The extension will auto-complete summary tags, parameters, and optionally return tags after typing a "///" on the first line inside a function's body for vsdoc comments.
Here are some nice references for the basic syntax of vsdocs:
For JSDoc comments, parameter tags will be added as well as a return tag after typing "/**" on the line above a function header.
Type decoration will be added to TypeScript parameters in function comments when the types have been included in the function header.
This extension can be installed for Visual Studio 2012-2015 here.
This extension can be installed for Visual Studio 2010 SP1 here.