Question: If a function relies on `$_SESSION['some_var']` then the header comment out to make that clear. How do you do it? Just as text, or what?

Or even `@param`?

Answer: 
You could maybe use [@uses](http://manual.phpdoc.org/HTMLSmartyConverter/PHP/phpDocumentor/tutorial_tags.uses.pkg.html) to document superglobals
Wow, I never even thought about that. I don't even doc things like that. I would say to just state it in the method detail like

```
/**
 * Takes the some_var session variable and uses it to solve world hunger
 * @return food
 */

```

Makes the most sense to me.

There is @global, but that seems to indicate the creation of a global var. I think @param should only refer to method parameters passed to the method. There is no @note, that I know of.