diff --git a/src/app/api/[[...route]]/route.ts b/src/app/api/[[...route]]/route.ts
index 12ae66e..2485c85 100644
--- a/src/app/api/[[...route]]/route.ts
+++ b/src/app/api/[[...route]]/route.ts
@@ -11,9 +11,9 @@ import { EventBus } from "../../../server/service/events/EventBus";
 import { FileWatcherService } from "../../../server/service/events/fileWatcher";
 import { ProjectMetaService } from "../../../server/service/project/ProjectMetaService";
 import { ProjectRepository } from "../../../server/service/project/ProjectRepository";
-import { VirtualConversationDatabase } from "../../../server/service/session/PredictSessionsDatabase";
 import { SessionMetaService } from "../../../server/service/session/SessionMetaService";
 import { SessionRepository } from "../../../server/service/session/SessionRepository";
+import { VirtualConversationDatabase } from "../../../server/service/session/VirtualConversationDatabase";
 
 const program = routes(honoApp);
 
diff --git a/src/app/components/MarkdownContent.tsx b/src/app/components/MarkdownContent.tsx
index e5acb61..9b7d2d9 100644
--- a/src/app/components/MarkdownContent.tsx
+++ b/src/app/components/MarkdownContent.tsx
@@ -1,9 +1,13 @@
 "use client";
 
+import { useTheme } from "next-themes";
 import type { FC } from "react";
 import Markdown from "react-markdown";
 import { Prism as SyntaxHighlighter } from "react-syntax-highlighter";
-import { oneDark } from "react-syntax-highlighter/dist/esm/styles/prism";
+import {
+  oneDark,
+  oneLight,
+} from "react-syntax-highlighter/dist/esm/styles/prism";
 import remarkGfm from "remark-gfm";
 
 interface MarkdownContentProps {
@@ -15,6 +19,9 @@ export const MarkdownContent: FC<MarkdownContentProps> = ({
   content,
   className = "",
 }) => {
+  const { resolvedTheme } = useTheme();
+  const syntaxTheme = resolvedTheme === "dark" ? oneDark : oneLight;
+
   return (
     <div
       className={`prose prose-neutral dark:prose-invert max-w-none ${className}`}
@@ -136,7 +143,7 @@ export const MarkdownContent: FC<MarkdownContentProps> = ({
                   </span>
                 </div>
                 <SyntaxHighlighter
-                  style={oneDark}
+                  style={syntaxTheme}
                   language={match[1]}
                   PreTag="div"
                   className="!mt-0 !rounded-t-none !rounded-b-lg !border-t-0 !border !border-border"
diff --git a/src/app/components/RootErrorBoundary.tsx b/src/app/components/RootErrorBoundary.tsx
index fe68a7a..f18c9ac 100644
--- a/src/app/components/RootErrorBoundary.tsx
+++ b/src/app/components/RootErrorBoundary.tsx
@@ -1,15 +1,62 @@
 "use client";
 
+import { AlertCircle, Home, RefreshCw } from "lucide-react";
 import type { FC, PropsWithChildren } from "react";
 import { ErrorBoundary } from "react-error-boundary";
 
+import { Alert, AlertDescription, AlertTitle } from "@/components/ui/alert";
+import { Button } from "@/components/ui/button";
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from "@/components/ui/card";
+
 export const RootErrorBoundary: FC<PropsWithChildren> = ({ children }) => {
   return (
     <ErrorBoundary
-      FallbackComponent={({ error }) => (
-        <div>
-          <h1>Error</h1>
-          <p>{error.message}</p>
+      FallbackComponent={({ error, resetErrorBoundary }) => (
+        <div className="flex min-h-screen items-center justify-center p-4">
+          <Card className="w-full max-w-2xl">
+            <CardHeader>
+              <div className="flex items-center gap-3">
+                <AlertCircle className="size-6 text-destructive" />
+                <div>
+                  <CardTitle>Something went wrong</CardTitle>
+                  <CardDescription>
+                    An unexpected error occurred in the application
+                  </CardDescription>
+                </div>
+              </div>
+            </CardHeader>
+            <CardContent className="space-y-4">
+              <Alert variant="destructive">
+                <AlertCircle />
+                <AlertTitle>Error Details</AlertTitle>
+                <AlertDescription>
+                  <code className="text-xs">{error.message}</code>
+                </AlertDescription>
+              </Alert>
+
+              <div className="flex gap-2">
+                <Button onClick={resetErrorBoundary} variant="default">
+                  <RefreshCw />
+                  Try Again
+                </Button>
+                <Button
+                  onClick={() => {
+                    window.location.href = "/";
+                  }}
+                  variant="outline"
+                >
+                  <Home />
+                  Go to Home
+                </Button>
+              </div>
+            </CardContent>
+          </Card>
         </div>
       )}
     >
diff --git a/src/app/components/SSEEventListeners.tsx b/src/app/components/SSEEventListeners.tsx
index 50bf595..0d0b0c3 100644
--- a/src/app/components/SSEEventListeners.tsx
+++ b/src/app/components/SSEEventListeners.tsx
@@ -12,14 +12,12 @@ export const SSEEventListeners: FC<PropsWithChildren> = ({ children }) => {
   const setSessionProcesses = useSetAtom(sessionProcessesAtom);
 
   useServerEventListener("sessionListChanged", async (event) => {
-    // invalidate session list
     await queryClient.invalidateQueries({
       queryKey: projectDetailQuery(event.projectId).queryKey,
     });
   });
 
   useServerEventListener("sessionChanged", async (event) => {
-    // invalidate session detail
     await queryClient.invalidateQueries({
       queryKey: sessionDetailQuery(event.projectId, event.sessionId).queryKey,
     });
diff --git a/src/app/error.tsx b/src/app/error.tsx
new file mode 100644
index 0000000..b52733a
--- /dev/null
+++ b/src/app/error.tsx
@@ -0,0 +1,69 @@
+"use client";
+
+import { AlertCircle, Home, RefreshCw } from "lucide-react";
+
+import { Alert, AlertDescription, AlertTitle } from "@/components/ui/alert";
+import { Button } from "@/components/ui/button";
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from "@/components/ui/card";
+
+export default function ErrorPage({
+  error,
+  reset,
+}: {
+  error: Error & { digest?: string };
+  reset: () => void;
+}) {
+  return (
+    <div className="flex min-h-screen items-center justify-center p-4">
+      <Card className="w-full max-w-2xl">
+        <CardHeader>
+          <div className="flex items-center gap-3">
+            <AlertCircle className="size-6 text-destructive" />
+            <div>
+              <CardTitle>Something went wrong</CardTitle>
+              <CardDescription>
+                An unexpected error occurred in the application
+              </CardDescription>
+            </div>
+          </div>
+        </CardHeader>
+        <CardContent className="space-y-4">
+          <Alert variant="destructive">
+            <AlertCircle />
+            <AlertTitle>Error Details</AlertTitle>
+            <AlertDescription>
+              <code className="text-xs">{error.message}</code>
+              {error.digest && (
+                <div className="mt-2 text-xs text-muted-foreground">
+                  Error ID: {error.digest}
+                </div>
+              )}
+            </AlertDescription>
+          </Alert>
+
+          <div className="flex gap-2">
+            <Button onClick={reset} variant="default">
+              <RefreshCw />
+              Try Again
+            </Button>
+            <Button
+              onClick={() => {
+                window.location.href = "/";
+              }}
+              variant="outline"
+            >
+              <Home />
+              Go to Home
+            </Button>
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  );
+}
diff --git a/src/app/layout.tsx b/src/app/layout.tsx
index f882369..66e7d12 100644
--- a/src/app/layout.tsx
+++ b/src/app/layout.tsx
@@ -1,5 +1,6 @@
 import { QueryClient } from "@tanstack/react-query";
 import { Geist, Geist_Mono } from "next/font/google";
+import { ThemeProvider } from "next-themes";
 
 import { Toaster } from "../components/ui/sonner";
 import { QueryClientProviderWrapper } from "../lib/api/QueryClientProviderWrapper";
@@ -47,24 +48,26 @@ export default async function RootLayout({
     .then((response) => response.json());
 
