Document prompt requirement inspection

examples/go-library/prepare/main.go

@@ -36,6 +36,17 @@ func main() {
 	if _, found := view.Explain(configkit.Keys("profiles", "offline-example", "model")); !found {
 		exit(fmt.Errorf("configured profile model was not found"))
 	}
+	requirements, err := engine.InspectRequirements(context.Background(), promptkit.RequirementInspectionRequest{
+		PromptID: "example.prepare",
+	})
+	if err != nil {
+		exit(err)
+	}
+	if !requirements.Complete || len(requirements.Inputs) != 1 ||
+		requirements.Inputs[0].Name != "note" ||
+		requirements.Inputs[0].Kind != promptkit.RequirementRequired {
+		exit(fmt.Errorf("required note input was not discovered before preparation"))
+	}
 
 	prepared, err := engine.Prepare(context.Background(), promptkit.RunRequest{
 		PromptID: "example.prepare",