Standard · v1.2 · corrected specification text v1.2.1

Common Workflow Language

Maintained by Common Workflow Language working group · Software Freedom Conservancy

What it helps you do

CWL supports portable JSON or YAML descriptions of command-line tools and data-intensive workflows, including typed inputs and outputs, requirements, dependencies, conditional steps, and scatter execution.

  • Omics
  • Bioinformatics
  • Computational modeling
  • AI / ML
PlanAcquireHarmonizeExchangeLearn + reuse

01

Where it fits and where it does not

Use these four checks before committing implementation time.

Use it when
Reproducible bioinformatics and scientific workflows that must move across workstations, clusters, clouds, and compatible workflow engines.
Limits
Runner behavior outside the specified execution model can vary, and CWL alone does not freeze containers, reference data, credentials, resource policies, or scientific assumptions.
Best for
Omics and Bioinformatics and Computational modeling and AI / ML teams working across Plan → Harmonize → Exchange → Learn + reuse.
Maturity
EstablishedSuitable for production assessment. Pin the exact release and any implementation profile.

02

See it in the workflow

This view shows the input, the change the standard introduces, and the resulting output.

  1. InputWhat starts

    Omics and Bioinformatics and Computational modeling and AI / ML source data, metadata, and local mappings

  2. CWLWhat changes

    Use CWL as a pinned standard across Plan → Harmonize → Exchange → Learn + reuse

  3. OutputWhat becomes possible

    A handoff the next system or team can validate against the same release

Readiness gateRunner behavior outside the specified execution model can vary, and CWL alone does not freeze containers, reference data, credentials, resource policies, or scientific assumptions.

03

A concrete example

A genomics team validates a pinned CWL v1.2 workflow, container digests, reference checksums, inputs, outputs, and runner conformance before executing it through a WES endpoint.

Why it matters: Makes preprocessing and feature-generation workflows inspectable and portable, while dataset fitness, label validity, leakage controls, and run-level evidence remain separate gates.

04

What it fits with

CWL describes the executable workflow that GA4GH WES can run; BioCompute documents a reviewable analysis; RO-Crate can package workflow assets and run evidence; PROV-O can express provenance.

05

Implementation starter

Start with one bounded handoff. Pin, test, and review it before scaling.

  1. Define one handoff, its accountable owner, and the decision CWL must support.

  2. Pin the exact version and companion artifacts: v1.2 · corrected specification text v1.2.1.

  3. Map one representative input to the required standard artifacts.

  4. Test the result against the canonical source and record every exception.

  5. Preserve the source data, mappings, and review evidence before scaling.

06

Test the main limitation

Risk

Runner behavior outside the specified execution model can vary, and CWL alone does not freeze containers, reference data, credentials, resource policies, or scientific assumptions.

Test

Run one representative end-to-end pilot and record exactly where CWL loses context, needs an extension, or depends on another standard.

Risk

Machine-readable output may still be unfit for analysis or ML.

Test

Test the output for missing context, provenance, terminology alignment, time leakage, and the intended downstream decision. Makes preprocessing and feature-generation workflows inspectable and portable, while dataset fitness, label validity, leakage controls, and run-level evidence remain separate gates.

07

Official resources

Specifications, diagrams, examples, and guides from the organizations that maintain them.

  • Primary sourcev1.2 · corrected specification text v1.2.1

    CWL Workflow Description v1.2.1

    Official publisher or steward guidance for this standard profile.

    Publisher
    Common Workflow Language working group · Software Freedom Conservancy
    Open official source

Next action

Put this profile in context

Compare its role with adjacent standards or place it inside an end-to-end data pathway before choosing an implementation.