   return (
-    <html lang="en">
+    <html lang="en" suppressHydrationWarning>
       <body
         className={`${geistSans.variable} ${geistMono.variable} antialiased`}
       >
-        <RootErrorBoundary>
-          <QueryClientProviderWrapper>
-            <SSEProvider>
-              <SSEEventListeners>
-                <SyncSessionProcess
-                  initProcesses={initSessionProcesses.processes}
-                >
-                  {children}
-                </SyncSessionProcess>
-              </SSEEventListeners>
-            </SSEProvider>
-          </QueryClientProviderWrapper>
-        </RootErrorBoundary>
-        <Toaster position="top-right" />
+        <ThemeProvider attribute="class" defaultTheme="system" enableSystem>
+          <RootErrorBoundary>
+            <QueryClientProviderWrapper>
+              <SSEProvider>
+                <SSEEventListeners>
+                  <SyncSessionProcess
+                    initProcesses={initSessionProcesses.processes}
+                  >
+                    {children}
+                  </SyncSessionProcess>
+                </SSEEventListeners>
+              </SSEProvider>
+            </QueryClientProviderWrapper>
+          </RootErrorBoundary>
+          <Toaster position="top-right" />
+        </ThemeProvider>
       </body>
     </html>
   );
diff --git a/src/app/not-found.tsx b/src/app/not-found.tsx
new file mode 100644
index 0000000..79097e7
--- /dev/null
+++ b/src/app/not-found.tsx
@@ -0,0 +1,41 @@
+import { FileQuestion, Home } from "lucide-react";
+import Link from "next/link";
+
+import { Button } from "@/components/ui/button";
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from "@/components/ui/card";
+
+export default function NotFoundPage() {
+  return (
+    <div className="flex min-h-screen items-center justify-center p-4">
+      <Card className="w-full max-w-2xl">
+        <CardHeader>
+          <div className="flex items-center gap-3">
+            <FileQuestion className="size-6 text-muted-foreground" />
+            <div>
+              <CardTitle>Page Not Found</CardTitle>
+              <CardDescription>
+                The page you are looking for does not exist
+              </CardDescription>
+            </div>
+          </div>
+        </CardHeader>
+        <CardContent>
+          <div className="flex gap-2">
+            <Button asChild variant="default">
+              <Link href="/">
+                <Home />
+                Go to Home
+              </Link>
+            </Button>
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  );
+}
diff --git a/src/app/projects/[projectId]/components/ProjectPage.tsx b/src/app/projects/[projectId]/components/ProjectPage.tsx
deleted file mode 100644
index 0d4077d..0000000
--- a/src/app/projects/[projectId]/components/ProjectPage.tsx
+++ /dev/null
@@ -1,221 +0,0 @@
-"use client";
-
-import { useQueryClient } from "@tanstack/react-query";
-import {
-  ArrowLeftIcon,
-  ChevronDownIcon,
-  FolderIcon,
-  MessageSquareIcon,
-  PlusIcon,
-  SettingsIcon,
-} from "lucide-react";
-import Link from "next/link";
-import { useEffect, useState } from "react";
-import { SettingsControls } from "@/components/SettingsControls";
-import { Button } from "@/components/ui/button";
-import {
-  Card,
-  CardContent,
-  CardDescription,
-  CardHeader,
-  CardTitle,
-} from "@/components/ui/card";
-import {
-  Collapsible,
-  CollapsibleContent,
-  CollapsibleTrigger,
-} from "@/components/ui/collapsible";
-import { useConfig } from "../../../hooks/useConfig";
-import { useProject } from "../hooks/useProject";
-import { firstCommandToTitle } from "../services/firstCommandToTitle";
-import { NewChatModal } from "./newChat/NewChatModal";
-
-export const ProjectPageContent = ({ projectId }: { projectId: string }) => {
-  const { data, fetchNextPage, hasNextPage, isFetchingNextPage } =
-    useProject(projectId);
-  const { config } = useConfig();
-  const queryClient = useQueryClient();
-  const [isSettingsOpen, setIsSettingsOpen] = useState(false);
-
-  // Flatten all pages to get project and sessions
-  const project = data.pages.at(0)?.project;
-  const sessions = data.pages.flatMap((page) => page.sessions);
-
-  if (!project) {
-    throw new Error("Unreachable: Project must be defined.");
-  }
-
-  // biome-ignore lint/correctness/useExhaustiveDependencies: invalidate when config changed
-  useEffect(() => {
-    void queryClient.refetchQueries({
-      queryKey: ["projects", projectId],
-    });
-  }, [config.hideNoUserMessageSession, config.unifySameTitleSession]);
-
-  return (
-    <div className="container mx-auto px-2 sm:px-4 py-4 sm:py-8 max-w-6xl">
-      <header className="mb-6 sm:mb-8">
-        <Button asChild variant="ghost" className="mb-4">
-          <Link href="/projects" className="flex items-center gap-2">
-            <ArrowLeftIcon className="w-4 h-4" />
-            <span className="hidden sm:inline">Back to Projects</span>
-            <span className="sm:hidden">Back</span>
-          </Link>
-        </Button>
-
-        <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between mb-2">
-          <div className="flex items-center gap-2 sm:gap-3 min-w-0 flex-1">
-            <FolderIcon className="w-5 h-5 sm:w-6 sm:h-6 flex-shrink-0" />
-            <h1 className="text-xl sm:text-2xl md:text-3xl font-bold break-words overflow-hidden">
-              {project.meta.projectPath ?? project.claudeProjectPath}
-            </h1>
-          </div>
-          <div className="flex-shrink-0">
-            <NewChatModal
-              projectId={projectId}
-              trigger={
-                <Button
-                  size="lg"
-                  className="gap-2 w-full sm:w-auto"
-                  data-testid="new-chat"
-                >
-                  <PlusIcon className="w-4 h-4 sm:w-5 sm:h-5" />
-                  <span className="hidden sm:inline">Start New Chat</span>
-                  <span className="sm:hidden">New Chat</span>
-                </Button>
-              }
-            />
-          </div>
-        </div>
-        <p className="text-muted-foreground font-mono text-xs sm:text-sm break-all">
-          History File: {project.claudeProjectPath ?? "unknown"}
-        </p>
-      </header>
-
-      <main>
-        <section>
-          <h2 className="text-lg sm:text-xl font-semibold mb-4">
-            Conversation Sessions{" "}
-            {sessions.length > 0 ? `(${sessions.length})` : ""}
-          </h2>
-
-          {/* Filter Controls */}
-          <Collapsible open={isSettingsOpen} onOpenChange={setIsSettingsOpen}>
-            <div className="mb-6">
-              <CollapsibleTrigger asChild>
-                <Button
-                  variant="outline"
-                  className="w-full justify-between mb-2 h-auto py-3"
-                  data-testid="expand-filter-settings-button"
-                >
-                  <div className="flex items-center gap-2">
-                    <SettingsIcon className="w-4 h-4" />
-                    <span className="font-medium">Filter Settings</span>
-                    <span className="text-xs text-muted-foreground">
-                      ({sessions.length} sessions)
-                    </span>
-                  </div>
-                  <ChevronDownIcon
-                    className={`w-4 h-4 transition-transform ${
-                      isSettingsOpen ? "rotate-180" : ""
-                    }`}
-                  />
-                </Button>
-              </CollapsibleTrigger>
-              <CollapsibleContent>
-                <div className="p-4 bg-muted/50 rounded-lg border">
-                  <SettingsControls openingProjectId={projectId} />
-                </div>
-              </CollapsibleContent>
-            </div>
-          </Collapsible>
-
-          {sessions.length === 0 ? (
-            <Card>
-              <CardContent className="flex flex-col items-center justify-center py-12">
-                <MessageSquareIcon className="w-12 h-12 text-muted-foreground mb-4" />
-                <h3 className="text-lg font-medium mb-2">No sessions found</h3>
-                <p className="text-muted-foreground text-center max-w-md mb-6">
-                  No conversation sessions found for this project. Start a
-                  conversation with Claude Code in this project to create
-                  sessions.
-                </p>
-                <NewChatModal
-                  projectId={projectId}
-                  trigger={
-                    <Button size="lg" className="gap-2">
-                      <PlusIcon className="w-5 h-5" />
-                      Start First Chat
-                    </Button>
-                  }
-                />
-              </CardContent>
-            </Card>
-          ) : (
-            <div className="grid gap-4 md:grid-cols-1 lg:grid-cols-1">
-              {sessions.map((session) => (
-                <Card
-                  key={session.id}
-                  className="hover:shadow-md transition-shadow"
-                >
-                  <CardHeader>
-                    <CardTitle className="flex items-center gap-2">
-                      <span className="break-words overflow-ellipsis line-clamp-2 text-lg sm:text-xl">
-                        {session.meta.firstCommand !== null
-                          ? firstCommandToTitle(session.meta.firstCommand)
-                          : session.id}
-                      </span>
-                    </CardTitle>
-                    <CardDescription className="font-mono text-xs">
-                      {session.id}
-                    </CardDescription>
-                  </CardHeader>
-                  <CardContent className="space-y-2">
-                    <p className="text-sm text-muted-foreground">
-                      {session.meta.messageCount} messages
-                    </p>
-                    <p className="text-sm text-muted-foreground">
-                      Last modified:{" "}
-                      {session.lastModifiedAt
-                        ? new Date(session.lastModifiedAt).toLocaleDateString()
-                        : ""}
-                    </p>
-                    <p className="text-xs text-muted-foreground font-mono">
-                      {session.jsonlFilePath}
-                    </p>
-                  </CardContent>
-                  <CardContent className="pt-0">
-                    <Button asChild className="w-full">
-                      <Link
-                        href={`/projects/${projectId}/sessions/${encodeURIComponent(
-                          session.id,
-                        )}`}
-                      >
-                        View Session
-                      </Link>
-                    </Button>
-                  </CardContent>
-                </Card>
-              ))}
-            </div>
-          )}
-
-          {/* Load More Button */}
-          {sessions.length > 0 && hasNextPage && (
-            <div className="mt-6 flex justify-center">
-              <Button
-                onClick={() => fetchNextPage()}
-                disabled={isFetchingNextPage}
-                variant="outline"
-                size="lg"
-                className="min-w-[200px]"
-              >
-                {isFetchingNextPage ? "Loading..." : "Load More"}
-              </Button>
-            </div>
-          )}
-        </section>
-      </main>
-    </div>
-  );
-};
diff --git a/src/app/projects/[projectId]/components/chatForm/ChatInput.tsx b/src/app/projects/[projectId]/components/chatForm/ChatInput.tsx
index e707fd4..9d1fbdf 100644
--- a/src/app/projects/[projectId]/components/chatForm/ChatInput.tsx
+++ b/src/app/projects/[projectId]/components/chatForm/ChatInput.tsx
@@ -1,4 +1,9 @@
-import { AlertCircleIcon, LoaderIcon, SendIcon } from "lucide-react";
+import {
+  AlertCircleIcon,
+  LoaderIcon,
+  SendIcon,
+  SparklesIcon,
+} from "lucide-react";
 import { type FC, useCallback, useId, useRef, useState } from "react";
 import { Button } from "../../../../../components/ui/button";
 import { Textarea } from "../../../../../components/ui/textarea";
@@ -62,16 +67,28 @@ export const ChatInput: FC<ChatInputProps> = ({
 
     // IMEで変換中の場合は送信しない
     if (e.key === "Enter" && !e.nativeEvent.isComposing) {
-      const isEnterSend = config?.enterKeyBehavior === "enter-send";
+      const enterKeyBehavior = config?.enterKeyBehavior;
 
-      if (isEnterSend && !e.shiftKey) {
+      if (enterKeyBehavior === "enter-send" && !e.shiftKey && !e.metaKey) {
         // Enter: Send mode
         e.preventDefault();
         handleSubmit();
-      } else if (!isEnterSend && e.shiftKey) {
+      } else if (
+        enterKeyBehavior === "shift-enter-send" &&
+        e.shiftKey &&
+        !e.metaKey
+      ) {
         // Shift+Enter: Send mode (default)
         e.preventDefault();
         handleSubmit();
+      } else if (
+        enterKeyBehavior === "command-enter-send" &&
+        e.metaKey &&
+        !e.shiftKey
+      ) {
+        // Command+Enter: Send mode (Mac)
+        e.preventDefault();
+        handleSubmit();
       }
     }
   };
@@ -148,78 +165,98 @@ export const ChatInput: FC<ChatInputProps> = ({
   return (
     <div className={containerClassName}>
       {error && (
-        <div className="flex items-center gap-2 p-3 text-sm text-destructive bg-destructive/10 border border-destructive/20 rounded-md mb-4">
-          <AlertCircleIcon className="w-4 h-4" />
-          <span>Failed to send message. Please try again.</span>
+        <div className="flex items-center gap-2.5 px-4 py-3 text-sm text-red-600 dark:text-red-400 bg-gradient-to-r from-red-50 to-red-100/50 dark:from-red-950/30 dark:to-red-900/20 border border-red-200/50 dark:border-red-800/50 rounded-xl mb-4 animate-in fade-in slide-in-from-top-2 duration-300 shadow-sm">
+          <AlertCircleIcon className="w-4 h-4 shrink-0 mt-0.5" />
+          <span className="font-medium">
+            Failed to send message. Please try again.
+          </span>
         </div>
       )}
 
-      <div className="space-y-3">
-        <div className="relative" ref={containerRef}>
-          <Textarea
-            ref={textareaRef}
-            value={message}
-            onChange={(e) => {
-              if (
-                e.target.value.endsWith("@") ||
-                e.target.value.endsWith("/")
-              ) {
-                const position = getCursorPosition();
-                if (position) {
-                  setCursorPosition(position);
+      <div className="relative group">
+        <div
+          className="absolute -inset-0.5 bg-gradient-to-r from-blue-500/20 via-purple-500/20 to-pink-500/20 rounded-2xl blur opacity-0 group-hover:opacity-100 transition-opacity duration-500"
+          aria-hidden="true"
+        />
+
+        <div className="relative bg-background border border-border/40 rounded-2xl shadow-lg hover:shadow-xl transition-all duration-300 overflow-hidden">
+          <div className="relative" ref={containerRef}>
+            <Textarea
+              ref={textareaRef}
+              value={message}
+              onChange={(e) => {
+                if (
+                  e.target.value.endsWith("@") ||
+                  e.target.value.endsWith("/")
+                ) {
+                  const position = getCursorPosition();
+                  if (position) {
+                    setCursorPosition(position);
+                  }
                 }
-              }
 
