diff --git a/generate/input/descriptor.json b/generate/input/descriptor.json
index d33298c30..bccbbb841 100644
--- a/generate/input/descriptor.json
+++ b/generate/input/descriptor.json
@@ -2529,19 +2529,22 @@
       "functions": {
         "git_tree_entry_byid": {
           "return": {
-            "ownedByThis": true
+            "ownedByThis": true,
+            "selfFreeing": false
           }
         },
         "git_tree_entry_byindex": {
           "jsFunctionName": "_entryByIndex",
           "return": {
-            "ownedByThis": true
+            "ownedByThis": true,
+            "selfFreeing": false
           }
         },
         "git_tree_entry_byname": {
           "jsFunctionName": "_entryByName",
           "return": {
-            "ownedByThis": true
+            "ownedByThis": true,
+            "selfFreeing": false
           }
         },
         "git_tree_entrycount": {
@@ -2562,6 +2565,21 @@
         "git_treebuilder_filter": {
           "ignore": true
         },
+        "git_treebuilder_get": {
+          "return": {
+            "selfFreeing": false,
+            "ownedByThis": true
+          }
+        },
+        "git_treebuilder_insert": {
+          "isAsync": false,
+          "args": {
+            "out": {
+              "selfFreeing": false,
+              "ownedByThis": true
+            }
+          }
+        },
         "git_treebuilder_write": {
           "args": {
             "id": {
diff --git a/test/tests/treebuilder.js b/test/tests/treebuilder.js
index 5e1ce6263..c7ef01f43 100644
--- a/test/tests/treebuilder.js
+++ b/test/tests/treebuilder.js
@@ -5,10 +5,14 @@ var promisify = require("promisify-node");
 var readDir = promisify(fs.readdir);
 var local = path.join.bind(path, __dirname);
 
+var leakTest = require("../utils/leak_test");
+
 describe("TreeBuilder", function(){
 
     var Git = require("../../");
     var reposPath = local("../repos/workdir");
+    var oid = "111dd657329797f6165f52f5085f61ac976dcf04";
+
     //setup test repo each test
     beforeEach(function() {
       var test = this;
@@ -76,4 +80,19 @@ describe("TreeBuilder", function(){
         return Git.Tree.lookup(test.repo, newTreeEntry.oid());
       });
     });
+
+    it("does not leak inserts", function() {
+      var test = this;
+
+      // The underlying C++ git_tree_entry is owned by the treebuilder that
+      // creates it. But since git_tree_entry is duplicable the generator will
+      // duplicate it and mark it as self freeing.
+      // Validate this with the leakTest.
+      return leakTest(Git.TreeEntry, function() {
+        return Git.Treebuilder.create(test.repo, null)
+        .then(function(builder) {
+          return builder.insert("test", oid, Git.TreeEntry.FILEMODE.BLOB);
+        });
+      });
+    });
 });