Researcher is Copilot's specialist for multi-step research. Ask it a specific question and it gathers from files, emails, meetings and chats you can access, plus the web if you allow it, then returns a report with headings, cited sources, key findings and next steps. It may ask clarifying questions first, including whether to search work content, the web or both.
Depth takes time: simple questions usually take under five minutes, complex ones ten to forty-five. Researcher and Analyst share a cap of twenty-five queries per user per month, so save it for questions that need several sources weighed. It is a first-party agent: you cannot edit its instructions, and it does not write files back to a folder the way Claude Cowork does.