-              setMessage(e.target.value);
-            }}
-            onKeyDown={handleKeyDown}
-            placeholder={placeholder}
-            className={`${minHeight} resize-none`}
-            disabled={isPending || disabled}
-            maxLength={4000}
-            aria-label="Message input with completion support"
-            aria-describedby={helpId}
-            aria-expanded={message.startsWith("/") || message.includes("@")}
-            aria-haspopup="listbox"
-            role="combobox"
-            aria-autocomplete="list"
-          />
-          <InlineCompletion
-            projectId={projectId}
-            message={message}
-            commandCompletionRef={commandCompletionRef}
-            fileCompletionRef={fileCompletionRef}
-            handleCommandSelect={handleCommandSelect}
-            handleFileSelect={handleFileSelect}
-            cursorPosition={cursorPosition}
-          />
-        </div>
-
-        <div className="flex items-center justify-between">
-          <span className="text-xs text-muted-foreground" id={helpId}>
-            {message.length}/4000 characters " • Use arrow keys to navigate
-            completions"
-          </span>
-
-          <Button
-            onClick={handleSubmit}
-            disabled={!message.trim() || isPending || disabled}
-            size={buttonSize}
-            className="gap-2"
-          >
-            {isPending ? (
-              <>
-                <LoaderIcon className="w-4 h-4 animate-spin" />
-                Sending... This may take a while.
-              </>
-            ) : (
-              <>
-                <SendIcon className="w-4 h-4" />
-                {buttonText}
-              </>
-            )}
-          </Button>
+                setMessage(e.target.value);
+              }}
+              onKeyDown={handleKeyDown}
+              placeholder={placeholder}
+              className={`${minHeight} resize-none border-0 focus-visible:ring-0 focus-visible:ring-offset-0 bg-transparent px-5 py-4 text-base transition-all duration-200 placeholder:text-muted-foreground/60`}
+              disabled={isPending || disabled}
+              maxLength={4000}
+              aria-label="Message input with completion support"
+              aria-describedby={helpId}
+              aria-expanded={message.startsWith("/") || message.includes("@")}
+              aria-haspopup="listbox"
+              role="combobox"
+              aria-autocomplete="list"
+            />
+          </div>
+
+          <div className="flex items-center justify-between gap-3 px-5 py-3 bg-muted/30 border-t border-border/40">
+            <div className="flex items-center gap-2">
+              <span
+                className="text-xs font-medium text-muted-foreground/80"
+                id={helpId}
+              >
+                {message.length}
+                <span className="text-muted-foreground/50">/4000</span>
+              </span>
+              {(message.startsWith("/") || message.includes("@")) && (
+                <span className="text-xs text-blue-600 dark:text-blue-400 font-medium flex items-center gap-1">
+                  <SparklesIcon className="w-3 h-3" />
+                  Autocomplete active
+                </span>
+              )}
+            </div>
+
+            <Button
+              onClick={handleSubmit}
+              disabled={!message.trim() || isPending || disabled}
+              size={buttonSize}
+              className="gap-2 transition-all duration-200 hover:shadow-md hover:scale-105 active:scale-95 bg-gradient-to-r from-blue-600 to-purple-600 hover:from-blue-500 hover:to-purple-500 disabled:from-muted disabled:to-muted"
+            >
+              {isPending ? (
+                <>
+                  <LoaderIcon className="w-4 h-4 animate-spin" />
+                  <span>Processing...</span>
+                </>
+              ) : (
+                <>
+                  <SendIcon className="w-4 h-4" />
+                  {buttonText}
+                </>
+              )}
+            </Button>
+          </div>
         </div>
+        <InlineCompletion
+          projectId={projectId}
+          message={message}
+          commandCompletionRef={commandCompletionRef}
+          fileCompletionRef={fileCompletionRef}
+          handleCommandSelect={handleCommandSelect}
+          handleFileSelect={handleFileSelect}
+          cursorPosition={cursorPosition}
+        />
       </div>
     </div>
   );
diff --git a/src/app/projects/[projectId]/components/chatForm/CommandCompletion.tsx b/src/app/projects/[projectId]/components/chatForm/CommandCompletion.tsx
index 7b5d931..316ed37 100644
--- a/src/app/projects/[projectId]/components/chatForm/CommandCompletion.tsx
+++ b/src/app/projects/[projectId]/components/chatForm/CommandCompletion.tsx
@@ -185,49 +185,53 @@ export const CommandCompletion = forwardRef<
         <CollapsibleContent>
           <div
             ref={listRef}
-            className="absolute z-50 w-full mt-1 bg-popover border border-border rounded-md shadow-lg max-h-48 overflow-y-auto"
+            className="absolute z-50 w-full bg-popover border border-border rounded-lg shadow-xl overflow-hidden"
+            style={{ height: "15rem" }}
             role="listbox"
             aria-label="Available commands"
           >
-            {filteredCommands.length > 0 && (
-              <div className="p-1">
-                <div
-                  className="px-2 py-1.5 text-xs font-medium text-muted-foreground border-b border-border mb-1 flex items-center gap-2"
-                  role="presentation"
-                >
-                  <TerminalIcon className="w-3 h-3" />
-                  Available Commands ({filteredCommands.length})
-                </div>
-                {filteredCommands.map((command, index) => (
-                  <Button
-                    key={command}
-                    variant="ghost"
-                    size="sm"
-                    className={cn(
-                      "w-full justify-start text-left font-mono text-sm h-8 px-2 min-w-0",
-                      index === selectedIndex &&
-                        "bg-accent text-accent-foreground",
-                    )}
-                    onClick={() => handleCommandSelect(command)}
-                    onMouseEnter={() => setSelectedIndex(index)}
-                    role="option"
-                    aria-selected={index === selectedIndex}
-                    aria-label={`Command: /${command}`}
-                    title={`/${command}`}
+            <div className="h-full overflow-y-auto">
+              {filteredCommands.length > 0 && (
+                <div className="p-1.5">
+                  <div
+                    className="px-3 py-2 text-xs font-semibold text-muted-foreground/80 border-b border-border/50 mb-1 flex items-center gap-2"
+                    role="presentation"
                   >
-                    <span className="text-muted-foreground mr-1 flex-shrink-0">
-                      /
-                    </span>
-                    <span className="font-medium truncate min-w-0">
-                      {command}
-                    </span>
-                    {index === selectedIndex && (
-                      <CheckIcon className="w-3 h-3 ml-auto text-primary flex-shrink-0" />
-                    )}
-                  </Button>
-                ))}
-              </div>
-            )}
+                    <TerminalIcon className="w-3.5 h-3.5" />
+                    Available Commands ({filteredCommands.length})
+                  </div>
+                  {filteredCommands.map((command, index) => (
+                    <Button
+                      key={command}
+                      variant="ghost"
+                      size="sm"
+                      className={cn(
+                        "w-full justify-start text-left font-mono text-sm h-9 px-3 min-w-0 transition-colors duration-150",
+                        index === selectedIndex
+                          ? "bg-gradient-to-r from-blue-500/10 to-purple-500/10 text-foreground border border-blue-500/20"
+                          : "hover:bg-accent/50",
+                      )}
+                      onClick={() => handleCommandSelect(command)}
+                      onMouseEnter={() => setSelectedIndex(index)}
+                      role="option"
+                      aria-selected={index === selectedIndex}
+                      aria-label={`Command: /${command}`}
+                      title={`/${command}`}
+                    >
+                      <span className="text-muted-foreground mr-1.5 flex-shrink-0">
+                        /
+                      </span>
+                      <span className="font-medium truncate min-w-0">
+                        {command}
+                      </span>
+                      {index === selectedIndex && (
+                        <CheckIcon className="w-3.5 h-3.5 ml-auto text-blue-600 dark:text-blue-400 flex-shrink-0" />
+                      )}
+                    </Button>
+                  ))}
+                </div>
+              )}
+            </div>
           </div>
         </CollapsibleContent>
       </Collapsible>
diff --git a/src/app/projects/[projectId]/components/chatForm/FileCompletion.tsx b/src/app/projects/[projectId]/components/chatForm/FileCompletion.tsx
index 9e095d8..807f084 100644
--- a/src/app/projects/[projectId]/components/chatForm/FileCompletion.tsx
+++ b/src/app/projects/[projectId]/components/chatForm/FileCompletion.tsx
@@ -259,63 +259,67 @@ export const FileCompletion = forwardRef<
         <CollapsibleContent>
           <div
             ref={listRef}
-            className="absolute z-50 w-full mt-1 bg-popover border border-border rounded-md shadow-lg max-h-48 overflow-y-auto"
+            className="absolute z-50 w-full bg-popover border border-border rounded-lg shadow-xl overflow-hidden"
+            style={{ height: "15rem" }}
             role="listbox"
             aria-label="Available files and directories"
           >
-            {filteredEntries.length > 0 && (
-              <div className="p-1">
-                <div
-                  className="px-2 py-1.5 text-xs font-medium text-muted-foreground border-b border-border mb-1 flex items-center gap-2"
-                  role="presentation"
-                >
-                  <FileIcon className="w-3 h-3" />
-                  Files & Directories ({filteredEntries.length})
-                  {basePath !== "/" && (
-                    <span className="text-xs font-mono text-muted-foreground/70">
-                      in {basePath}
-                    </span>
-                  )}
-                </div>
-                {filteredEntries.map((entry, index) => (
-                  <Button
-                    key={entry.path}
-                    variant="ghost"
-                    size="sm"
-                    className={cn(
-                      "w-full justify-start text-left font-mono text-sm h-8 px-2 min-w-0",
-                      index === selectedIndex &&
-                        "bg-accent text-accent-foreground",
-                    )}
-                    onClick={() =>
-                      handleEntrySelect(entry, entry.type === "file")
-                    }
-                    onMouseEnter={() => setSelectedIndex(index)}
-                    role="option"
-                    aria-selected={index === selectedIndex}
-                    aria-label={`${entry.type}: ${entry.name}`}
-                    title={entry.path}
+            <div className="h-full overflow-y-auto">
+              {filteredEntries.length > 0 && (
+                <div className="p-1.5">
+                  <div
+                    className="px-3 py-2 text-xs font-semibold text-muted-foreground/80 border-b border-border/50 mb-1 flex items-center gap-2"
+                    role="presentation"
                   >
-                    {entry.type === "directory" ? (
-                      <FolderIcon className="w-3 h-3 mr-2 text-blue-500 flex-shrink-0" />
-                    ) : (
-                      <FileIcon className="w-3 h-3 mr-2 text-gray-500 flex-shrink-0" />
-                    )}
-                    <span className="font-medium truncate min-w-0">
-                      {entry.name}
-                    </span>
-                    {entry.type === "directory" && (
-                      <span className="text-muted-foreground ml-1 flex-shrink-0">
-                        /
+                    <FileIcon className="w-3.5 h-3.5" />
+                    Files & Directories ({filteredEntries.length})
+                    {basePath !== "/" && (
+                      <span className="text-xs font-mono text-muted-foreground/70">
+                        in {basePath}
                       </span>
                     )}
-                    {index === selectedIndex && (
-                      <CheckIcon className="w-3 h-3 ml-auto text-primary flex-shrink-0" />
-                    )}
-                  </Button>
-                ))}
-              </div>
-            )}
+                  </div>
+                  {filteredEntries.map((entry, index) => (
+                    <Button
+                      key={entry.path}
+                      variant="ghost"
+                      size="sm"
+                      className={cn(
+                        "w-full justify-start text-left font-mono text-sm h-9 px-3 min-w-0 transition-colors duration-150",
+                        index === selectedIndex
+                          ? "bg-gradient-to-r from-blue-500/10 to-purple-500/10 text-foreground border border-blue-500/20"
+                          : "hover:bg-accent/50",
+                      )}
+                      onClick={() =>
+                        handleEntrySelect(entry, entry.type === "file")
+                      }
+                      onMouseEnter={() => setSelectedIndex(index)}
+                      role="option"
+                      aria-selected={index === selectedIndex}
+                      aria-label={`${entry.type}: ${entry.name}`}
+                      title={entry.path}
+                    >
+                      {entry.type === "directory" ? (
+                        <FolderIcon className="w-3.5 h-3.5 mr-2 text-blue-500 dark:text-blue-400 flex-shrink-0" />
+                      ) : (
+                        <FileIcon className="w-3.5 h-3.5 mr-2 text-gray-500 dark:text-gray-400 flex-shrink-0" />
+                      )}
+                      <span className="font-medium truncate min-w-0">
+                        {entry.name}
+                      </span>
+                      {entry.type === "directory" && (
+                        <span className="text-muted-foreground ml-1 flex-shrink-0">
+                          /
+                        </span>
+                      )}
+                      {index === selectedIndex && (
+                        <CheckIcon className="w-3.5 h-3.5 ml-auto text-blue-600 dark:text-blue-400 flex-shrink-0" />
+                      )}
+                    </Button>
+                  ))}
+                </div>
+              )}
+            </div>
           </div>
         </CollapsibleContent>
       </Collapsible>
diff --git a/src/app/projects/[projectId]/components/chatForm/InlineCompletion.tsx b/src/app/projects/[projectId]/components/chatForm/InlineCompletion.tsx
index c8de460..07c27a7 100644
--- a/src/app/projects/[projectId]/components/chatForm/InlineCompletion.tsx
+++ b/src/app/projects/[projectId]/components/chatForm/InlineCompletion.tsx
@@ -15,13 +15,21 @@ interface PositionStyle {
 const calculateOptimalPosition = (
   relativeCursorPosition: { top: number; left: number },
   absoluteCursorPosition: { top: number; left: number },
+  itemCount: number,
 ): PositionStyle => {
   const viewportHeight =
     typeof window !== "undefined" ? window.innerHeight : 800;
   const viewportCenter = viewportHeight / 2;
 
-  // Estimated completion height (we'll measure actual height later if needed)
-  const estimatedCompletionHeight = 200;
+  // Calculate dynamic height based on item count
+  // Header: ~48px, Each item: 36px (h-9), Padding: 12px
+  const headerHeight = 48;
+  const itemHeight = 36;
+  const padding = 12;
+  const maxItems = 5;
+  const visibleItems = Math.min(itemCount, maxItems);
+  const estimatedCompletionHeight =
+    headerHeight + itemHeight * visibleItems + padding;
 
   // Determine preferred placement based on viewport position
   const isInUpperHalf = absoluteCursorPosition.top < viewportCenter;
@@ -33,22 +41,22 @@ const calculateOptimalPosition = (
   let placement: "above" | "below";
   let top: number;
 
