Citations in Web search: some annotations URLs not appear in the sources list in Web Search API?

API
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1

Hi everyone,

I’ve been experimenting with the web search tool and noticed something odd about how the sources field behaves.

According to the OpenAI documentation, the sources field should return:

“the complete list of URLs the model consulted when forming its response.”

However, in practice, I’m seeing cases where some URLs cited inline do not appear in the sources list. This seems inconsistent — I’d expect every cited URL to be included among the consulted sources.

Is this a known issue or expected behavior?
And is there a way to ensure that all URLs appearing in annotations are also included in sources.

For context, I’m using gpt-4.1-mini with no reasoning effort:

response = self.client.responses.create(
    model="gpt-4.1-mini",
    tools=[{"type": "web_search"}],
    tool_choice="auto",
    include=["web_search_call.action.sources"],
    input=user_content
)

Thanks in advance!