diff --git a/labscore/cardstack/DynamicCardStack.js b/labscore/cardstack/DynamicCardStack.js
index cbb2bb0..03a03b0 100644
--- a/labscore/cardstack/DynamicCardStack.js
+++ b/labscore/cardstack/DynamicCardStack.js
@@ -15,9 +15,14 @@ const {DISCORD_INVITES} = require("#constants");
  */
 const activeStacks = new WeakMap();
 
+const BUILT_IN_BUTTON_TYPES = Object.freeze({
+  NEXT_PAGE: "next",
+  PREVIOUS_PAGE: "previous"
+})
+
 const DEFAULT_BUTTON_ICON_MAPPINGS = Object.freeze({
-  "next": "button_chevron_right",
-  "previous": "button_chevron_left"
+  [BUILT_IN_BUTTON_TYPES.NEXT_PAGE]: "button_chevron_right",
+  [BUILT_IN_BUTTON_TYPES.PREVIOUS_PAGE]: "button_chevron_left"
 });
 
 const STACK_CACHE_KEYS = Object.freeze({
@@ -397,8 +402,7 @@ class DynamicCardStack {
     //this.lastInteraction = Date.now();
 
     // Built-in Buttons
-    // TODO: derive this from a constant
-    if(["next","previous"].includes(ctx.data.customId)){
+    if(Object.values(BUILT_IN_BUTTON_TYPES).includes(ctx.data.customId)){
       switch(ctx.data.customId){
         case "next":
           return ctx.respond({