When I chat with a single file, I want Chief to stay focused on just that file

I uploaded a file to my Project and clicked the Chat button on that specific file, expecting to have a focused conversation about its contents. Instead, Chief pulled in all of the other files in my Project as context for the conversation — not just the one I selected.

I'd like Chief to scope the chat session to the file I initiated it from, so I can ask targeted questions about a single document without unrelated files influencing the responses.