diff --git a/langchain-core/src/tools/base.ts b/langchain-core/src/tools/base.ts
index c981b174387c..21258f03baf6 100644
--- a/langchain-core/src/tools/base.ts
+++ b/langchain-core/src/tools/base.ts
@@ -13,9 +13,13 @@ import { ensureConfig, type RunnableConfig } from "../runnables/config.js";
 import type { RunnableFunc, RunnableInterface } from "../runnables/base.js";
 import { ToolCall, ToolMessage } from "../messages/tool.js";
 import { ZodAny } from "../types/zod.js";
+import { MessageContent } from "../messages/base.js";
 
 export type ResponseFormat = "content" | "contentAndRawOutput";
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type ContentAndRawOutput = [MessageContent, any];
+
 /**
  * Parameters for the Tool classes.
  */
@@ -119,7 +123,7 @@ export abstract class StructuredTool<
     arg: z.output<T>,
     runManager?: CallbackManagerForToolRun,
     config?: RunnableConfig
-  ): Promise<RunOutput>;
+  ): Promise<string | ContentAndRawOutput>;
 
   /**
    * Invokes the tool with the provided input and configuration.
@@ -294,22 +298,19 @@ export interface BaseDynamicToolInput extends ToolParams {
 /**
  * Interface for the input parameters of the DynamicTool class.
  */
-export interface DynamicToolInput<
-  RunOutput extends string | ToolMessage = string
-> extends BaseDynamicToolInput {
+export interface DynamicToolInput extends BaseDynamicToolInput {
   func: (
     input: string,
     runManager?: CallbackManagerForToolRun,
     config?: RunnableConfig
-  ) => Promise<RunOutput>;
+  ) => Promise<string | ContentAndRawOutput>;
 }
 
 /**
  * Interface for the input parameters of the DynamicStructuredTool class.
  */
 export interface DynamicStructuredToolInput<
-  T extends ZodAny = ZodAny,
-  RunOutput extends string | ToolMessage = string
+  T extends ZodAny = ZodAny
 > extends BaseDynamicToolInput {
   func: (
     input: BaseDynamicToolInput["responseFormat"] extends "contentAndRawOutput"
@@ -317,7 +318,7 @@ export interface DynamicStructuredToolInput<
       : z.infer<T>,
     runManager?: CallbackManagerForToolRun,
     config?: RunnableConfig
-  ) => Promise<RunOutput>;
+  ) => Promise<string | ContentAndRawOutput>;
   schema: T;
 }
 
@@ -335,9 +336,9 @@ export class DynamicTool<
 
   description: string;
 
-  func: DynamicToolInput<RunOutput>["func"];
+  func: DynamicToolInput["func"];
 
-  constructor(fields: DynamicToolInput<RunOutput>) {
+  constructor(fields: DynamicToolInput) {
     super(fields);
     this.name = fields.name;
     this.description = fields.description;
@@ -364,7 +365,7 @@ export class DynamicTool<
     input: string,
     runManager?: CallbackManagerForToolRun,
     config?: RunnableConfig
-  ): Promise<RunOutput> {
+  ): Promise<string | ContentAndRawOutput> {
     return this.func(input, runManager, config);
   }
 }
@@ -387,11 +388,11 @@ export class DynamicStructuredTool<
 
   description: string;
 
-  func: DynamicStructuredToolInput<T, RunOutput>["func"];
+  func: DynamicStructuredToolInput<T>["func"];
 
   schema: T;
 
