to their sources.
  4. Expose for verification: The user or application can trace each citation to the original to confirm a claim or read further.

The defining requirement is an unbroken chain from source to statement: attribution is only trustworthy if each cited source actually supports the claim attached to it. Otherwise there can be misattribution, which is often worse than no citation at all.

Source attribution vs. grounding and citation lists

  • Grounding connects a model’s output to retrieved sources as a way to reduce hallucinations; source attribution surfaces which specific source backs each claim. Grounding can happen silently, but trustworthy attribution requires it as a foundation.
  • A bibliography lists the sources used overall; source attribution ties specific claims to specific passages, ideally at the sentence level.
  • A high retrieval score says a source looked relevant; source attribution says the answer actually drew on it; relevance is not the same as use.

Where source attribution matters

  • End-user trust: In AI answer engines and the AI overviews on a search engine results page, visible citations let people verify claims, judge credibility, and click through, which is also how publishers get credit and traffic.
  • Reducing hallucinations: Requiring each claim to point at a real source makes ungrounded, fabricated statements easier to catch.
  • RAG pipelines: In RAG, attribution carries source URLs and titles from the retrieval step through to the final answer, so each claim can be traced back to the passage it came from.
  • Developer APIs: Some APIs return structured citation metadata alongside generated answers, including the exact sentences used, making it easier to surface attributions in a downstream application.
  • Search APIs as the source of truth: A search API returns each result with its URL, title, and snippet, which is the raw material that attribution is built from: no source metadata in, no citations out.

Source attribution is what turns an AI answer from “trust me” into “check for yourself,” which can be the difference between an opaque response and a verifiable one.

Citation, grounding, hallucination, retrieval-augmented generation (RAG), AI answer engine, SERP features, AI Overview, retrieval score, answer engine optimization (AEO), search API.