Run an installed workflow as a step (workflow composition)

[markuswondrak]

Problem

Workflows orchestrate commands, not other workflows. The 12 built-in step types have no workflow step, and overlays only edit a single base workflow — so a meta-workflow that routes to different workflows has to copy their steps or shell out to specify workflow run opaquely.

Solution Sketch

One custom step type (workflow), written once, that runs any already-installed workflow:

# .specify/workflows/steps/workflow/__init__.py  (+ step.yml with step.type_key: workflow)
class WorkflowStep(StepBase):
    type_key = "workflow"

    def execute(self, config, context):
        cmd = ["specify", "workflow", "run", config["workflow"], "--json"]
        for k, v in config.get("input", {}).items():
            cmd += ["--input", f"{k}={evaluate_expression(v, context)}"]
        proc = subprocess.run(cmd, capture_output=True, text=True, cwd=context.project_root)
        data = json.loads(proc.stdout)          # status: completed | paused | failed
        return StepResult(
            status=StepStatus.COMPLETED if data["status"] == "completed" else StepStatus.FAILED,
            output=data,
        )

Referenced workflows must be installed and are resolved by id only.

Example

steps:
  - id: triage
    type: prompt
    prompt: "Classify the request as 'feature' or 'bug'. Reply with one word."

  - id: route
    type: if
    condition: "{{ steps.triage.output.stdout | contains('bug') }}"
    then:
      - id: run-bug
        type: workflow
        workflow: bug          # installed workflow id
        input: { spec: "{{ inputs.spec }}" }
    else:
      - id: run-speckit
        type: workflow
        workflow: speckit      # installed workflow id
        input: { spec: "{{ inputs.spec }}" }

Question

Is composing workflows this way in scope for core, or would a community step be the preferred route — and are there risks in these approaches I'm missing?

AI-assisted draft: generated by opencode (model: deepseek-v4.1-flash, human-supervised) on behalf of @markuswondrak, who reviewed and posted it.