diff --git a/src/kiri-mode/cam/client.js b/src/kiri-mode/cam/client.js
index 2f39fc98..71c38d72 100644
--- a/src/kiri-mode/cam/client.js
+++ b/src/kiri-mode/cam/client.js
@@ -95,6 +95,7 @@ CAM.init = function(kiri, api) {
     });
 
     api.event.on("settings.saved", (settings) => {
+        validateTools(settings.tools);
         current = settings;
         let proc = settings.process;
         let hasTabs = false;
@@ -117,6 +118,7 @@ CAM.init = function(kiri, api) {
     api.event.on("settings.load", (settings) => {
         func.opRender();
         if (!isCamMode) return;
+        validateTools(settings.tools);
         restoreTabs(api.widgets.all());
     });
 
@@ -1228,6 +1230,23 @@ function unselectTraces(widget, skip) {
     }
 }
 
+function validateTools(tools) {
+    if (tools) {
+        let max = 0;
+        for (let t of tools) {
+            if (Number.isInteger(t.number)) {
+                max = Math.max(max, t.number);
+            }
+        }
+        for (let t of tools) {
+            if (!Number.isInteger(t.number)) {
+                t.number = ++max;
+                console.log('added tool #', t);
+            }
+        }
+    }
+}
+
 function addbox() { return FDM.addbox(...arguments)};
 function delbox() { return FDM.delbox(...arguments)};