diff --git a/src/static/js/Changeset.js b/src/static/js/Changeset.js
index f92703851..5f3c0b60b 100644
--- a/src/static/js/Changeset.js
+++ b/src/static/js/Changeset.js
@@ -42,15 +42,15 @@ exports.error = function error(msg) {
 };
 
 /**
- * This method is user for assertions with Messages 
- * if assert fails, the error function called.
+ * This method is used for assertions with Messages 
+ * if assert fails, the error function is called.
  * @param b {boolean} assertion condition
  * @param msgParts {string} error to be passed if it fails
  */
 exports.assert = function assert(b, msgParts) {
   if (!b) {
     var msg = Array.prototype.slice.call(arguments, 1).join('');
-    exports.error("exports: " + msg);
+    exports.error("Failed assertion: " + msg);
   }
 };
 
@@ -281,7 +281,7 @@ exports.checkRep = function (cs) {
 
   assem.endDocument();
   var normalized = exports.pack(oldLen, calcNewLen, assem.toString(), charBank);
-  exports.assert(normalized == cs, normalized, ' != ', cs);
+  exports.assert(normalized == cs, 'Invalid changeset (checkRep failed)');
 
   return cs;
 }
@@ -1296,7 +1296,7 @@ exports.compose = function (cs1, cs2, pool) {
   var unpacked2 = exports.unpack(cs2);
   var len1 = unpacked1.oldLen;
   var len2 = unpacked1.newLen;
-  exports.assert(len2 == unpacked2.oldLen, "mismatched composition");
+  exports.assert(len2 == unpacked2.oldLen, "mismatched composition of two changesets");
   var len3 = unpacked2.newLen;
   var bankIter1 = exports.stringIterator(unpacked1.charBank);
   var bankIter2 = exports.stringIterator(unpacked2.charBank);
@@ -2010,7 +2010,7 @@ exports.follow = function (cs1, cs2, reverseInsertOrder, pool) {
   var unpacked2 = exports.unpack(cs2);
   var len1 = unpacked1.oldLen;
   var len2 = unpacked2.oldLen;
-  exports.assert(len1 == len2, "mismatched follow");
+  exports.assert(len1 == len2, "mismatched follow - cannot transform cs1 on top of cs2");
   var chars1 = exports.stringIterator(unpacked1.charBank);
   var chars2 = exports.stringIterator(unpacked2.charBank);
 
@@ -2190,7 +2190,7 @@ exports.composeWithDeletions = function (cs1, cs2, pool) {
   var unpacked2 = exports.unpack(cs2);
   var len1 = unpacked1.oldLen;
   var len2 = unpacked1.newLen;
-  exports.assert(len2 == unpacked2.oldLen, "mismatched composition");
+  exports.assert(len2 == unpacked2.oldLen, "mismatched composition of two changesets");
   var len3 = unpacked2.newLen;
   var bankIter1 = exports.stringIterator(unpacked1.charBank);
   var bankIter2 = exports.stringIterator(unpacked2.charBank);