diff --git a/libs/langchain-aws/src/common.ts b/libs/langchain-aws/src/common.ts
index 13d5223241c0..14afc63cad6e 100644
--- a/libs/langchain-aws/src/common.ts
+++ b/libs/langchain-aws/src/common.ts
@@ -351,6 +351,7 @@ export function convertConverseMessageToLangChainMessage(
           id: c.toolUse.toolUseId,
           name: c.toolUse.name,
           args: c.toolUse.input,
+          type: "tool_call",
         });
       } else if ("text" in c && typeof c.text === "string") {
         content.push({ type: "text", text: c.text });
@@ -391,6 +392,7 @@ export function handleConverseStreamContentBlockDelta(
           {
             args: contentBlockDelta.delta.toolUse.input,
             index,
+            type: "tool_call_chunk",
           },
         ],
       }),
@@ -419,6 +421,7 @@ export function handleConverseStreamContentBlockStart(
             name: contentBlockStart.start.toolUse.name,
             id: contentBlockStart.start.toolUse.toolUseId,
             index,
+            type: "tool_call_chunk",
           },
         ],
       }),
diff --git a/libs/langchain-cohere/src/chat_models.ts b/libs/langchain-cohere/src/chat_models.ts
index ab49603f755a..eb6887e53dc6 100644
--- a/libs/langchain-cohere/src/chat_models.ts
+++ b/libs/langchain-cohere/src/chat_models.ts
@@ -599,6 +599,7 @@ export class ChatCohere<
       name: toolCall.function.name,
       args: toolCall.function.arguments,
       id: toolCall.id,
+      type: "tool_call",
     }));
   }
 
@@ -775,6 +776,7 @@ export class ChatCohere<
             args: toolCall.function.arguments,
             id: toolCall.id,
             index: toolCall.index,
+            type: "tool_call_chunk",
           }));
         }
 
diff --git a/libs/langchain-community/src/chat_models/bedrock/web.ts b/libs/langchain-community/src/chat_models/bedrock/web.ts
index a15dc949412a..3a2a350f97c9 100644
--- a/libs/langchain-community/src/chat_models/bedrock/web.ts
+++ b/libs/langchain-community/src/chat_models/bedrock/web.ts
@@ -33,7 +33,7 @@ import {
 } from "@langchain/core/outputs";
 import { StructuredToolInterface } from "@langchain/core/tools";
 import { isStructuredTool } from "@langchain/core/utils/function_calling";
-import { ToolCall } from "@langchain/core/messages/tool";
+import { ToolCall, ToolCallChunk } from "@langchain/core/messages/tool";
 import { zodToJsonSchema } from "zod-to-json-schema";
 
 import type { SerializedFields } from "../../load/map_keys.js";
@@ -562,14 +562,14 @@ export class BedrockChat
         options
       );
       const result = generations[0].message as AIMessage;
-      const toolCallChunks = result.tool_calls?.map(
-        (toolCall: ToolCall, index: number) => ({
+      const toolCallChunks: ToolCallChunk[] | undefined =
+        result.tool_calls?.map((toolCall: ToolCall, index: number) => ({
           name: toolCall.name,
           args: JSON.stringify(toolCall.args),
           id: toolCall.id,
           index,
-        })
-      );
+          type: "tool_call_chunk",
+        }));
       yield new ChatGenerationChunk({
         message: new AIMessageChunk({
           content: result.content,
diff --git a/libs/langchain-community/src/utils/bedrock/anthropic.ts b/libs/langchain-community/src/utils/bedrock/anthropic.ts
index 4bb888a9de77..6ed262795c08 100644
--- a/libs/langchain-community/src/utils/bedrock/anthropic.ts
+++ b/libs/langchain-community/src/utils/bedrock/anthropic.ts
@@ -14,7 +14,12 @@ export function extractToolCalls(content: Record<string, any>[]) {
   const toolCalls: ToolCall[] = [];
   for (const block of content) {
     if (block.type === "tool_use") {
-      toolCalls.push({ name: block.name, args: block.input, id: block.id });
+      toolCalls.push({
+        name: block.name,
+        args: block.input,
+        id: block.id,
+        type: "tool_call",
+      });
     }
   }
   return toolCalls;
diff --git a/libs/langchain-google-common/src/utils/gemini.ts b/libs/langchain-google-common/src/utils/gemini.ts
index 749b78ad27d9..432620dcc52b 100644
--- a/libs/langchain-google-common/src/utils/gemini.ts
+++ b/libs/langchain-google-common/src/utils/gemini.ts
@@ -21,6 +21,7 @@ import {
   ChatResult,
   Generation,
 } from "@langchain/core/outputs";
+import { ToolCallChunk } from "@langchain/core/messages/tool";
 import type {
   GoogleLLMResponse,
   GoogleAIModelParams,
@@ -597,13 +598,14 @@ export function responseToChatGenerations(
   if (ret.every((item) => typeof item.message.content === "string")) {
     const combinedContent = ret.map((item) => item.message.content).join("");
     const combinedText = ret.map((item) => item.text).join("");
-    const toolCallChunks = ret[
+    const toolCallChunks: ToolCallChunk[] | undefined = ret[
       ret.length - 1
     ]?.message.additional_kwargs?.tool_calls?.map((toolCall, i) => ({
       name: toolCall.function.name,
       args: toolCall.function.arguments,
       id: toolCall.id,
       index: i,
+      type: "tool_call_chunk",
     }));
     let usageMetadata: UsageMetadata | undefined;
     if ("usageMetadata" in response.data) {
@@ -653,6 +655,7 @@ export function partsToBaseMessageFields(parts: GeminiPart[]): AIMessageFields {
           name: tool.function.name,
           args: JSON.parse(tool.function.arguments),
           id: tool.id,
+          type: "tool_call",
         });
         // eslint-disable-next-line @typescript-eslint/no-explicit-any
       } catch (e: any) {
@@ -661,6 +664,7 @@ export function partsToBaseMessageFields(parts: GeminiPart[]): AIMessageFields {
           args: JSON.parse(tool.function.arguments),
           id: tool.id,
           error: e.message,
+          type: "invalid_tool_call",
         });
       }
     }
diff --git a/libs/langchain-google-genai/src/utils/common.ts b/libs/langchain-google-genai/src/utils/common.ts
index afb60eb69c8d..1d4bdddbaa66 100644
--- a/libs/langchain-google-genai/src/utils/common.ts
+++ b/libs/langchain-google-genai/src/utils/common.ts
@@ -264,7 +264,10 @@ export function mapGenerateContentResultToChatResult(
     text,
     message: new AIMessage({
       content: text,
-      tool_calls: functionCalls,
+      tool_calls: functionCalls?.map((fc) => ({
+        ...fc,
+        type: "tool_call",
+      })),
       additional_kwargs: {
         ...generationInfo,
       },
@@ -300,6 +303,7 @@ export function convertResponseContentToChatGenerationChunk(
         ...fc,
         args: JSON.stringify(fc.args),
         index: extra.index,
+        type: "tool_call_chunk" as const,
       }))
     );
   }
diff --git a/libs/langchain-groq/src/chat_models.ts b/libs/langchain-groq/src/chat_models.ts
index 1abe7b3db765..eb8f2dffc76d 100644
--- a/libs/langchain-groq/src/chat_models.ts
+++ b/libs/langchain-groq/src/chat_models.ts
@@ -64,6 +64,7 @@ import {
 } from "@langchain/core/output_parsers/openai_tools";
 import { StructuredToolInterface } from "@langchain/core/tools";
 import { convertToOpenAITool } from "@langchain/core/utils/function_calling";
+import { ToolCallChunk } from "@langchain/core/messages/tool";
 
