Fan-Out - Parallel Execution

examples/05-fanout.halo policies |* parallel

Run independent stages in parallel with |* { ... } All fanout stages complete before the next stage runs

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// ============================================================
// STEP 5: Fan-Out - Parallel Execution
// Learn: Run independent stages in parallel with `|* { ... }`
// All fanout stages complete before the next stage runs
// ============================================================

policy NoProfanity : Block(Profanity)

agent Greeter [gemini-3-1-pro, temp: 0.7]
  requires NoProfanity

pipeline ParallelGreetings(name: String) -> Result:
  name
    // Fan-out: Run two independent prompts in parallel
    |* {
        Greeter.prompt("Write a greeting in English for {{name}}."),
        Greeter.prompt("Write a greeting in Spanish for {{name}}.")
      }
    // Merge results (both greetings now available in context)
    |> System.Print()