# Common Workflow Language Specifications, v1.0.2

The CWL specifications are divided up into several documents.

The [User Guide](http://www.commonwl.org/user_guide/) provides a gentle
introduction to writing CWL command line tools and workflows.

The [Command Line Tool Description Specification](CommandLineTool.html)
specifies the document schema and execution semantics for wrapping and
executing command line tools.

The [Workflow Description Specification](Workflow.html) specifies the document
schema and execution semantics for composing workflows from components such as
command line tools and other workflows.

The
[Semantic Annotations for Linked Avro Data (SALAD) Specification](SchemaSalad.html)
specifies the preprocessing steps that must be applied when loading CWL
documents and the schema language used to write the above specifications.