-  if (isInUpperHalf && spaceBelow >= estimatedCompletionHeight) {
+  if (isInUpperHalf && spaceBelow >= estimatedCompletionHeight + 20) {
     // Cursor in upper half and enough space below - place below
     placement = "below";
-    top = relativeCursorPosition.top + 16;
-  } else if (!isInUpperHalf && spaceAbove >= estimatedCompletionHeight) {
+    top = relativeCursorPosition.top + 24;
+  } else if (!isInUpperHalf && spaceAbove >= estimatedCompletionHeight + 20) {
     // Cursor in lower half and enough space above - place above
     placement = "above";
-    top = relativeCursorPosition.top - estimatedCompletionHeight - 8;
+    top = relativeCursorPosition.top - estimatedCompletionHeight - 16;
   } else {
     // Use whichever side has more space
     if (spaceBelow > spaceAbove) {
       placement = "below";
-      top = relativeCursorPosition.top + 16;
+      top = relativeCursorPosition.top + 24;
     } else {
       placement = "above";
-      top = relativeCursorPosition.top - estimatedCompletionHeight - 8;
+      top = relativeCursorPosition.top - estimatedCompletionHeight - 16;
     }
   }
 
@@ -93,6 +101,7 @@ export const InlineCompletion: FC<{
     return calculateOptimalPosition(
       cursorPosition.relative,
       cursorPosition.absolute,
+      5,
     );
   }, [cursorPosition]);
 
diff --git a/src/app/projects/[projectId]/components/newChat/NewChat.tsx b/src/app/projects/[projectId]/components/newChat/NewChat.tsx
index 6f73a1e..8be8e1e 100644
--- a/src/app/projects/[projectId]/components/newChat/NewChat.tsx
+++ b/src/app/projects/[projectId]/components/newChat/NewChat.tsx
@@ -17,10 +17,13 @@ export const NewChat: FC<{
   };
 
   const getPlaceholder = () => {
-    const isEnterSend = config?.enterKeyBehavior === "enter-send";
-    if (isEnterSend) {
+    const behavior = config?.enterKeyBehavior;
+    if (behavior === "enter-send") {
       return "Type your message here... (Start with / for commands, @ for files, Enter to send)";
     }
+    if (behavior === "command-enter-send") {
+      return "Type your message here... (Start with / for commands, @ for files, Command+Enter to send)";
+    }
     return "Type your message here... (Start with / for commands, @ for files, Shift+Enter to send)";
   };
 
@@ -33,7 +36,7 @@ export const NewChat: FC<{
       placeholder={getPlaceholder()}
       buttonText="Start Chat"
       minHeight="min-h-[200px]"
-      containerClassName="space-y-4"
+      containerClassName="p-6"
     />
   );
 };
diff --git a/src/app/projects/[projectId]/error.tsx b/src/app/projects/[projectId]/error.tsx
new file mode 100644
index 0000000..31a467e
--- /dev/null
+++ b/src/app/projects/[projectId]/error.tsx
@@ -0,0 +1,67 @@
+"use client";
+
+import { AlertCircle, ArrowLeft, RefreshCw } from "lucide-react";
+import { useRouter } from "next/navigation";
+
+import { Alert, AlertDescription, AlertTitle } from "@/components/ui/alert";
+import { Button } from "@/components/ui/button";
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from "@/components/ui/card";
+
+export default function ProjectErrorPage({
+  error,
+  reset,
+}: {
+  error: Error & { digest?: string };
+  reset: () => void;
+}) {
+  const router = useRouter();
+
+  return (
+    <div className="flex min-h-screen items-center justify-center p-4">
+      <Card className="w-full max-w-2xl">
+        <CardHeader>
+          <div className="flex items-center gap-3">
+            <AlertCircle className="size-6 text-destructive" />
+            <div>
+              <CardTitle>Failed to load project</CardTitle>
+              <CardDescription>
+                We encountered an error while loading this project
+              </CardDescription>
+            </div>
+          </div>
+        </CardHeader>
+        <CardContent className="space-y-4">
+          <Alert variant="destructive">
+            <AlertCircle />
+            <AlertTitle>Error Details</AlertTitle>
+            <AlertDescription>
+              <code className="text-xs">{error.message}</code>
+              {error.digest && (
+                <div className="mt-2 text-xs text-muted-foreground">
+                  Error ID: {error.digest}
+                </div>
+              )}
+            </AlertDescription>
+          </Alert>
+
+          <div className="flex gap-2">
+            <Button onClick={reset} variant="default">
+              <RefreshCw />
+              Try Again
+            </Button>
+            <Button onClick={() => router.push("/projects")} variant="outline">
+              <ArrowLeft />
+              Back to Projects
+            </Button>
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  );
+}
diff --git a/src/app/projects/[projectId]/latest/page.tsx b/src/app/projects/[projectId]/latest/page.tsx
new file mode 100644
index 0000000..18e3e68
--- /dev/null
+++ b/src/app/projects/[projectId]/latest/page.tsx
@@ -0,0 +1,27 @@
+import { QueryClient } from "@tanstack/react-query";
+import { redirect } from "next/navigation";
+import { latestSessionQuery } from "../../../../lib/api/queries";
+
+interface LatestSessionPageProps {
+  params: Promise<{ projectId: string }>;
+}
+
+export default async function LatestSessionPage({
+  params,
+}: LatestSessionPageProps) {
+  const { projectId } = await params;
+
+  const queryClient = new QueryClient();
+
+  const { latestSession } = await queryClient.fetchQuery(
+    latestSessionQuery(projectId),
+  );
+
+  if (!latestSession) {
+    redirect(`/projects`);
+  }
+
+  redirect(
+    `/projects/${encodeURIComponent(projectId)}/sessions/${encodeURIComponent(latestSession.id)}`,
+  );
+}
diff --git a/src/app/projects/[projectId]/not-found.tsx b/src/app/projects/[projectId]/not-found.tsx
new file mode 100644
index 0000000..e4cb3e3
--- /dev/null
+++ b/src/app/projects/[projectId]/not-found.tsx
@@ -0,0 +1,42 @@
+import { FolderSearch, Home } from "lucide-react";
+import Link from "next/link";
+
+import { Button } from "@/components/ui/button";
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from "@/components/ui/card";
+
+export default function ProjectNotFoundPage() {
+  return (
+    <div className="flex min-h-screen items-center justify-center p-4">
+      <Card className="w-full max-w-2xl">
+        <CardHeader>
+          <div className="flex items-center gap-3">
+            <FolderSearch className="size-6 text-muted-foreground" />
+            <div>
+              <CardTitle>Project Not Found</CardTitle>
+              <CardDescription>
+                The project you are looking for does not exist or has been
+                removed
+              </CardDescription>
+            </div>
+          </div>
+        </CardHeader>
+        <CardContent>
+          <div className="flex gap-2">
+            <Button asChild variant="default">
+              <Link href="/projects">
+                <Home />
+                Back to Projects
+              </Link>
+            </Button>
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  );
+}
diff --git a/src/app/projects/[projectId]/page.tsx b/src/app/projects/[projectId]/page.tsx
index d8b841b..16720b6 100644
--- a/src/app/projects/[projectId]/page.tsx
+++ b/src/app/projects/[projectId]/page.tsx
@@ -1,10 +1,4 @@
-import {
-  dehydrate,
-  HydrationBoundary,
-  QueryClient,
-} from "@tanstack/react-query";
-import { projectDetailQuery } from "../../../lib/api/queries";
-import { ProjectPageContent } from "./components/ProjectPage";
+import { redirect } from "next/navigation";
 
 interface ProjectPageProps {
   params: Promise<{ projectId: string }>;
@@ -12,20 +6,5 @@ interface ProjectPageProps {
 
 export default async function ProjectPage({ params }: ProjectPageProps) {
   const { projectId } = await params;
-
-  const queryClient = new QueryClient();
-
-  await queryClient.prefetchInfiniteQuery({
-    queryKey: ["projects", projectId],
-    queryFn: async ({ pageParam }) => {
-      return await projectDetailQuery(projectId, pageParam).queryFn();
-    },
-    initialPageParam: undefined as string | undefined,
-  });
-
-  return (
-    <HydrationBoundary state={dehydrate(queryClient)}>
-      <ProjectPageContent projectId={projectId} />
-    </HydrationBoundary>
-  );
+  redirect(`/projects/${encodeURIComponent(projectId)}/latest`);
 }
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/SessionPageContent.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/SessionPageContent.tsx
index 1c0a4f5..12e4435 100644
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/SessionPageContent.tsx
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/components/SessionPageContent.tsx
@@ -2,14 +2,12 @@
 
 import { useMutation } from "@tanstack/react-query";
 import {
-  ExternalLinkIcon,
   GitCompareIcon,
   LoaderIcon,
   MenuIcon,
   PauseIcon,
   XIcon,
 } from "lucide-react";
-import Link from "next/link";
 import type { FC } from "react";
 import { useEffect, useMemo, useRef, useState } from "react";
 import { PermissionDialog } from "@/components/PermissionDialog";
@@ -97,7 +95,7 @@ export const SessionPageContent: FC<{
   ]);
 
   return (
-    <div className="flex h-screen max-h-screen overflow-hidden">
+    <>
       <SessionSidebar
         currentSessionId={sessionId}
         projectId={projectId}
@@ -127,19 +125,12 @@ export const SessionPageContent: FC<{
 
             <div className="px-1 sm:px-5 flex flex-wrap items-center gap-1 sm:gap-2">
               {project?.claudeProjectPath && (
-                <Link
-                  href={`/projects/${projectId}`}
-                  target="_blank"
-                  className="transition-all duration-200"
+                <Badge
+                  variant="secondary"
+                  className="h-6 sm:h-8 text-xs sm:text-sm flex items-center"
                 >
-                  <Badge
-                    variant="secondary"
-                    className="h-6 sm:h-8 text-xs sm:text-sm flex items-center hover:bg-blue-50/60 hover:border-blue-300/60 hover:shadow-sm transition-all duration-200 cursor-pointer"
-                  >
-                    <ExternalLinkIcon className="w-3 h-3 sm:w-4 sm:h-4 mr-1" />
-                    {project.meta.projectPath ?? project.claudeProjectPath}
-                  </Badge>
-                </Link>
+                  {project.meta.projectPath ?? project.claudeProjectPath}
+                </Badge>
               )}
               <Badge
                 variant="secondary"
@@ -150,12 +141,18 @@ export const SessionPageContent: FC<{
             </div>
 
             {relatedSessionProcess?.status === "running" && (
-              <div className="flex items-center gap-1 sm:gap-2 p-1 bg-primary/10 border border-primary/20 rounded-lg mx-1 sm:mx-5">
-                <LoaderIcon className="w-3 h-3 sm:w-4 sm:h-4 animate-spin" />
+              <div className="flex items-center gap-1 sm:gap-2 p-1 bg-primary/10 border border-primary/20 rounded-lg mx-1 sm:mx-5 animate-in fade-in slide-in-from-top-2 duration-300">
+                <LoaderIcon className="w-3 h-3 sm:w-4 sm:h-4 animate-spin text-primary" />
                 <div className="flex-1">
                   <p className="text-xs sm:text-sm font-medium">
                     Conversation is in progress...
                   </p>
+                  <div className="w-full bg-primary/10 rounded-full h-1 mt-1 overflow-hidden">
+                    <div
+                      className="h-full bg-primary rounded-full animate-pulse"
+                      style={{ width: "70%" }}
+                    />
+                  </div>
                 </div>
                 <Button
                   variant="ghost"
@@ -163,18 +160,23 @@ export const SessionPageContent: FC<{
                   onClick={() => {
                     abortTask.mutate(relatedSessionProcess.id);
                   }}
+                  disabled={abortTask.isPending}
                 >
-                  <XIcon className="w-3 h-3 sm:w-4 sm:h-4" />
+                  {abortTask.isPending ? (
+                    <LoaderIcon className="w-3 h-3 sm:w-4 sm:h-4 animate-spin" />
+                  ) : (
+                    <XIcon className="w-3 h-3 sm:w-4 sm:h-4" />
+                  )}
                   <span className="hidden sm:inline">Abort</span>
                 </Button>
               </div>
             )}
 