 export interface ChatGroqCallOptions extends BaseChatModelCallOptions {
   headers?: Record<string, string>;
@@ -403,14 +404,14 @@ export class ChatGroq extends BaseChatModel<
       ) {
         throw new Error("Could not parse Groq output.");
       }
-      const toolCallChunks = generationMessage.tool_calls?.map(
-        (toolCall, i) => ({
+      const toolCallChunks: ToolCallChunk[] | undefined =
+        generationMessage.tool_calls?.map((toolCall, i) => ({
           name: toolCall.name,
           args: JSON.stringify(toolCall.args),
           id: toolCall.id,
           index: i,
-        })
-      );
+          type: "tool_call_chunk",
+        }));
       yield new ChatGenerationChunk({
         message: new AIMessageChunk({
           content: generationMessage.content,
diff --git a/libs/langchain-mistralai/src/chat_models.ts b/libs/langchain-mistralai/src/chat_models.ts
index ea0317f34d84..1a1fdd36e12b 100644
--- a/libs/langchain-mistralai/src/chat_models.ts
+++ b/libs/langchain-mistralai/src/chat_models.ts
@@ -65,6 +65,7 @@ import {
   RunnableToolLike,
 } from "@langchain/core/runnables";
 import { zodToJsonSchema } from "zod-to-json-schema";
+import { ToolCallChunk } from "@langchain/core/messages/tool";
 
 interface TokenUsage {
   completionTokens?: number;
@@ -321,7 +322,7 @@ function _convertDeltaToMessageChunk(
   }
   const content = delta.content ?? "";
   let additional_kwargs;
-  const toolCallChunks = [];
+  const toolCallChunks: ToolCallChunk[] = [];
   if (rawToolCallChunksWithIndex !== undefined) {
     additional_kwargs = {
       tool_calls: rawToolCallChunksWithIndex,
@@ -332,6 +333,7 @@ function _convertDeltaToMessageChunk(
         args: rawToolCallChunk.function?.arguments,
         id: rawToolCallChunk.id,
         index: rawToolCallChunk.index,
+        type: "tool_call_chunk",
       });
     }
   } else {
diff --git a/libs/langchain-openai/src/chat_models.ts b/libs/langchain-openai/src/chat_models.ts
index 601d70d33fff..c3f1f03ffc1b 100644
--- a/libs/langchain-openai/src/chat_models.ts
+++ b/libs/langchain-openai/src/chat_models.ts
@@ -55,6 +55,7 @@ import {
   parseToolCall,
 } from "@langchain/core/output_parsers/openai_tools";
 import { zodToJsonSchema } from "zod-to-json-schema";
+import { ToolCallChunk } from "@langchain/core/messages/tool";
 import type {
   AzureOpenAIInput,
   OpenAICallOptions,
@@ -184,7 +185,7 @@ function _convertDeltaToMessageChunk(
   if (role === "user") {
     return new HumanMessageChunk({ content });
   } else if (role === "assistant") {
-    const toolCallChunks = [];
+    const toolCallChunks: ToolCallChunk[] = [];
     if (Array.isArray(delta.tool_calls)) {
       for (const rawToolCall of delta.tool_calls) {
         toolCallChunks.push({
@@ -192,6 +193,7 @@ function _convertDeltaToMessageChunk(
           args: rawToolCall.function?.arguments,
           id: rawToolCall.id,
           index: rawToolCall.index,
+          type: "tool_call_chunk",
         });
       }
     }