diff --git a/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/copilot-client.ts b/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/copilot-client.ts
index 1dcfc99b38..68e692ff9a 100644
--- a/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/copilot-client.ts
+++ b/packages/frontend/core/src/components/blocksuite/block-suite-editor/ai/copilot-client.ts
@@ -6,6 +6,7 @@ import {
   getBaseUrl,
   getCopilotHistoriesQuery,
   getCopilotSessionsQuery,
+  GraphQLError,
   type GraphQLQuery,
   type QueryOptions,
   type RequestOptions,
@@ -20,24 +21,53 @@ import { getCurrentStore } from '@toeverything/infra';
 type OptionsField<T extends GraphQLQuery> =
   RequestOptions<T>['variables'] extends { options: infer U } ? U : never;
 
+function codeToError(code: number) {
+  switch (code) {
+    case 401:
+      return new UnauthorizedError();
+    case 402:
+      return new PaymentRequiredError();
+    default:
+      return new GeneralNetworkError();
+  }
+}
+
+type ErrorType =
+  | GraphQLError[]
+  | GraphQLError
+  | { status: number }
+  | Error
+  | string;
+
+export function resolveError(src: ErrorType) {
+  if (typeof src === 'string') {
+    return new GeneralNetworkError(src);
+  } else if (src instanceof GraphQLError || Array.isArray(src)) {
+    // only resolve the first error
+    const error = Array.isArray(src) ? src.at(0) : src;
+    const code = error?.extensions?.code;
+    return codeToError(code ?? 500);
+  } else {
+    return codeToError(src instanceof Error ? 500 : src.status);
+  }
+}
+
+export function handleError(src: ErrorType) {
+  const err = resolveError(src);
+  if (err instanceof UnauthorizedError) {
+    getCurrentStore().set(showAILoginRequiredAtom, true);
+  }
+  return err;
+}
+
 const fetcher = async <Query extends GraphQLQuery>(
   options: QueryOptions<Query>
 ) => {
   try {
     return await defaultFetcher<Query>(options);
   } catch (_err) {
-    const error = Array.isArray(_err) ? _err.at(0) : _err;
-    const code = error.extensions?.code;
-
-    switch (code) {
-      case 401:
-        getCurrentStore().set(showAILoginRequiredAtom, true);
-        throw new UnauthorizedError();
-      case 402:
-        throw new PaymentRequiredError();
-      default:
-        throw new GeneralNetworkError();
-    }
+    const err = _err as GraphQLError | GraphQLError[] | Error | string;
+    throw handleError(err);
   }
 };
 
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
index 27e1b8511c..eec95bd0f0 100644
--- 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
@@ -1,4 +1,4 @@
-import { GeneralNetworkError } from '@blocksuite/blocks';
+import { handleError } from './copilot-client';
 
 export function delay(ms: number) {
   return new Promise(resolve => setTimeout(resolve, ms));
@@ -15,6 +15,17 @@ type toTextStreamOptions = {
   timeout?: number;
 };
 
+// todo: may need to extend the error type
+const safeParseError = (data: string): { status: number } => {
+  try {
+    return JSON.parse(data);
+  } catch {
+    return {
+      status: 500,
+    };
+  }
+};
+
 export function toTextStream(
   eventSource: EventSource,
   { timeout }: toTextStreamOptions = {}
@@ -52,7 +63,9 @@ export function toTextStream(
         // 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));
+          // try to parse the error message as a JSON object
+          const error = safeParseError(errorMessage);
+          rejectMessagePromise(handleError(error));
         } else {
           resolveMessagePromise();
         }