             {relatedSessionProcess?.status === "paused" && (
-              <div className="flex items-center gap-1 sm:gap-2 p-1 bg-primary/10 border border-primary/20 rounded-lg mx-1 sm:mx-5">
-                <PauseIcon className="w-3 h-3 sm:w-4 sm:h-4" />
+              <div className="flex items-center gap-1 sm:gap-2 p-1 bg-orange-50/80 dark:bg-orange-950/50 border border-orange-300/50 dark:border-orange-800/50 rounded-lg mx-1 sm:mx-5 animate-in fade-in slide-in-from-top-2 duration-300">
+                <PauseIcon className="w-3 h-3 sm:w-4 sm:h-4 text-orange-600 dark:text-orange-400 animate-pulse" />
                 <div className="flex-1">
-                  <p className="text-xs sm:text-sm font-medium">
+                  <p className="text-xs sm:text-sm font-medium text-orange-900 dark:text-orange-200">
                     Conversation is paused...
                   </p>
                 </div>
@@ -184,8 +186,14 @@ export const SessionPageContent: FC<{
                   onClick={() => {
                     abortTask.mutate(relatedSessionProcess.id);
                   }}
+                  disabled={abortTask.isPending}
+                  className="hover:bg-orange-100 dark:hover:bg-orange-900/50 text-orange-900 dark:text-orange-200"
                 >
-                  <XIcon className="w-3 h-3 sm:w-4 sm:h-4" />
+                  {abortTask.isPending ? (
+                    <LoaderIcon className="w-3 h-3 sm:w-4 sm:h-4 animate-spin" />
+                  ) : (
+                    <XIcon className="w-3 h-3 sm:w-4 sm:h-4" />
+                  )}
                   <span className="hidden sm:inline">Abort</span>
                 </Button>
               </div>
@@ -204,16 +212,13 @@ export const SessionPageContent: FC<{
             />
 
             {relatedSessionProcess?.status === "running" && (
-              <div className="flex justify-start items-center py-8">
+              <div className="flex justify-start items-center py-8 animate-in fade-in duration-500">
                 <div className="flex flex-col items-center gap-4">
-                  <div className="flex items-center gap-2">
-                    <div className="flex gap-1">
-                      <div className="w-2 h-2 bg-primary rounded-full animate-bounce"></div>
-                      <div className="w-2 h-2 bg-primary rounded-full animate-bounce [animation-delay:0.1s]"></div>
-                      <div className="w-2 h-2 bg-primary rounded-full animate-bounce [animation-delay:0.2s]"></div>
-                    </div>
+                  <div className="relative">
+                    <LoaderIcon className="w-8 h-8 animate-spin text-primary" />
+                    <div className="absolute inset-0 rounded-full bg-primary/20 animate-ping" />
                   </div>
-                  <p className="text-sm text-muted-foreground font-medium">
+                  <p className="text-sm text-muted-foreground font-medium animate-pulse">
                     Claude Code is processing...
                   </p>
                 </div>
@@ -255,6 +260,6 @@ export const SessionPageContent: FC<{
         isOpen={isDialogOpen}
         onResponse={onPermissionResponse}
       />
-    </div>
+    </>
   );
 };
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/AssistantConversationContent.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/AssistantConversationContent.tsx
index 9aa6f4c..754fc94 100644
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/AssistantConversationContent.tsx
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/AssistantConversationContent.tsx
@@ -1,8 +1,14 @@
+"use client";
+
 import { ChevronDown, Lightbulb, Settings } from "lucide-react";
 import Image from "next/image";
+import { useTheme } from "next-themes";
 import type { FC } from "react";
 import { Prism as SyntaxHighlighter } from "react-syntax-highlighter";
-import { oneLight } from "react-syntax-highlighter/dist/esm/styles/prism";
+import {
+  oneDark,
+  oneLight,
+} from "react-syntax-highlighter/dist/esm/styles/prism";
 import { Badge } from "@/components/ui/badge";
 import {
   Card,
@@ -24,6 +30,8 @@ export const AssistantConversationContent: FC<{
   content: AssistantMessageContent;
   getToolResult: (toolUseId: string) => ToolResultContent | undefined;
 }> = ({ content, getToolResult }) => {
+  const { resolvedTheme } = useTheme();
+  const syntaxTheme = resolvedTheme === "dark" ? oneDark : oneLight;
   if (content.type === "text") {
     return (
       <div className="w-full mx-1 sm:mx-2 my-4 sm:my-6">
@@ -34,14 +42,16 @@ export const AssistantConversationContent: FC<{
 
   if (content.type === "thinking") {
     return (
-      <Card className="bg-muted/50 border-dashed gap-2 py-3 mb-2">
+      <Card className="bg-muted/50 border-dashed gap-2 py-3 mb-2 hover:shadow-sm transition-all duration-200">
         <Collapsible>
           <CollapsibleTrigger asChild>
-            <CardHeader className="cursor-pointer hover:bg-muted/80 rounded-t-lg transition-colors py-0 px-4">
+            <CardHeader className="cursor-pointer hover:bg-muted/80 rounded-t-lg transition-all duration-200 py-0 px-4 group">
               <div className="flex items-center gap-2">
-                <Lightbulb className="h-4 w-4 text-muted-foreground" />
-                <CardTitle className="text-sm font-medium">Thinking</CardTitle>
-                <ChevronDown className="h-4 w-4 text-muted-foreground transition-transform group-data-[state=open]:rotate-180" />
+                <Lightbulb className="h-4 w-4 text-muted-foreground group-hover:text-yellow-600 transition-colors" />
+                <CardTitle className="text-sm font-medium group-hover:text-foreground transition-colors">
+                  Thinking
+                </CardTitle>
+                <ChevronDown className="h-4 w-4 text-muted-foreground transition-transform duration-200 group-data-[state=open]:rotate-180" />
               </div>
             </CardHeader>
           </CollapsibleTrigger>
@@ -80,16 +90,16 @@ export const AssistantConversationContent: FC<{
         <CardContent className="space-y-2 py-0 px-4">
           <Collapsible>
             <CollapsibleTrigger asChild>
-              <div className="flex items-center justify-between cursor-pointer hover:bg-muted/50 rounded p-2 -mx-2">
-                <h4 className="text-xs font-medium text-muted-foreground">
+              <div className="flex items-center justify-between cursor-pointer hover:bg-muted/50 rounded p-2 -mx-2 transition-all duration-200 group">
+                <h4 className="text-xs font-medium text-muted-foreground group-hover:text-foreground">
                   Input Parameters
                 </h4>
-                <ChevronDown className="h-3 w-3 text-muted-foreground transition-transform group-data-[state=open]:rotate-180" />
+                <ChevronDown className="h-3 w-3 text-muted-foreground transition-transform duration-200 group-data-[state=open]:rotate-180" />
               </div>
             </CollapsibleTrigger>
             <CollapsibleContent>
               <SyntaxHighlighter
-                style={oneLight}
+                style={syntaxTheme}
                 language="json"
                 PreTag="div"
                 className="text-xs"
@@ -101,11 +111,11 @@ export const AssistantConversationContent: FC<{
           {toolResult && (
             <Collapsible>
               <CollapsibleTrigger asChild>
-                <div className="flex items-center justify-between cursor-pointer hover:bg-muted/50 rounded p-2 -mx-2">
-                  <h4 className="text-xs font-medium text-muted-foreground">
+                <div className="flex items-center justify-between cursor-pointer hover:bg-muted/50 rounded p-2 -mx-2 transition-all duration-200 group">
+                  <h4 className="text-xs font-medium text-muted-foreground group-hover:text-foreground">
                     Tool Result
                   </h4>
-                  <ChevronDown className="h-3 w-3 text-muted-foreground transition-transform group-data-[state=open]:rotate-180" />
+                  <ChevronDown className="h-3 w-3 text-muted-foreground transition-transform duration-200 group-data-[state=open]:rotate-180" />
                 </div>
               </CollapsibleTrigger>
               <CollapsibleContent>
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/ConversationList.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/ConversationList.tsx
index fd6a8c1..74e32bb 100644
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/ConversationList.tsx
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/ConversationList.tsx
@@ -143,7 +143,7 @@ export const ConversationList: FC<ConversationListProps> = ({
               conversation.type === "summary"
                 ? "justify-start"
                 : "justify-end"
-            }`}
+            } animate-in fade-in slide-in-from-bottom-2 duration-300`}
             key={getConversationKey(conversation)}
           >
             <div className="w-full max-w-3xl lg:max-w-4xl sm:w-[90%] md:w-[85%]">
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/UserTextContent.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/UserTextContent.tsx
index 753cb87..be68500 100644
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/UserTextContent.tsx
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/components/conversationList/UserTextContent.tsx
@@ -88,7 +88,7 @@ export const UserTextContent: FC<{ text: string; id?: string }> = ({
 
   return (
     <MarkdownContent
-      className="w-full px-3 py-3 mb-5 border border-border rounded-lg bg-slate-50"
+      className="w-full px-3 py-3 mb-5 border border-border rounded-lg bg-slate-50 dark:bg-slate-900/50"
       content={parsed.content}
     />
   );
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/resumeChat/ContinueChat.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/resumeChat/ContinueChat.tsx
index bdbf87f..65f0521 100644
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/resumeChat/ContinueChat.tsx
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/components/resumeChat/ContinueChat.tsx
@@ -21,26 +21,32 @@ export const ContinueChat: FC<{
   };
 
   const getPlaceholder = () => {
-    const isEnterSend = config?.enterKeyBehavior === "enter-send";
-    if (isEnterSend) {
-      return "Type your message... (Start with / for commands, Enter to send)";
+    const behavior = config?.enterKeyBehavior;
+    if (behavior === "enter-send") {
+      return "Type your message... (Start with / for commands, @ for files, Enter to send)";
     }
-    return "Type your message... (Start with / for commands, Shift+Enter to send)";
+    if (behavior === "command-enter-send") {
+      return "Type your message... (Start with / for commands, @ for files, Command+Enter to send)";
+    }
+    return "Type your message... (Start with / for commands, @ for files, Shift+Enter to send)";
   };
 
   return (
-    <div className="border-t border-border/50 bg-muted/20 p-4 mt-6">
-      <ChatInput
-        projectId={projectId}
-        onSubmit={handleSubmit}
-        isPending={continueSessionProcess.isPending}
-        error={continueSessionProcess.error}
-        placeholder={getPlaceholder()}
-        buttonText={"Send"}
-        minHeight="min-h-[100px]"
-        containerClassName="space-y-2"
-        buttonSize="default"
-      />
+    <div className="relative mt-8 mb-6">
+      <div className="absolute inset-0 bg-gradient-to-r from-transparent via-border to-transparent h-px top-0" />
+      <div className="pt-8">
+        <ChatInput
+          projectId={projectId}
+          onSubmit={handleSubmit}
+          isPending={continueSessionProcess.isPending}
+          error={continueSessionProcess.error}
+          placeholder={getPlaceholder()}
+          buttonText={"Send"}
+          minHeight="min-h-[120px]"
+          containerClassName=""
+          buttonSize="default"
+        />
+      </div>
     </div>
   );
 };
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/resumeChat/ResumeChat.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/resumeChat/ResumeChat.tsx
index b2a788e..c5baa22 100644
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/resumeChat/ResumeChat.tsx
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/components/resumeChat/ResumeChat.tsx
@@ -20,26 +20,32 @@ export const ResumeChat: FC<{
   };
 
   const getPlaceholder = () => {
-    const isEnterSend = config?.enterKeyBehavior === "enter-send";
-    if (isEnterSend) {
-      return "Type your message... (Start with / for commands, Enter to send)";
+    const behavior = config?.enterKeyBehavior;
+    if (behavior === "enter-send") {
+      return "Type your message... (Start with / for commands, @ for files, Enter to send)";
     }
-    return "Type your message... (Start with / for commands, Shift+Enter to send)";
+    if (behavior === "command-enter-send") {
+      return "Type your message... (Start with / for commands, @ for files, Command+Enter to send)";
+    }
+    return "Type your message... (Start with / for commands, @ for files, Shift+Enter to send)";
   };
 
   return (
-    <div className="border-t border-border/50 bg-muted/20 p-4 mt-6">
-      <ChatInput
-        projectId={projectId}
-        onSubmit={handleSubmit}
-        isPending={createSessionProcess.isPending}
-        error={createSessionProcess.error}
-        placeholder={getPlaceholder()}
-        buttonText={"Resume"}
-        minHeight="min-h-[100px]"
-        containerClassName="space-y-2"
-        buttonSize="default"
-      />
+    <div className="relative mt-8 mb-6">
+      <div className="absolute inset-0 bg-gradient-to-r from-transparent via-border to-transparent h-px top-0" />
+      <div className="pt-8">
+        <ChatInput
+          projectId={projectId}
+          onSubmit={handleSubmit}
+          isPending={createSessionProcess.isPending}
+          error={createSessionProcess.error}
+          placeholder={getPlaceholder()}
+          buttonText={"Resume"}
+          minHeight="min-h-[120px]"
+          containerClassName=""
+          buttonSize="default"
+        />
+      </div>
     </div>
   );
 };
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/MobileSidebar.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/MobileSidebar.tsx
index dca0e3c..461c563 100644
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/MobileSidebar.tsx
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/MobileSidebar.tsx
@@ -1,14 +1,15 @@
 "use client";
 
