In short. OpenAI requires web search citations shown to end users to be clearly visible and clickable inline citations.
Definition: An inline source citation is a source reference attached to text returned by an OpenAI web search integration. OpenAI requires citations for web results shown to end users to be clearly visible and clickable in the user interface.
Key facts
- OpenAI's web search documentation says that model responses include inline citations for URLs found in web search results by default.
- The same guide says a
url_citationannotation contains the cited source's URL, title and location in the response. - OpenAI's citation-formatting guide recommends defining the marker syntax, citation placement, citation conditions, multiple-source behavior, forbidden formats and the response to missing support when you write citation instructions.
- OpenAI documents placement after punctuation, paragraph-end or inline placement for long paragraphs, and separation from markdown code fences.
What must the interface show?
The requirement applies when an integration displays web results or information contained in web results to end users. OpenAI's web search guide states that inline citations must be clearly visible and clickable in the user interface. A plain source list that cannot be opened from the citation does not match that documented requirement.
The API response supplies the material an interface needs to connect displayed text to a source. In the Chat Completions response shape, the documentation names message.content as the model text with inline citations and annotations as the list of cited URLs. For web search responses, the url_citation object supplies the URL and title, together with the start and end character positions where the source was used.
{
"type": "url_citation",
"url_citation": {
"end_index": 985,
"start_index": 764,
"title": "Page title...",
"url": "https://..."
}
}
The character positions let an integration associate a citation with the relevant portion of the response. The cited URL and title provide source details for the clickable element.
Where should an inline citation be placed?
OpenAI's citation-formatting guide says to place citations at the end of a paragraph, or inline when a paragraph is long, unless the user requests a specific placement. It also says citations must come after punctuation. This guidance concerns the citation's position in the generated response, while the web search guide sets the interface requirement that the displayed citation is visible and clickable.
The same guide says citations must not be placed inside markdown bold, italics or code fences because they will not display correctly. It also says citations must not be grouped together only at the end of the response. An integration therefore needs to preserve the citation markers in readable response text and render the source link outside markdown constructs that would prevent the citation from displaying correctly.
How should an integration handle multiple sources?
The citation-formatting guide recommends that a custom citation instruction define how to cite multiple supports. It gives a format that emits multiple citation markers for multiple sources and says each marker should refer to a source that appears in the provided context.
For a web search integration, the response annotations identify cited URLs, and the interface can use each annotation's source URL and title when constructing clickable inline citations. OpenAI's web search documentation also distinguishes the inline citations in the model response from the complete list of URLs available through the sources field. The complete list is separate from the citations shown in the answer.
Related terms
FAQ
Does OpenAI require a particular icon or color for the citation?
The cited documentation requires citations to be clearly visible and clickable. It does not specify an icon, color or hover treatment.
Can a citation appear only in a source list below the answer?
OpenAI documents inline citations in the model response and requires them to be visible and clickable when web results or information from them is shown to end users. A separate source list does not satisfy that inline display requirement by itself.
What data should the interface read from the response?
Read the response text and its URL citation annotations. The documented annotation includes the source URL, title and the character positions where the source was used.
Sources
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