diff --git a/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/event-source.ts b/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/event-source.ts
new file mode 100644
index 0000000000..27e1b8511c
--- /dev/null
+++ b/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/event-source.ts
@@ -0,0 +1,86 @@
+import { GeneralNetworkError } from '@blocksuite/blocks';
+
+export function delay(ms: number) {
+  return new Promise(resolve => setTimeout(resolve, ms));
+}
+
+export type AffineTextEvent = {
+  type: 'attachment' | 'message';
+  data: string;
+};
+
+type AffineTextStream = AsyncIterable<AffineTextEvent>;
+
+type toTextStreamOptions = {
+  timeout?: number;
+};
+
+export function toTextStream(
+  eventSource: EventSource,
+  { timeout }: toTextStreamOptions = {}
+): AffineTextStream {
+  return {
+    [Symbol.asyncIterator]: async function* () {
+      const messageQueue: AffineTextEvent[] = [];
+      let resolveMessagePromise: () => void;
+      let rejectMessagePromise: (err: Error) => void;
+
+      function resetMessagePromise() {
+        if (resolveMessagePromise) {
+          resolveMessagePromise();
+        }
+        return new Promise<void>((resolve, reject) => {
+          resolveMessagePromise = resolve;
+          rejectMessagePromise = reject;
+        });
+      }
+      let messagePromise = resetMessagePromise();
+
+      function messageListener(event: MessageEvent) {
+        messageQueue.push({
+          type: event.type as 'attachment' | 'message',
+          data: event.data as string,
+        });
+        messagePromise = resetMessagePromise();
+      }
+
+      eventSource.addEventListener('message', messageListener);
+      eventSource.addEventListener('attachment', messageListener);
+
+      eventSource.addEventListener('error', event => {
+        const errorMessage = (event as unknown as { data: string }).data;
+        // if there is data in Error event, it means the server sent an error message
+        // otherwise, the stream is finished successfully
+        if (event.type === 'error' && errorMessage) {
+          rejectMessagePromise(new GeneralNetworkError(errorMessage));
+        } else {
+          resolveMessagePromise();
+        }
+        eventSource.close();
+      });
+
+      try {
+        while (eventSource.readyState !== EventSource.CLOSED) {
+          if (messageQueue.length === 0) {
+            // Wait for the next message or timeout
+            await (timeout
+              ? Promise.race([
+                  messagePromise,
+                  delay(timeout).then(() => {
+                    throw new Error('Timeout');
+                  }),
+                ])
+              : messagePromise);
+          } else if (messageQueue.length > 0) {
+            const top = messageQueue.shift();
+            if (top) {
+              yield top;
+            }
+          }
+        }
+      } finally {
+        eventSource.close();
+      }
+    },
+  };
+}
diff --git a/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/request.ts b/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/request.ts
index af41b8b9b3..fa50d6f29d 100644
--- a/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/request.ts
+++ b/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/request.ts
@@ -1,7 +1,7 @@
-import { toTextStream } from '@blocksuite/presets';
 import { partition } from 'lodash-es';
 
 import { CopilotClient } from './copilot-client';
+import { delay, toTextStream } from './event-source';
 import type { PromptKey } from './prompt';
 
 const TIMEOUT = 50000;
@@ -116,21 +116,22 @@ export function textToText({
           params,
           sessionId,
         });
-
         const eventSource = client.chatTextStream({
           sessionId: message.sessionId,
           messageId: message.messageId,
         });
-        yield* toTextStream(eventSource, { timeout });
+        for await (const event of toTextStream(eventSource, { timeout })) {
+          if (event.type === 'message') {
+            yield event.data;
+          }
+        }
       },
     };
   } else {
     return Promise.race([
       timeout
-        ? new Promise((_res, rej) => {
-            setTimeout(() => {
-              rej(new Error('Timeout'));
-            }, timeout);
+        ? delay(timeout).then(() => {
+            throw new Error('Timeout');
           })
         : null,
       createSessionMessage({
@@ -141,8 +142,8 @@ export function textToText({
         attachments,
         params,
         sessionId,
-      }).then(async message => {
-        return await client.chatText({
+      }).then(message => {
+        return client.chatText({
           sessionId: message.sessionId,
           messageId: message.messageId,
         });
@@ -175,7 +176,11 @@ export function toImage({
       });
 
       const eventSource = client.imagesStream(messageId, sessionId);
-      yield* toTextStream(eventSource, { timeout, type: 'attachment' });
+      for await (const event of toTextStream(eventSource, { timeout })) {
+        if (event.type === 'attachment') {
+          yield event.data;
+        }
+      }
     },
   };
 }