 import { MessageSquareIcon, PlugIcon, SettingsIcon, XIcon } from "lucide-react";
-import { type FC, useEffect, useState } from "react";
+import { type FC, Suspense, useEffect, useState } from "react";
 import { createPortal } from "react-dom";
+import { NotificationSettings } from "@/components/NotificationSettings";
+import { SettingsControls } from "@/components/SettingsControls";
 import { Button } from "@/components/ui/button";
 import { cn } from "@/lib/utils";
 import { useProject } from "../../../../hooks/useProject";
 import { McpTab } from "./McpTab";
 import { SessionsTab } from "./SessionsTab";
-import { SettingsTab } from "./SettingsTab";
 
 interface MobileSidebarProps {
   currentSessionId: string;
@@ -89,7 +90,35 @@ export const MobileSidebar: FC<MobileSidebarProps> = ({
       case "mcp":
         return <McpTab projectId={projectId} />;
       case "settings":
-        return <SettingsTab openingProjectId={projectId} />;
+        return (
+          <div className="h-full flex flex-col">
+            <Suspense
+              fallback={
+                <div className="flex-1 flex items-center justify-center p-4">
+                  <div className="text-sm text-sidebar-foreground/70">
+                    Loading settings...
+                  </div>
+                </div>
+              }
+            >
+              <div className="flex-1 overflow-y-auto p-4 space-y-6">
+                <div className="space-y-4">
+                  <h3 className="font-medium text-sm text-sidebar-foreground">
+                    Session Display
+                  </h3>
+                  <SettingsControls openingProjectId={projectId} />
+                </div>
+
+                <div className="space-y-4">
+                  <h3 className="font-medium text-sm text-sidebar-foreground">
+                    Notifications
+                  </h3>
+                  <NotificationSettings />
+                </div>
+              </div>
+            </Suspense>
+          </div>
+        );
       default:
         return null;
     }
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SessionSidebar.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SessionSidebar.tsx
index 4e08949..3bda11a 100644
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SessionSidebar.tsx
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SessionSidebar.tsx
@@ -1,19 +1,14 @@
 "use client";
 
-import {
-  MessageSquareIcon,
-  PlugIcon,
-  SettingsIcon,
-  Undo2Icon,
-} from "lucide-react";
-import { useRouter } from "next/navigation";
-import { type FC, useState } from "react";
+import { MessageSquareIcon, PlugIcon } from "lucide-react";
+import { type FC, useMemo } from "react";
+import type { SidebarTab } from "@/components/GlobalSidebar";
+import { GlobalSidebar } from "@/components/GlobalSidebar";
 import { cn } from "@/lib/utils";
 import { useProject } from "../../../../hooks/useProject";
 import { McpTab } from "./McpTab";
 import { MobileSidebar } from "./MobileSidebar";
 import { SessionsTab } from "./SessionsTab";
-import { SettingsTab } from "./SettingsTab";
 
 export const SessionSidebar: FC<{
   currentSessionId: string;
@@ -28,7 +23,6 @@ export const SessionSidebar: FC<{
   isMobileOpen = false,
   onMobileOpenChange,
 }) => {
-  const router = useRouter();
   const {
     data: projectData,
     fetchNextPage,
@@ -36,26 +30,14 @@ export const SessionSidebar: FC<{
     isFetchingNextPage,
   } = useProject(projectId);
   const sessions = projectData.pages.flatMap((page) => page.sessions);
-  const [activeTab, setActiveTab] = useState<"sessions" | "mcp" | "settings">(
-    "sessions",
-  );
-  const [isExpanded, setIsExpanded] = useState(true);
 
-  const handleTabClick = (tab: "sessions" | "mcp" | "settings") => {
-    if (activeTab === tab && isExpanded) {
-      // If clicking the active tab while expanded, collapse
-      setIsExpanded(false);
-    } else {
-      // If clicking a different tab or expanding, show that tab
-      setActiveTab(tab);
-      setIsExpanded(true);
-    }
-  };
-
-  const renderContent = () => {
-    switch (activeTab) {
-      case "sessions":
-        return (
+  const additionalTabs: SidebarTab[] = useMemo(
+    () => [
+      {
+        id: "sessions",
+        icon: MessageSquareIcon,
+        title: "Sessions",
+        content: (
           <SessionsTab
             sessions={sessions.map((session) => ({
               ...session,
@@ -67,105 +49,34 @@ export const SessionSidebar: FC<{
             isFetchingNextPage={isFetchingNextPage}
             onLoadMore={() => fetchNextPage()}
           />
-        );
-      case "mcp":
-        return <McpTab projectId={projectId} />;
-      case "settings":
-        return <SettingsTab openingProjectId={projectId} />;
-      default:
-        return null;
-    }
-  };
-
-  const sidebarContent = (
-    <div
-      className={cn(
-        "h-full border-r border-sidebar-border transition-all duration-300 ease-in-out flex bg-sidebar text-sidebar-foreground",
-        isExpanded ? "w-72 lg:w-80" : "w-12",
-      )}
-    >
-      {/* Vertical Icon Menu - Always Visible */}
-      <div className="w-12 flex flex-col border-r border-sidebar-border bg-sidebar/50">
-        <div className="flex flex-col p-2 space-y-1">
-          <button
-            type="button"
-            onClick={() => {
-              router.push(`/projects/${projectId}`);
-            }}
-            className={cn(
-              "w-8 h-8 flex items-center justify-center rounded-md transition-colors",
-              "hover:bg-sidebar-accent hover:text-sidebar-accent-foreground",
-              "text-sidebar-foreground/70",
-            )}
-            title="Back to Project"
-          >
-            <Undo2Icon className="w-4 h-4" />
-          </button>
-
-          <button
-            type="button"
-            onClick={() => handleTabClick("sessions")}
-            className={cn(
-              "w-8 h-8 flex items-center justify-center rounded-md transition-colors",
-              "hover:bg-sidebar-accent hover:text-sidebar-accent-foreground",
-              activeTab === "sessions" && isExpanded
-                ? "bg-sidebar-accent text-sidebar-accent-foreground shadow-sm"
-                : "text-sidebar-foreground/70",
-            )}
-            title="Sessions"
-            data-testid="sessions-tab-button"
-          >
-            <MessageSquareIcon className="w-4 h-4" />
-          </button>
-
-          <button
-            type="button"
-            onClick={() => handleTabClick("mcp")}
-            className={cn(
-              "w-8 h-8 flex items-center justify-center rounded-md transition-colors",
-              "hover:bg-sidebar-accent hover:text-sidebar-accent-foreground",
-              activeTab === "mcp" && isExpanded
-                ? "bg-sidebar-accent text-sidebar-accent-foreground shadow-sm"
-                : "text-sidebar-foreground/70",
-            )}
-            title="MCP Servers"
-            data-testid="mcp-tab-button"
-          >
-            <PlugIcon className="w-4 h-4" />
-          </button>
-
-          <button
-            type="button"
-            onClick={() => handleTabClick("settings")}
-            className={cn(
-              "w-8 h-8 flex items-center justify-center rounded-md transition-colors",
-              "hover:bg-sidebar-accent hover:text-sidebar-accent-foreground",
-              activeTab === "settings" && isExpanded
-                ? "bg-sidebar-accent text-sidebar-accent-foreground shadow-sm"
-                : "text-sidebar-foreground/70",
-            )}
-            title="Settings"
-            data-testid="settings-tab-button"
-          >
-            <SettingsIcon className="w-4 h-4" />
-          </button>
-        </div>
-      </div>
-
-      {/* Content Area - Only shown when expanded */}
-      {isExpanded && (
-        <div className="flex-1 flex flex-col overflow-hidden">
-          {renderContent()}
-        </div>
-      )}
-    </div>
+        ),
+      },
+      {
+        id: "mcp",
+        icon: PlugIcon,
+        title: "MCP Servers",
+        content: <McpTab projectId={projectId} />,
+      },
+    ],
+    [
+      sessions,
+      currentSessionId,
+      projectId,
+      hasNextPage,
+      isFetchingNextPage,
+      fetchNextPage,
+    ],
   );
 
   return (
     <>
       {/* Desktop sidebar */}
       <div className={cn("hidden md:flex h-full", className)}>
-        {sidebarContent}
+        <GlobalSidebar
+          projectId={projectId}
+          additionalTabs={additionalTabs}
+          defaultActiveTab="sessions"
+        />
       </div>
 
       {/* Mobile sidebar */}
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SessionsTab.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SessionsTab.tsx
index fd99fbd..92e2613 100644
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SessionsTab.tsx
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SessionsTab.tsx
@@ -103,9 +103,9 @@ export const SessionsTab: FC<{
                 session.id,
               )}`}
               className={cn(
-                "block rounded-lg p-2.5 transition-all duration-200 hover:bg-blue-50/60 hover:border-blue-300/60 hover:shadow-sm border border-sidebar-border/40 bg-sidebar/30",
+                "block rounded-lg p-2.5 transition-all duration-200 hover:bg-blue-50/60 dark:hover:bg-blue-950/40 hover:border-blue-300/60 dark:hover:border-blue-700/60 hover:shadow-sm border border-sidebar-border/40 bg-sidebar/30",
                 isActive &&
-                  "bg-blue-100 border-blue-400 shadow-md ring-1 ring-blue-200/50 hover:bg-blue-100 hover:border-blue-400",
+                  "bg-blue-100 dark:bg-blue-900/50 border-blue-400 dark:border-blue-600 shadow-md ring-1 ring-blue-200/50 dark:ring-blue-700/50 hover:bg-blue-100 dark:hover:bg-blue-900/50 hover:border-blue-400 dark:hover:border-blue-600",
               )}
             >
               <div className="space-y-1.5">
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SettingsTab.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SettingsTab.tsx
deleted file mode 100644
index dd1b932..0000000
--- a/src/app/projects/[projectId]/sessions/[sessionId]/components/sessionSidebar/SettingsTab.tsx
+++ /dev/null
@@ -1,40 +0,0 @@
-"use client";
-
-import type { FC } from "react";
-import { NotificationSettings } from "@/components/NotificationSettings";
-import { SettingsControls } from "@/components/SettingsControls";
-
-export const SettingsTab: FC<{
-  openingProjectId: string;
-}> = ({ openingProjectId }) => {
-  return (
-    <div className="h-full flex flex-col">
-      <div className="border-b border-sidebar-border p-4">
-        <h2 className="font-semibold text-lg">Settings</h2>
-        <p className="text-xs text-sidebar-foreground/70">
-          Display and behavior preferences
-        </p>
-      </div>
-
-      <div className="flex-1 overflow-y-auto p-4 space-y-6">
-        {/* Session Display Settings */}
-        <div className="space-y-4">
-          <h3 className="font-medium text-sm text-sidebar-foreground">
-            Session Display
-          </h3>
-
-          <SettingsControls openingProjectId={openingProjectId} />
-        </div>
-
-        {/* Notification Settings */}
-        <div className="space-y-4">
-          <h3 className="font-medium text-sm text-sidebar-foreground">
-            Notifications
-          </h3>
-
-          <NotificationSettings />
-        </div>
-      </div>
-    </div>
-  );
-};
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/error.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/error.tsx
new file mode 100644
index 0000000..6ed849a
--- /dev/null
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/error.tsx
@@ -0,0 +1,72 @@
+"use client";
+
+import { AlertCircle, ArrowLeft, RefreshCw } from "lucide-react";
+import { useParams, useRouter } from "next/navigation";
+
+import { Alert, AlertDescription, AlertTitle } from "@/components/ui/alert";
+import { Button } from "@/components/ui/button";
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from "@/components/ui/card";
+
+export default function SessionErrorPage({
+  error,
+  reset,
+}: {
+  error: Error & { digest?: string };
+  reset: () => void;
+}) {
+  const router = useRouter();
+  const params = useParams<{ projectId: string }>();
+  const projectId = params.projectId;
+
+  return (
+    <div className="flex min-h-screen items-center justify-center p-4">
+      <Card className="w-full max-w-2xl">
+        <CardHeader>
+          <div className="flex items-center gap-3">
+            <AlertCircle className="size-6 text-destructive" />
+            <div>
+              <CardTitle>Failed to load session</CardTitle>
+              <CardDescription>
+                We encountered an error while loading this conversation session
+              </CardDescription>
+            </div>
+          </div>
+        </CardHeader>
+        <CardContent className="space-y-4">
+          <Alert variant="destructive">
+            <AlertCircle />
+            <AlertTitle>Error Details</AlertTitle>
+            <AlertDescription>
+              <code className="text-xs">{error.message}</code>
+              {error.digest && (
+                <div className="mt-2 text-xs text-muted-foreground">
+                  Error ID: {error.digest}
+                </div>
+              )}
+            </AlertDescription>
+          </Alert>
+
+          <div className="flex gap-2">
+            <Button onClick={reset} variant="default">
+              <RefreshCw />
+              Try Again
+            </Button>
+            <Button
+              onClick={() => router.push(`/projects/${projectId}`)}
+              variant="outline"
+            >
+              <ArrowLeft />
+              Back to Project
+            </Button>
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  );
+}
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/layout.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/layout.tsx
new file mode 100644
index 0000000..a54cd69
--- /dev/null
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/layout.tsx
@@ -0,0 +1,15 @@
+"use client";
+
+import type { FC, ReactNode } from "react";
+
+interface SessionLayoutProps {
+  children: ReactNode;
+}
+
+const SessionLayout: FC<SessionLayoutProps> = ({ children }) => {
+  return (
+    <div className="flex h-screen max-h-screen overflow-hidden">{children}</div>
+  );
+};
+
+export default SessionLayout;
diff --git a/src/app/projects/[projectId]/sessions/[sessionId]/not-found.tsx b/src/app/projects/[projectId]/sessions/[sessionId]/not-found.tsx
new file mode 100644
index 0000000..127b242
--- /dev/null
+++ b/src/app/projects/[projectId]/sessions/[sessionId]/not-found.tsx
@@ -0,0 +1,42 @@
+import { MessageCircleOff } from "lucide-react";
+import Link from "next/link";
+
+import { Button } from "@/components/ui/button";
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from "@/components/ui/card";
+
+export default function SessionNotFoundPage() {
+  return (
+    <div className="flex min-h-screen items-center justify-center p-4">
+      <Card className="w-full max-w-2xl">
+        <CardHeader>
+          <div className="flex items-center gap-3">
+            <MessageCircleOff className="size-6 text-muted-foreground" />
+            <div>
+              <CardTitle>Session Not Found</CardTitle>
+              <CardDescription>
+                The conversation session you are looking for does not exist or
+                has been removed
+              </CardDescription>
+            </div>
+          </div>
+        </CardHeader>
+        <CardContent>
+          <div className="flex gap-2">
+            <Button asChild variant="default">
+              <Link href="/projects">
+                <MessageCircleOff />
+                Back to Projects
+              </Link>
+            </Button>
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  );
+}
diff --git a/src/app/projects/components/ProjectList.tsx b/src/app/projects/components/ProjectList.tsx
index eb4fa1b..e4e10d9 100644
--- a/src/app/projects/components/ProjectList.tsx
+++ b/src/app/projects/components/ProjectList.tsx
@@ -59,8 +59,8 @@ export const ProjectList: FC = () => {
           </CardContent>
           <CardContent className="pt-0">
             <Button asChild className="w-full">
-              <Link href={`/projects/${encodeURIComponent(project.id)}`}>
-                View Sessions
+              <Link href={`/projects/${encodeURIComponent(project.id)}/latest`}>
+                View Conversations
               </Link>
             </Button>
           </CardContent>
diff --git a/src/app/projects/page.tsx b/src/app/projects/page.tsx
index bb8602f..38f4c8a 100644
--- a/src/app/projects/page.tsx
+++ b/src/app/projects/page.tsx
@@ -1,38 +1,48 @@
-import { QueryClient } from "@tanstack/react-query";
+"use client";
+
 import { HistoryIcon } from "lucide-react";
-import { projectListQuery } from "../../lib/api/queries";
+import { Suspense } from "react";
+import { GlobalSidebar } from "@/components/GlobalSidebar";
 import { ProjectList } from "./components/ProjectList";
 
