diff --git a/packages/web/src/app/[domain]/askgh/[owner]/[repo]/components/landingPage.tsx b/packages/web/src/app/[domain]/askgh/[owner]/[repo]/components/landingPage.tsx
index 98d14eed6..9e29dd46c 100644
--- a/packages/web/src/app/[domain]/askgh/[owner]/[repo]/components/landingPage.tsx
+++ b/packages/web/src/app/[domain]/askgh/[owner]/[repo]/components/landingPage.tsx
@@ -5,11 +5,17 @@ import { SearchModeSelector } from "@/app/[domain]/components/searchModeSelector
 import { Separator } from "@/components/ui/separator";
 import { ChatBox } from "@/features/chat/components/chatBox";
 import { ChatBoxToolbar } from "@/features/chat/components/chatBox/chatBoxToolbar";
+import { LoginModal } from "./loginModal";
 import { NotConfiguredErrorBanner } from "@/features/chat/components/notConfiguredErrorBanner";
 import { LanguageModelInfo, RepoSearchScope } from "@/features/chat/types";
 import { useCreateNewChatThread } from "@/features/chat/useCreateNewChatThread";
 import { getRepoImageSrc } from '@/lib/utils';
-import { useMemo, useState } from "react";
+import type { IdentityProviderMetadata } from "@/lib/identityProviders";
+import { Descendant, Transforms } from "slate";
+import { useSlate } from "slate-react";
+import { useCallback, useEffect, useMemo, useState, useRef } from "react";
+
+const PENDING_MESSAGE_KEY = "askgh_pending_message";
 
 interface LandingPageProps {
     languageModels: LanguageModelInfo[];
@@ -17,6 +23,8 @@ interface LandingPageProps {
     repoDisplayName?: string;
     imageUrl?: string | null;
     repoId: number;
+    providers: IdentityProviderMetadata[];
+    isAuthenticated: boolean;
 }
 
 export const LandingPage = ({
@@ -25,9 +33,14 @@ export const LandingPage = ({
     repoDisplayName,
     imageUrl,
     repoId,
+    providers,
+    isAuthenticated,
 }: LandingPageProps) => {
+    const editor = useSlate();
     const { createNewChatThread, isLoading } = useCreateNewChatThread();
     const [isContextSelectorOpen, setIsContextSelectorOpen] = useState(false);
+    const [isLoginModalOpen, setIsLoginModalOpen] = useState(false);
+    const hasRestoredPendingMessage = useRef(false);
     const isChatBoxDisabled = languageModels.length === 0;
 
     const selectedSearchScopes = useMemo(() => [
@@ -39,6 +52,44 @@ export const LandingPage = ({
         } satisfies RepoSearchScope,
     ], [repoDisplayName, repoName]);
 
+    // Intercept submit to check auth status
+    const handleSubmit = useCallback((children: Descendant[]) => {
+        if (!isAuthenticated) {
+            // Store message in sessionStorage to survive OAuth redirect
+            sessionStorage.setItem(PENDING_MESSAGE_KEY, JSON.stringify(children));
+            setIsLoginModalOpen(true);
+            return;
+        }
+        createNewChatThread(children, selectedSearchScopes);
+    }, [isAuthenticated, createNewChatThread, selectedSearchScopes]);
+
+    // Restore pending message to editor and auto-submit after login
+    useEffect(() => {
+        if (isAuthenticated && !hasRestoredPendingMessage.current) {
+            const stored = sessionStorage.getItem(PENDING_MESSAGE_KEY);
+            if (stored) {
+                hasRestoredPendingMessage.current = true;
+                sessionStorage.removeItem(PENDING_MESSAGE_KEY);
+                try {
+                    const message = JSON.parse(stored) as Descendant[];
+
+                    // Restore the message content to the editor by replacing all nodes
+                    // Remove all existing nodes
+                    while (editor.children.length > 0) {
+                        Transforms.removeNodes(editor, { at: [0] });
+                    }
+                    // Insert the restored content at the beginning
+                    Transforms.insertNodes(editor, message, { at: [0] });
+
+                    // Allow the UI to render the restored text before auto-submitting
+                    createNewChatThread(message, selectedSearchScopes);
+                } catch (error) {
+                    console.error('Failed to restore pending message:', error);
+                }
+            }
+        }
+    }, [isAuthenticated, editor, createNewChatThread, selectedSearchScopes]);
+
     const imageSrc = imageUrl ? getRepoImageSrc(imageUrl, repoId) : undefined;
     const displayName = repoDisplayName ?? repoName;
 
