public JsonNode toJson(ObjectMapper mapper) {
        ObjectNode root = mapper.createObjectNode();
        // Template-specific fields at the top when this is a template definition
        if (isTemplate) {
            root.put("isTemplate", true);
            root.put("templateVersion", templateVersion != null ? templateVersion : "2.0");
        }
        root.put("baseUrl", baseUrl);
        root.put("timeoutMs", timeoutMs);
        root.put("verifySsl", verifySsl);
        if (!headers.isEmpty()) {
            ObjectNode h = mapper.createObjectNode();
            headers.forEach(h::put);
            root.set("headers", h);
        }
        root.set("auth", auth.toJson(mapper));