Cooking: Weekly meal plan that never includes your allergens

examples/66-meal-planner.halo policies |<> loops

Plans meals from what's in the pantry. Allergens are checked in code, not just asked for in the prompt: a grep over the plan, and if it finds one, |<> loop sends the planner back to fix it. The plan's shopping list can feed 62-shopping-restock.

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// ============================================================
// Cooking: Weekly meal plan that never includes your allergens
// ============================================================
// Plans meals from what's in the pantry. Allergens are checked in
// code, not just asked for in the prompt: a grep over the plan, and
// if it finds one, |<> loop sends the planner back to fix it.
// The plan's shopping list can feed 62-shopping-restock.
// ============================================================

policy Budget : MaxSpend(0.10)
policy Shape  : Require(JSON)

tool Shell : Bash()

schema MealPlan {
  meals: Array<Object>
  shopping_list: Array<String>
}

agent Chef [anthropic/claude-haiku-4-5, temp: 0.5]
  system """
    You plan simple, varied home meals. Use pantry items first.
    Answer with JSON: {"meals": [{"day": "Mon", "dish": "...", "ingredients": ["..."]}], "shopping_list": ["..."]}
  """
  requires Budget, Shape

pipeline PlanMeals(pantry: List, diet: String, allergens: String, days: Number) -> MealPlan:
  pantry
    // 1. Plan the week (on a retry, the input is the allergen check that failed)
    |> Chef.plan(
         "Plan {{days}} dinners. Diet: {{diet}}. Never use: {{allergens}}.",
         "Pantry: {{pantry}}"
       ) as plan

    // 2. Check in code: grep exits 0 when an allergen appears anywhere in the plan
    //    (pipefail, so the exit code is grep's and not sort's)
    |> Shell.run(command: "set -o pipefail; echo {{plan}} | grep -i -o -E {{allergens}} | sort -u") as allergen_check
    |<> loop(Chef, "context.data.allergen_check.exitCode == 0", max: 3) as replans

    // 3. The checked plan
    |> System.Pick(context.data.plan, fields: ["meals", "shopping_list"])