`rake routes` will output the routes and paths. Appending _path or _url to the path will generate appropriate methods.

Sure. But that still doesn't tell me exactly which arguments they take. Or give me an opportunity to debug the code when it doesn't do as I expect. I realise that it just-works (tm). It's when it doesn't, it gets problematic.

It's actually pretty easy to tell the parameters they take if you look at the url for the route.

For:

    story GET   /story/:id(.:format)  story#show

You get

    story_path(id)
    story_path(id, format)
    story_url(id)
    story_url(id, format)

In practice it doesn't cause as many problems as you think, even in large applications.