together

The together step executes multiple child steps concurrently. All steps in the block run in parallel; the block completes when all steps finish (or one fails, depending on the error strategy).

Syntax

together fetch_all
  ask classify_email using "anthropic:claude-haiku-4-5"
    with task
      "Classify this email."
    returns
      category as text

  ask extract_entities using "anthropic:claude-haiku-4-5"
    with task
      "Extract named entities from this email."
    returns
      entities as list

  launch check_history
    from: "@mashin/actions/http/get"
    with task
      url: "https://api.example.com/history"

How it works

1. All child steps are dispatched concurrently
2. Each step runs through the normal governance pipeline independently
3. The together block waits for all steps to complete
4. Results from all steps are available as steps.{child_name}.{field}
5. If any step fails and no on failure handler is specified, the entire block fails

Governance

Each child step within together is individually governed. A together block does not bypass governance for any of its children.

Cost implications

Parallel execution may increase cost per unit time (multiple LLM calls running simultaneously) but reduces total wall-clock time.

Step type

together steps have step type :call in the execution trace. Child steps retain their own types (:reason, :call, etc.).

See also

• for each — sequential iteration
• launch — invoke another machine
• on failure — error handling