-  constructor(fields: DynamicStructuredToolInput<T, RunOutput>) {
+  constructor(fields: DynamicStructuredToolInput<T>) {
     super(fields);
     this.name = fields.name;
     this.description = fields.description;
@@ -420,7 +421,7 @@ export class DynamicStructuredTool<
     arg: z.output<T> | ToolCall,
     runManager?: CallbackManagerForToolRun,
     config?: RunnableConfig
-  ): Promise<RunOutput> {
+  ): Promise<string | ContentAndRawOutput> {
     return this.func(arg, runManager, config);
   }
 }
@@ -491,9 +492,9 @@ interface ToolWrapperParams<RunInput extends ZodAny = ZodAny>
 export function tool<
   RunInput extends ZodAny = ZodAny,
   RunOutput extends ToolMessage = ToolMessage,
-  FuncInput extends z.infer<RunInput> | ToolCall = z.infer<RunInput>
+  FuncInput extends z.infer<RunInput> | ToolCall = z.infer<RunInput>,
 >(
-  func: RunnableFunc<FuncInput, RunOutput>,
+  func: RunnableFunc<FuncInput, ContentAndRawOutput>,
   fields: Omit<ToolWrapperParams<RunInput>, "responseFormat"> & {
     responseFormat: "contentAndRawOutput";
   }
@@ -502,9 +503,9 @@ export function tool<
 export function tool<
   RunInput extends ZodAny = ZodAny,
   RunOutput extends string = string,
-  FuncInput extends z.infer<RunInput> | ToolCall = z.infer<RunInput>
+  FuncInput extends z.infer<RunInput> | ToolCall = z.infer<RunInput>,
 >(
-  func: RunnableFunc<FuncInput, RunOutput>,
+  func: RunnableFunc<FuncInput, string>,
   fields: Omit<ToolWrapperParams<RunInput>, "responseFormat"> & {
     responseFormat?: "content" | undefined;
   }
@@ -513,9 +514,10 @@ export function tool<
 export function tool<
   RunInput extends ZodAny = ZodAny,
   RunOutput extends string | ToolMessage = string,
-  FuncInput extends z.infer<RunInput> | ToolCall = z.infer<RunInput>
+  FuncInput extends z.infer<RunInput> | ToolCall = z.infer<RunInput>,
+  FuncOutput extends string | ContentAndRawOutput = string,
 >(
-  func: RunnableFunc<FuncInput, RunOutput>,
+  func: RunnableFunc<FuncInput, FuncOutput>,
   fields: ToolWrapperParams<RunInput>
 ): DynamicStructuredTool<RunInput, RunOutput> {
   const schema =
diff --git a/langchain-core/src/tools/tests/tools.test.ts b/langchain-core/src/tools/tests/tools.test.ts
index 6e906aa75b90..c513ffb363c8 100644
--- a/langchain-core/src/tools/tests/tools.test.ts
+++ b/langchain-core/src/tools/tests/tools.test.ts
@@ -1,13 +1,14 @@
+import { test, expect } from "@jest/globals";
 import { z } from "zod";
-import { tool } from "../base.js";
+import { ContentAndRawOutput, tool } from "../base.js";
 import { ToolCall, ToolMessage } from "../../messages/tool.js";
 
-test("Tool should throw type error if responseFormat does not match func input type", () => {
+test("Tool should throw type error if types are wrong", () => {
   const weatherSchema = z.object({
     location: z.string(),
   });
 
-  // @ts-expect-error - Error because responseFormat: contentAndRawOutput makes return type be an instance of ToolMessage
+  // @ts-expect-error - Error because responseFormat: contentAndRawOutput makes return type ContentAndRawOutput
   tool(
     (_): string => {
       return "no-op";
@@ -21,11 +22,8 @@ test("Tool should throw type error if responseFormat does not match func input t
 
   // @ts-expect-error - Error because responseFormat: content makes return type be a string
   tool(
-    (_): ToolMessage => {
-      return new ToolMessage({
-        content: "no-op",
-        tool_call_id: "no-op",
-      });
+    (_): ContentAndRawOutput => {
+      return ["no-op", true]
     },
     {
       name: "weather",
@@ -36,11 +34,8 @@ test("Tool should throw type error if responseFormat does not match func input t
 
   // @ts-expect-error - Error because responseFormat: undefined makes return type be a string
   tool(
-    (_): ToolMessage => {
-      return new ToolMessage({
-        content: "no-op",
-        tool_call_id: "no-op",
-      });
+    (_): ContentAndRawOutput => {
+      return ["no-op", true]
     },
     {
       name: "weather",
@@ -50,11 +45,8 @@ test("Tool should throw type error if responseFormat does not match func input t
 
   // Should pass because we're expecting a `ToolMessage` return type due to `responseFormat: contentAndRawOutput`
   tool(
-    (_): ToolMessage => {
-      return new ToolMessage({
-        content: "no-op",
-        tool_call_id: "no-op",
-      });
+    (_): ContentAndRawOutput => {
+      return ["no-op", true]
     },
     {
       name: "weather",
@@ -108,3 +100,47 @@ test("Tool should throw type error if responseFormat does not match func input t
     }
   );
 });
+
+test("Tool should error if responseFormat is contentAndRawOutput but the function doesn't return a tuple", async () => {
+  const weatherSchema = z.object({
+    location: z.string(),
+  });
+
+  const weatherTool = tool(
+    (_): any => {
+      return "str"
+    },
+    {
+      name: "weather",
+      schema: weatherSchema,
+      responseFormat: "contentAndRawOutput",
+    }
+  );
+
+  await expect(async () => {
+    await weatherTool.invoke({ location: "San Francisco" });
+  }).rejects.toThrow();
+});
+
+test.only("Tool works if responseFormat is contentAndRawOutput and returns a tuple", async () => {
+  const weatherSchema = z.object({
+    location: z.string(),
+  });
+
+  const weatherTool = tool(
+    (input): any => {
+      return ["msg_content", input]
+    },
+    {
+      name: "weather",
+      schema: weatherSchema,
+      responseFormat: "contentAndRawOutput",
+    }
+  );
+
+  const toolResult = await weatherTool.invoke({ location: "San Francisco" });
+  
+  expect(toolResult).toBeInstanceOf(ToolMessage);
+  expect(toolResult.content).toBe("msg_content");
+  expect(toolResult.raw_output).toEqual({ location: "San Francisco" });
+});
\ No newline at end of file