The Callisto annotation tool was developed to support linguistic annotation of textual sources for any Unicode-supported language.

Callisto has been built with a modular design, and utilizes standoff-annotation, allowing for unique tag-set definitions and domain dependent interfaces. Standoff-annotation support, provided by jATLAS, allows for nearly any annotation task to be represented.

The modular design of Callisto allows it to be extended with user interface components specific to a domain. Default tag editing capabilities are provided through a highlighted text display, and tag attribute tables. As domain specific extension components are developed, they may be integrated into the core of Callisto, to become part of the standard suite of available components.

Callisto is written in Java, taking advantage of it’s portability, and language support.