diff --git a/packages/core/src/code_assist/server.test.ts b/packages/core/src/code_assist/server.test.ts
index 89ce45e1aa..8ec8cb8dad 100644
--- a/packages/core/src/code_assist/server.test.ts
+++ b/packages/core/src/code_assist/server.test.ts
@@ -408,6 +408,48 @@ describe('CodeAssistServer', () => {
     expect(results[1].candidates?.[0].content?.parts?.[0].text).toBe(' World');
   });
 
+  it('should handle Web ReadableStream in generateContentStream', async () => {
+    const { server, mockRequest } = createTestServer();
+
+    // Create a mock Web ReadableStream
+    const mockWebStream = new ReadableStream({
+      start(controller) {
+        const mockResponseData = {
+          response: {
+            candidates: [{ content: { parts: [{ text: 'Hello Web' }] } }],
+          },
+        };
+        controller.enqueue(
+          new TextEncoder().encode(
+            'data: ' + JSON.stringify(mockResponseData) + '\n\n',
+          ),
+        );
+        controller.close();
+      },
+    });
+
+    mockRequest.mockResolvedValue({ data: mockWebStream });
+
+    const stream = await server.generateContentStream(
+      {
+        model: 'test-model',
+        contents: [{ role: 'user', parts: [{ text: 'request' }] }],
+      },
+      'user-prompt-id',
+      LlmRole.MAIN,
+    );
+
+    const results = [];
+    for await (const res of stream) {
+      results.push(res);
+    }
+
+    expect(results).toHaveLength(1);
+    expect(results[0].candidates?.[0].content?.parts?.[0].text).toBe(
+      'Hello Web',
+    );
+  });
+
   it('should ignore malformed SSE data', async () => {
     const { server, mockRequest } = createTestServer();
 
diff --git a/packages/core/src/code_assist/server.ts b/packages/core/src/code_assist/server.ts
index 871af4cbfa..ba9b96bcb3 100644
--- a/packages/core/src/code_assist/server.ts
+++ b/packages/core/src/code_assist/server.ts
@@ -36,6 +36,7 @@ import type {
   GenerateContentResponse,
 } from '@google/genai';
 import * as readline from 'node:readline';
+import { Readable } from 'node:stream';
 import type { ContentGenerator } from '../core/contentGenerator.js';
 import { UserTierId } from './types.js';
 import type {
@@ -341,7 +342,7 @@ export class CodeAssistServer implements ContentGenerator {
     req: object,
     signal?: AbortSignal,
   ): Promise<AsyncGenerator<T>> {
-    const res = await this.client.request({
+    const res = await this.client.request<AsyncIterable<unknown>>({
       url: this.getMethodUrl(method),
       method: 'POST',
       params: {
@@ -358,8 +359,7 @@ export class CodeAssistServer implements ContentGenerator {
 
     return (async function* (): AsyncGenerator<T> {
       const rl = readline.createInterface({
-        // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
-        input: res.data as NodeJS.ReadableStream,
+        input: Readable.from(res.data),
         crlfDelay: Infinity, // Recognizes '\r\n' and '\n' as line breaks
       });