Telltale Tool is a game engine developed by Telltale Games, which utilizes the Lua scripting language. It is designed to be portable so that Telltale can release their games on multiple platforms.
The original version was created when Telltale games was formed in 2004,[3] and was originally referred to as the "Telltale Engine and Toolset".[4] The casual poker game Telltale Texas Hold'em was created to test their engine and distribution model, and to ensure that all major bugs were ironed out before the release of their first graphic adventure game, Bone: Out From Boneville.
The Telltale Tool is used for every game released by Telltale Games, however the engine has received several improvements since the initial version. Telltale Games published Hector: Badge of Carnage which also used the Telltale Tool, despite the fact that it was developed by Straandlooper.
(Source: Wikipedia)