It is customary that the introductory paragraph should include the thesis statement, a kind of mini-outline for the paper. It tells the reader what the essay is about. The last sentence of this paragraph must also contain a transitional "hook" which moves the reader to the first paragraph of the body of the paper.
Given the previous information, we could conclude that stating all three of the main supporting details to an argument is a constituent of a good introductory paragraph because that would be considered as the thesis statement, which tells the reader what the essay is about.
