Spec Explorer 2010 Release 3.5

Spec Explorer 2010 is a tool that extends Visual Studio for modeling software behavior, analyzing that behavior by graphical visualization, model checking, and generating standalone test code from models.  Behavior is modeled in two ways: by writing rules in C# (with dynamic data-defined state spaces) and by defining model scenarios as action patterns in a regular-expression style.

Spec Explorer 2010 Release 3.5 contains new features, improved documentation, plus over 60 bug fixes.  It runs on the Visual Studio 2010 Professional level product and above.

Spec Explorer Home Page

Oslo Modeling Language Specification

The Microsoft “Oslo” Language Specification is the authoritative source for “M” grammar and syntax.  It contains detailed information about all aspects of the language.

The “Oslo” Modeling Language (commonly referred to as "M") is a language for defining domain models and languages (the latter are often referred to as textual DSLs).  "M" was created to allow developers to efficiently capture their intention in a form that is natural to author but also efficient to store and query using off-the-shelf database technology.

Read more at MSDN