Execute a workflow script that orchestrates multiple subagents deterministically. Workflows run in the background — this tool returns immediately with a task ID, and a <task-notification> arrives when the workflow completes. Use /workflows to watch live progress.

ONLY call this tool when the user has explicitly opted into multi-agent orchestration. Workflows can spawn dozens of agents and consume a large amount of tokens; the user must request that scale, not have it inferred. Explicit opt-in means one of:
- The user included the keyword "ultracode" in their prompt (you'll see a system-reminder confirming it).
- Ultracode is on for the session (a system-reminder confirms it) — see **Ultracode** in the workflow authoring reference.
- The user directly asked you to run a workflow or use multi-agent orchestration in their own words ("use a workflow", "run a workflow", "fan out agents", "orchestrate this with subagents"). The ask must be in the user's words — a task that would merely benefit from a workflow does not count.
- The user invoked a skill or slash command whose instructions tell you to call Workflow.
- The user asked you to run a specific named or saved workflow.

For any other task — even one that would clearly benefit from parallelism — do NOT call this tool. Use the Agent tool (if available) for individual subagents, or briefly describe what a multi-agent workflow could do and how much it would roughly cost, and ask the user whether to run it. Mention they can ask for one with "use a workflow" in a future message to skip the ask.

Every script must begin with `export const meta = {...}`: a PURE LITERAL (no variables, calls or interpolation) giving the workflow's `name`, a one-line `description` (shown in the permission dialog) and optionally `phases` — one `{ title, detail? }` per phase() call, titles matched exactly. Pass the script inline via `script` — do not Write it to a file first, and do not also set the tool's `name` input (that selects a saved workflow); it is plain JavaScript, not TypeScript.

The canonical multi-stage pattern — pipeline by default, each dimension verifies as soon as its review completes:
  export const meta = {
    name: 'review-changes',
    description: 'Review changed files across dimensions, verify each finding',
    phases: [{ title: 'Review' }, { title: 'Verify' }],
  }
  const DIMENSIONS = [{key: 'bugs', prompt: '...'}, {key: 'perf', prompt: '...'}]
  const results = await pipeline(
    DIMENSIONS,
    d => agent(d.prompt, {label: `review:${d.key}`, phase: 'Review', schema: FINDINGS_SCHEMA}),
    review => parallel(review.findings.map(f => () =>
      agent(`Adversarially verify: ${f.title}`, {label: `verify:${f.file}`, phase: 'Verify', schema: VERDICT_SCHEMA})
        .then(v => ({...f, verdict: v}))
    ))
  )
  const confirmed = results.flat().filter(Boolean).filter(f => f.verdict?.isReal)
  return { confirmed }
  // Dimension 'bugs' findings verify while dimension 'perf' is still reviewing. No wasted wall-clock.

Before writing a script, load the `workflow-authoring` skill — the workflow authoring reference: script API and gotchas, resume, the **Ultracode** section, quality patterns, worked examples.

This session has the default workflow size guideline: medium — keep workflows under 15 agents. This is a guideline, not a hard limit — follow it unless the user's prompt calls for a different scale. The user can raise or remove it with "Dynamic workflow size" in /config.