A summary is a valid response, although I will always be hoping for MORE THAN just a summary.
What is a Response?
For the purposes of my class, a response is a very informal assignment that serves a variety of purposes. Responses may serve as informal drafts of sorts for the formal essay assignments. That is, you can express ideas that you may want to explore further in your essays. Most importantly, however, these responses will allow me to see how you reacted to the stories, what interested you (or did not interest you) about them, and what the class can discuss regarding the stories. To that extent, I am hoping for something personal regarding the story. If you want to call it a reaction paper (as in, What was your reaction to this story?), do so.
Having said all that, responses come in many different forms. Just because you can use them to work on your essay skills, it does not mean they have to be in essay form. Again, this is an informal assignment. Just because you can use these to play with ideas for the formal essays, it does not mean they have to be related to the essay assignments in any way. Just because I am hoping for something personal, it does not mean they must be personal.
You may be creative in responses. Feel free to write a different version of the story, perhaps written from a different viewpoint. You may write a different ending of the story. You may write a continuation of the story or a postscript that shows what is happening years later. A response can take the form of a parody of the story, or even a poem.