fix anthropic streaming tool index increment

Co-authored-by: lucgagan <[email protected]>

Author: narengogi

src/providers/anthropic/chatComplete.ts

@@ -606,6 +606,9 @@ export const AnthropicChatCompleteStreamChunkTransform: (
   streamState,
   strictOpenAiCompliance
 ) => {
+  if (streamState.toolIndex == undefined) {
+    streamState.toolIndex = -1;
+  }
   let chunk = responseChunk.trim();
   if (
     chunk.startsWith('event: ping') ||
@@ -724,9 +727,7 @@ export const AnthropicChatCompleteStreamChunkTransform: (
     parsedChunk.type === 'content_block_start' &&
     parsedChunk.content_block?.type === 'tool_use';
   if (isToolBlockStart) {
-    streamState.toolIndex = streamState.toolIndex
-      ? streamState.toolIndex + 1
-      : 0;
+    streamState.toolIndex = streamState.toolIndex + 1;
   }
   const isToolBlockDelta: boolean =
     parsedChunk.type === 'content_block_delta' &&

src/providers/google-vertex-ai/chatComplete.ts

@@ -786,6 +786,9 @@ export const VertexAnthropicChatCompleteStreamChunkTransform: (
   streamState,
   strictOpenAiCompliance
 ) => {
+  if (streamState.toolIndex == undefined) {
+    streamState.toolIndex = -1;
+  }
   let chunk = responseChunk.trim();
 
   if (
@@ -893,9 +896,7 @@ export const VertexAnthropicChatCompleteStreamChunkTransform: (
     parsedChunk.type === 'content_block_start' &&
     parsedChunk.content_block?.type === 'tool_use';
   if (isToolBlockStart) {
-    streamState.toolIndex = streamState.toolIndex
-      ? streamState.toolIndex + 1
-      : 0;
+    streamState.toolIndex = streamState.toolIndex + 1;
   }
   const isToolBlockDelta: boolean =
     parsedChunk.type === 'content_block_delta' &&