CWL Loader documentation

cwl_loader helps load CWL documents into cwl-utils object models, normalize references, resolve imported workflow steps, and serialize the result back to YAML.

Install it with:

pip install cwl-loader

The documentation is organized according to the Diataxis convention:

Need	Section	Start here
Learn by following a guided path	Tutorials	First steps with CWL Loader
Solve a specific task	How-to guides	Load and serialize CWL
Look up the Python API	Reference	API reference
Understand concepts and design choices	Explanation	The loading model

What CWL Loader does

CWL Loader can read CWL from local files, URLs, text streams, strings, and Python mappings. It can update older CWL documents to v1.2, parse them with cwl-utils, dereference external steps[].run imports, validate that workflow steps point to available processes, and write the resolved document as YAML.

Use the Python API when embedding this behavior in an application.

The bundle CLI has moved

The cwl-loader bundle command is no longer part of CWL Loader. For command-line bundling, use Transpiler Mate.