Tcl-IVR API includes the standard commands and APIs specified in programming guide. It's used mostly for call control and IVR applications. If you are looking for something like execute IOS CLI commands within Tcl then Tcl IVR API won't be able to do that. There is another way to use Tcl script
Cisco IOS Embedded Event Manager (EEM)
http://www.cisco.com/en/US/products/ps6815/products_ios_protocol_group_home.html Have you checked this option ?
Thanks !