@@ -66,9 +117,7 @@ export const LandingPage = ({
                 <div className="w-full max-w-[800px]">
                     <div className="border rounded-md w-full shadow-sm">
                         <ChatBox
-                            onSubmit={(children) => {
-                                createNewChatThread(children, selectedSearchScopes);
-                            }}
+                            onSubmit={handleSubmit}
                             className="min-h-[50px]"
                             isRedirecting={isLoading}
                             languageModels={languageModels}
@@ -85,7 +134,7 @@ export const LandingPage = ({
                                     repos={[]}
                                     searchContexts={[]}
                                     selectedSearchScopes={selectedSearchScopes}
-                                    onSelectedSearchScopesChange={() => {}}
+                                    onSelectedSearchScopesChange={() => { }}
                                     isContextSelectorOpen={isContextSelectorOpen}
                                     onContextSelectorOpenChanged={setIsContextSelectorOpen}
                                 />
@@ -102,6 +151,13 @@ export const LandingPage = ({
                     )}
                 </div>
             </div>
+
+            <LoginModal
+                isOpen={isLoginModalOpen}
+                onOpenChange={setIsLoginModalOpen}
+                providers={providers}
+                callbackUrl={typeof window !== 'undefined' ? window.location.href : ''}
+            />
         </div>
     )
 }
\ No newline at end of file
diff --git a/packages/web/src/app/[domain]/askgh/[owner]/[repo]/components/loginModal.tsx b/packages/web/src/app/[domain]/askgh/[owner]/[repo]/components/loginModal.tsx
new file mode 100644
index 000000000..d25223405
--- /dev/null
+++ b/packages/web/src/app/[domain]/askgh/[owner]/[repo]/components/loginModal.tsx
@@ -0,0 +1,46 @@
+'use client';
+
+import {
+    Dialog,
+    DialogContent,
+    DialogDescription,
+    DialogHeader,
+    DialogTitle,
+} from "@/components/ui/dialog";
+import { AuthMethodSelector } from "@/app/components/authMethodSelector";
+import type { IdentityProviderMetadata } from "@/lib/identityProviders";
+
+interface LoginModalProps {
+    isOpen: boolean;
+    onOpenChange: (open: boolean) => void;
+    providers: IdentityProviderMetadata[];
+    callbackUrl: string;
+}
+
+export const LoginModal = ({
+    isOpen,
+    onOpenChange,
+    providers,
+    callbackUrl,
+}: LoginModalProps) => {
+    return (
+        <Dialog open={isOpen} onOpenChange={onOpenChange}>
+            <DialogContent className="sm:max-w-md">
+                <DialogHeader>
+                    <DialogTitle className="mb-3">Sign up to continue</DialogTitle>
+                    <DialogDescription>
+                        Sign into your account to continue.
+                    </DialogDescription>
+                </DialogHeader>
+                <div className="mt-4">
+                    <AuthMethodSelector
+                        providers={providers}
+                        callbackUrl={callbackUrl}
+                        context="login"
+                        securityNoticeClosable={true}
+                    />
+                </div>
+            </DialogContent>
+        </Dialog>
+    );
+};
diff --git a/packages/web/src/app/[domain]/askgh/[owner]/[repo]/page.tsx b/packages/web/src/app/[domain]/askgh/[owner]/[repo]/page.tsx
index f5c4e98d8..ee1ad7d48 100644
--- a/packages/web/src/app/[domain]/askgh/[owner]/[repo]/page.tsx
+++ b/packages/web/src/app/[domain]/askgh/[owner]/[repo]/page.tsx
@@ -8,6 +8,8 @@ import { CustomSlateEditor } from "@/features/chat/customSlateEditor";
 import { RepoIndexedGuard } from "./components/repoIndexedGuard";
 import { LandingPage } from "./components/landingPage";
 import { getConfiguredLanguageModelsInfo } from "@/features/chat/actions";
+import { getIdentityProviderMetadata } from "@/lib/identityProviders";
+import { auth } from "@/auth";
 
 interface PageProps {
     params: Promise<{ owner: string; repo: string }>;
@@ -16,7 +18,8 @@ interface PageProps {
 export default async function GitHubRepoPage(props: PageProps) {
     const params = await props.params;
     const { owner, repo } = params;
-
+    const session = await auth();
+    
     const repoId = await (async () => {
         // 1. Look up repo by owner/repo
         const displayName = `${owner}/${repo}`;
@@ -45,6 +48,7 @@ export default async function GitHubRepoPage(props: PageProps) {
 
     const repoInfo = await unwrapServiceError(getRepoInfo(repoId));
     const languageModels = await unwrapServiceError(getConfiguredLanguageModelsInfo());
+    const providers = getIdentityProviderMetadata();
 
     return (
         <RepoIndexedGuard initialRepoInfo={repoInfo}>
@@ -55,6 +59,8 @@ export default async function GitHubRepoPage(props: PageProps) {
                     repoDisplayName={repoInfo.displayName ?? undefined}
                     imageUrl={repoInfo.imageUrl ?? undefined}
                     repoId={repoInfo.id}
+                    providers={providers}
+                    isAuthenticated={!!session?.user}
                 />
             </CustomSlateEditor>
         </RepoIndexedGuard>