Extract Citation

Extract the relevant excerpts from a tool_result that support a citation.

Given:

• tool_result: The full data returned by a tool call
• citation_id: The citation number (e.g., 1 for [1])
• text_with_citation: The text that cites this data (e.g., "There are 3 errors [1]")

Returns:

• excerpts: List of relevant chunks from tool_result that support the citation