 export const dynamic = "force-dynamic";
 export const fetchCache = "force-no-store";
 
-export default async function ProjectsPage() {
-  const queryClient = new QueryClient();
-
-  await queryClient.prefetchQuery({
-    queryKey: projectListQuery.queryKey,
-    queryFn: projectListQuery.queryFn,
-  });
-
+export default function ProjectsPage() {
   return (
-    <div className="container mx-auto px-4 py-8">
-      <header className="mb-8">
-        <h1 className="text-3xl font-bold mb-2 flex items-center gap-2">
-          <HistoryIcon className="w-8 h-8" />
-          Claude Code Viewer
-        </h1>
-        <p className="text-muted-foreground">
-          Browse your Claude Code conversation history and project interactions
-        </p>
-      </header>
+    <div className="flex h-screen max-h-screen overflow-hidden">
+      <GlobalSidebar className="hidden md:flex" />
+      <div className="flex-1 overflow-auto">
+        <div className="container mx-auto px-4 py-8">
+          <header className="mb-8">
+            <h1 className="text-3xl font-bold mb-2 flex items-center gap-2">
+              <HistoryIcon className="w-8 h-8" />
+              Claude Code Viewer
+            </h1>
+            <p className="text-muted-foreground">
+              Browse your Claude Code conversation history and project
+              interactions
+            </p>
+          </header>
 
-      <main>
-        <section>
-          <h2 className="text-xl font-semibold mb-4">Your Projects</h2>
-
-          <ProjectList />
-        </section>
-      </main>
+          <main>
+            <section>
+              <h2 className="text-xl font-semibold mb-4">Your Projects</h2>
+              <Suspense
+                fallback={
+                  <div className="flex items-center justify-center py-12">
+                    <div className="text-muted-foreground">
+                      Loading projects...
+                    </div>
+                  </div>
+                }
+              >
+                <ProjectList />
+              </Suspense>
+            </section>
+          </main>
+        </div>
+      </div>
     </div>
   );
 }
diff --git a/src/components/GlobalSidebar.tsx b/src/components/GlobalSidebar.tsx
new file mode 100644
index 0000000..4834d2f
--- /dev/null
+++ b/src/components/GlobalSidebar.tsx
@@ -0,0 +1,132 @@
+"use client";
+
+import type { LucideIcon } from "lucide-react";
+import { SettingsIcon } from "lucide-react";
+import { type FC, type ReactNode, Suspense, useState } from "react";
+import { cn } from "@/lib/utils";
+import { NotificationSettings } from "./NotificationSettings";
+import { SettingsControls } from "./SettingsControls";
+
+export interface SidebarTab {
+  id: string;
+  icon: LucideIcon;
+  title: string;
+  content: ReactNode;
+}
+
+interface GlobalSidebarProps {
+  projectId?: string;
+  className?: string;
+  additionalTabs?: SidebarTab[];
+  defaultActiveTab?: string;
+}
+
+export const GlobalSidebar: FC<GlobalSidebarProps> = ({
+  projectId,
+  className,
+  additionalTabs = [],
+  defaultActiveTab,
+}) => {
+  const settingsTab: SidebarTab = {
+    id: "settings",
+    icon: SettingsIcon,
+    title: "Settings",
+    content: (
+      <div className="h-full flex flex-col">
+        <div className="border-b border-sidebar-border p-4">
+          <h2 className="font-semibold text-lg">Settings</h2>
+          <p className="text-xs text-sidebar-foreground/70">
+            Display and behavior preferences
+          </p>
+        </div>
+
+        <Suspense
+          fallback={
+            <div className="flex-1 flex items-center justify-center p-4">
+              <div className="text-sm text-sidebar-foreground/70">
+                Loading settings...
+              </div>
+            </div>
+          }
+        >
+          <div className="flex-1 overflow-y-auto p-4 space-y-6">
+            <div className="space-y-4">
+              <h3 className="font-medium text-sm text-sidebar-foreground">
+                Session Display
+              </h3>
+              <SettingsControls openingProjectId={projectId ?? ""} />
+            </div>
+
+            <div className="space-y-4">
+              <h3 className="font-medium text-sm text-sidebar-foreground">
+                Notifications
+              </h3>
+              <NotificationSettings />
+            </div>
+          </div>
+        </Suspense>
+      </div>
+    ),
+  };
+
+  const allTabs = [...additionalTabs, settingsTab];
+  const [activeTab, setActiveTab] = useState<string>(
+    defaultActiveTab ?? allTabs[allTabs.length - 1]?.id ?? "settings",
+  );
+  const [isExpanded, setIsExpanded] = useState(!!defaultActiveTab);
+
+  const handleTabClick = (tabId: string) => {
+    if (activeTab === tabId && isExpanded) {
+      setIsExpanded(false);
+    } else {
+      setActiveTab(tabId);
+      setIsExpanded(true);
+    }
+  };
+
+  const activeTabContent = allTabs.find((tab) => tab.id === activeTab)?.content;
+
+  return (
+    <div
+      className={cn(
+        "h-full border-r border-sidebar-border transition-all duration-300 ease-in-out flex bg-sidebar text-sidebar-foreground",
+        isExpanded ? "w-72 lg:w-80" : "w-12",
+        className,
+      )}
+    >
+      {/* Vertical Icon Menu - Always Visible */}
+      <div className="w-12 flex flex-col border-r border-sidebar-border bg-sidebar/50">
+        <div className="flex flex-col p-2 space-y-1">
+          {allTabs.map((tab) => {
+            const Icon = tab.icon;
+            return (
+              <button
+                key={tab.id}
+                type="button"
+                onClick={() => handleTabClick(tab.id)}
+                className={cn(
+                  "w-8 h-8 flex items-center justify-center rounded-md transition-colors",
+                  "hover:bg-sidebar-accent hover:text-sidebar-accent-foreground",
+                  activeTab === tab.id && isExpanded
+                    ? "bg-sidebar-accent text-sidebar-accent-foreground shadow-sm"
+                    : "text-sidebar-foreground/70",
+                )}
+                title={tab.title}
+                data-testid={`${tab.id}-tab-button`}
+              >
+                <Icon className="w-4 h-4" />
+              </button>
+            );
+          })}
+        </div>
+      </div>
+
+      {/* Content Area - Only shown when expanded */}
+      {isExpanded && (
+        <div className="flex-1 flex flex-col overflow-hidden">
+          {activeTabContent}
+        </div>
+      )}
+    </div>
+  );
+};
diff --git a/src/components/SettingsControls.tsx b/src/components/SettingsControls.tsx
index b9c849d..d1f23ef 100644
--- a/src/components/SettingsControls.tsx
+++ b/src/components/SettingsControls.tsx
@@ -1,6 +1,7 @@
 "use client";
 
 import { useQueryClient } from "@tanstack/react-query";
+import { useTheme } from "next-themes";
 import { type FC, useCallback, useId } from "react";
 import { useConfig } from "@/app/hooks/useConfig";
 import { Checkbox } from "@/components/ui/checkbox";
@@ -33,8 +34,10 @@ export const SettingsControls: FC<SettingsControlsProps> = ({
   const checkboxId = useId();
   const enterKeyBehaviorId = useId();
   const permissionModeId = useId();
+  const themeId = useId();
   const { config, updateConfig } = useConfig();
   const queryClient = useQueryClient();
+  const { theme, setTheme } = useTheme();
 
   const onConfigChanged = useCallback(async () => {
     await queryClient.refetchQueries({
@@ -69,7 +72,10 @@ export const SettingsControls: FC<SettingsControlsProps> = ({
   const handleEnterKeyBehaviorChange = async (value: string) => {
     const newConfig = {
       ...config,
-      enterKeyBehavior: value as "shift-enter-send" | "enter-send",
+      enterKeyBehavior: value as
+        | "shift-enter-send"
+        | "enter-send"
+        | "command-enter-send",
     };
     updateConfig(newConfig);
     await onConfigChanged();
@@ -154,6 +160,9 @@ export const SettingsControls: FC<SettingsControlsProps> = ({
               Shift+Enter to send (default)
             </SelectItem>
             <SelectItem value="enter-send">Enter to send</SelectItem>
+            <SelectItem value="command-enter-send">
+              Command+Enter to send
+            </SelectItem>
           </SelectContent>
         </Select>
         {showDescriptions && (
@@ -197,6 +206,29 @@ export const SettingsControls: FC<SettingsControlsProps> = ({
           </p>
         )}
       </div>
+
+      <div className="space-y-2">
+        {showLabels && (
+          <label htmlFor={themeId} className="text-sm font-medium leading-none">
+            Theme
+          </label>
+        )}
+        <Select value={theme || "system"} onValueChange={setTheme}>
+          <SelectTrigger id={themeId} className="w-full">
+            <SelectValue placeholder="Select theme" />
+          </SelectTrigger>
+          <SelectContent>
+            <SelectItem value="light">Light</SelectItem>
+            <SelectItem value="dark">Dark</SelectItem>
+            <SelectItem value="system">System</SelectItem>
+          </SelectContent>
+        </Select>
+        {showDescriptions && (
+          <p className="text-xs text-muted-foreground mt-1">
+            Choose your preferred color theme
+          </p>
+        )}
+      </div>
     </div>
   );
 };
diff --git a/src/lib/api/queries.ts b/src/lib/api/queries.ts
index 2a75bdc..9abf7fe 100644
--- a/src/lib/api/queries.ts
+++ b/src/lib/api/queries.ts
@@ -33,6 +33,26 @@ export const projectDetailQuery = (projectId: string, cursor?: string) =>
     },
   }) as const;
 
