diff --git a/package.json b/package.json
index b97cd5c..e3d6784 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@codota/token.js",
-  "version": "0.15.0",
+  "version": "0.16.0",
   "repository": {
     "type": "git",
     "url": "https://github.com/codota/token.js"
diff --git a/src/handlers/anthropic-vertex.ts b/src/handlers/anthropic-vertex.ts
index 1bb1134..f5c5221 100644
--- a/src/handlers/anthropic-vertex.ts
+++ b/src/handlers/anthropic-vertex.ts
@@ -178,7 +178,16 @@ export async function* createCompletionResponseStreaming(
       index: 0,
       finish_reason: finishReason,
       logprobs: null,
-      delta,
+      delta: finishReason === "tool_calls" ? {
+        tool_calls: [
+          {
+            index: 0,
+            function: {
+              arguments: '{}',
+            },
+          },
+        ],
+      } : delta,
     }
 
     yield {