+export const latestSessionQuery = (projectId: string) =>
+  ({
+    queryKey: ["projects", projectId, "latest-session"],
+    queryFn: async () => {
+      const response = await honoClient.api.projects[":projectId"][
+        "latest-session"
+      ].$get({
+        param: { projectId },
+      });
+
+      if (!response.ok) {
+        throw new Error(
+          `Failed to fetch latest session: ${response.statusText}`,
+        );
+      }
+
+      return response.json();
+    },
+  }) as const;
+
 export const sessionDetailQuery = (projectId: string, sessionId: string) =>
   ({
     queryKey: ["projects", projectId, "sessions", sessionId],
diff --git a/src/lib/sse/hook/useServerEventListener.ts b/src/lib/sse/hook/useServerEventListener.ts
index 293bf12..cb1c778 100644
--- a/src/lib/sse/hook/useServerEventListener.ts
+++ b/src/lib/sse/hook/useServerEventListener.ts
@@ -1,4 +1,4 @@
-import { useEffect } from "react";
+import { useEffect, useRef } from "react";
 import type { SSEEvent } from "../../../types/sse";
 import { type EventListener, useSSEContext } from "../SSEContext";
 
@@ -6,19 +6,24 @@ import { type EventListener, useSSEContext } from "../SSEContext";
  * Custom hook to listen for specific SSE events
  * @param eventType - The type of event to listen for
  * @param listener - The callback function to execute when the event is received
- * @param deps - Dependencies array for the listener function (similar to useEffect)
  */
 export const useServerEventListener = <T extends SSEEvent["kind"]>(
   eventType: T,
   listener: EventListener<T>,
-  deps?: React.DependencyList,
 ) => {
   const { addEventListener } = useSSEContext();
+  const listenerRef = useRef(listener);
 
   useEffect(() => {
-    const removeEventListener = addEventListener(eventType, listener);
+    listenerRef.current = listener;
+  });
+
+  useEffect(() => {
+    const removeEventListener = addEventListener(eventType, (event) => {
+      listenerRef.current(event);
+    });
     return () => {
       removeEventListener();
     };
-  }, [eventType, addEventListener, listener, ...(deps ?? [])]);
+  }, [eventType, addEventListener]);
 };
diff --git a/src/server/config/config.ts b/src/server/config/config.ts
index aefa6b8..021c0c9 100644
--- a/src/server/config/config.ts
+++ b/src/server/config/config.ts
@@ -4,7 +4,7 @@ export const configSchema = z.object({
   hideNoUserMessageSession: z.boolean().optional().default(true),
   unifySameTitleSession: z.boolean().optional().default(true),
   enterKeyBehavior: z
-    .enum(["shift-enter-send", "enter-send"])
+    .enum(["shift-enter-send", "enter-send", "command-enter-send"])
     .optional()
     .default("shift-enter-send"),
   permissionMode: z
diff --git a/src/server/hono/initialize.test.ts b/src/server/hono/initialize.test.ts
index e3515a7..9f7c2c5 100644
--- a/src/server/hono/initialize.test.ts
+++ b/src/server/hono/initialize.test.ts
@@ -5,9 +5,9 @@ import { FileWatcherService } from "../service/events/fileWatcher";
 import type { InternalEventDeclaration } from "../service/events/InternalEventDeclaration";
 import { ProjectMetaService } from "../service/project/ProjectMetaService";
 import { ProjectRepository } from "../service/project/ProjectRepository";
-import { VirtualConversationDatabase } from "../service/session/PredictSessionsDatabase";
 import { SessionMetaService } from "../service/session/SessionMetaService";
 import { SessionRepository } from "../service/session/SessionRepository";
+import { VirtualConversationDatabase } from "../service/session/VirtualConversationDatabase";
 import { InitializeService } from "./initialize";
 
 describe("InitializeService", () => {
diff --git a/src/server/hono/initialize.ts b/src/server/hono/initialize.ts
index ab11261..56d6074 100644
--- a/src/server/hono/initialize.ts
+++ b/src/server/hono/initialize.ts
@@ -4,9 +4,9 @@ import { FileWatcherService } from "../service/events/fileWatcher";
 import type { InternalEventDeclaration } from "../service/events/InternalEventDeclaration";
 import { ProjectMetaService } from "../service/project/ProjectMetaService";
 import { ProjectRepository } from "../service/project/ProjectRepository";
-import { VirtualConversationDatabase } from "../service/session/PredictSessionsDatabase";
 import { SessionMetaService } from "../service/session/SessionMetaService";
 import { SessionRepository } from "../service/session/SessionRepository";
+import { VirtualConversationDatabase } from "../service/session/VirtualConversationDatabase";
 
 interface InitializeServiceInterface {
   readonly startInitialization: () => Effect.Effect<void>;
diff --git a/src/server/hono/route.ts b/src/server/hono/route.ts
index 3a809ee..8912666 100644
--- a/src/server/hono/route.ts
+++ b/src/server/hono/route.ts
@@ -24,9 +24,9 @@ import { getMcpList } from "../service/mcp/getMcpList";
 import { claudeCommandsDirPath } from "../service/paths";
 import type { ProjectMetaService } from "../service/project/ProjectMetaService";
 import { ProjectRepository } from "../service/project/ProjectRepository";
-import type { VirtualConversationDatabase } from "../service/session/PredictSessionsDatabase";
 import type { SessionMetaService } from "../service/session/SessionMetaService";
 import { SessionRepository } from "../service/session/SessionRepository";
+import type { VirtualConversationDatabase } from "../service/session/VirtualConversationDatabase";
 import type { HonoAppType } from "./app";
 import { InitializeService } from "./initialize";
 import { configMiddleware } from "./middleware/config.middleware";
@@ -184,6 +184,24 @@ export const routes = (app: HonoAppType) =>
           },
         )
 
+        .get("/projects/:projectId/latest-session", async (c) => {
+          const { projectId } = c.req.param();
+
+          const program = Effect.gen(function* () {
+            const { sessions } = yield* sessionRepository.getSessions(
+              projectId,
+              { maxCount: 1 },
+            );
+
+            return {
+              latestSession: sessions[0] ?? null,
+            };
+          });
+
+          const result = await Runtime.runPromise(runtime)(program);
+          return c.json(result);
+        })
+
         .get("/projects/:projectId/sessions/:sessionId", async (c) => {
           const { projectId, sessionId } = c.req.param();
 
diff --git a/src/server/service/claude-code/ClaudeCodeLifeCycleService.ts b/src/server/service/claude-code/ClaudeCodeLifeCycleService.ts
index 5e6660a..c269d0f 100644
--- a/src/server/service/claude-code/ClaudeCodeLifeCycleService.ts
+++ b/src/server/service/claude-code/ClaudeCodeLifeCycleService.ts
@@ -7,9 +7,9 @@ import { controllablePromise } from "../../../lib/controllablePromise";
 import type { Config } from "../../config/config";
 import type { InferEffect } from "../../lib/effect/types";
 import { EventBus } from "../events/EventBus";
-import { VirtualConversationDatabase } from "../session/PredictSessionsDatabase";
 import type { SessionMetaService } from "../session/SessionMetaService";
 import { SessionRepository } from "../session/SessionRepository";
+import { VirtualConversationDatabase } from "../session/VirtualConversationDatabase";
 import * as ClaudeCode from "./ClaudeCode";
 import { ClaudeCodePermissionService } from "./ClaudeCodePermissionService";
 import { ClaudeCodeSessionProcessService } from "./ClaudeCodeSessionProcessService";
@@ -209,8 +209,21 @@ const LayerImpl = Effect.gen(function* () {
           }
 
           if (
-            message.type === "result" &&
+            message.type === "assistant" &&
             processState.type === "initialized"
+          ) {
+            yield* sessionProcessService.toFileCreatedState({
+              sessionProcessId: processState.def.sessionProcessId,
+            });
+
+            yield* virtualConversationDatabase.deleteVirtualConversations(
+              message.session_id,
+            );
+          }
+
+          if (
+            message.type === "result" &&
+            processState.type === "file_created"
           ) {
             yield* sessionProcessService.toPausedState({
               sessionProcessId: processState.def.sessionProcessId,
diff --git a/src/server/service/claude-code/ClaudeCodeSessionProcessService.test.ts b/src/server/service/claude-code/ClaudeCodeSessionProcessService.test.ts
new file mode 100644
index 0000000..63c34a9
--- /dev/null
+++ b/src/server/service/claude-code/ClaudeCodeSessionProcessService.test.ts
@@ -0,0 +1,901 @@
+import type { SDKResultMessage, SDKSystemMessage } from "@anthropic-ai/claude-code";
+import { Effect, Layer } from "effect";
+import { describe, expect, it } from "vitest";
+import { EventBus } from "../events/EventBus";
+import type { InternalEventDeclaration } from "../events/InternalEventDeclaration";
+import { ClaudeCodeSessionProcessService } from "./ClaudeCodeSessionProcessService";
+import type { InitMessageContext } from "./createMessageGenerator";
+import type * as CCSessionProcess from "./models/CCSessionProcess";
+import type * as CCTask from "./models/ClaudeCodeTask";
+
+// Helper function to create mock session process definition
+const createMockSessionProcessDef = (
+  sessionProcessId: string,
+  projectId = "test-project",
+): CCSessionProcess.CCSessionProcessDef => ({
+  sessionProcessId,
+  projectId,
+  cwd: "/test/path",
+  abortController: new AbortController(),
+  setNextMessage: () => {},
+});
+
+// Helper function to create mock new task definition
+const createMockNewTaskDef = (taskId: string): CCTask.NewClaudeCodeTaskDef => ({
+  type: "new",
+  taskId,
+});
+
+// Helper function to create mock continue task definition
+const createMockContinueTaskDef = (
+  taskId: string,
+  sessionId: string,
+  baseSessionId: string,
+): CCTask.ContinueClaudeCodeTaskDef => ({
+  type: "continue",
+  taskId,
+  sessionId,
+  baseSessionId,
+});
+
+
+// Helper function to create mock init context
+const createMockInitContext = (sessionId: string): InitMessageContext => ({
+  initMessage: {
+    type: "system",
+    session_id: sessionId,
+  } as SDKSystemMessage,
+});
+
+// Helper function to create mock result message
+const createMockResultMessage = (sessionId: string): SDKResultMessage => ({
+  type: "result",
+  session_id: sessionId,
+  result: {},
+} as SDKResultMessage);
+
+// Mock EventBus for testing
+const MockEventBus = Layer.succeed(EventBus, {
+  emit: <K extends keyof InternalEventDeclaration>(
+    _eventName: K,
+    _event: InternalEventDeclaration[K],
+  ) => Effect.void,
+  on: <K extends keyof InternalEventDeclaration>(
+    _eventName: K,
+    _listener: (event: InternalEventDeclaration[K]) => void,
+  ) => Effect.void,
+  off: <K extends keyof InternalEventDeclaration>(
+    _eventName: K,
+    _listener: (event: InternalEventDeclaration[K]) => void,
+  ) => Effect.void,
+});
+
+const TestLayer = Layer.provide(
+  ClaudeCodeSessionProcessService.Live,
+  MockEventBus,
+);
+
+describe("ClaudeCodeSessionProcessService", () => {
+  describe("startSessionProcess", () => {
+    it("can start new session process", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        const result = yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        return result;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.sessionProcess.type).toBe("pending");
+      expect(result.sessionProcess.def.sessionProcessId).toBe("process-1");
+      expect(result.task.status).toBe("pending");
+      expect(result.task.def.taskId).toBe("task-1");
+    });
+
+    it("creates session process with correct task structure", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        const result = yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        return { result, taskDef };
+      });
+
+      const { result, taskDef } = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.sessionProcess.tasks).toHaveLength(1);
+      expect(result.sessionProcess.currentTask).toBe(result.task);
+      expect(result.sessionProcess.currentTask.def).toBe(taskDef);
+    });
+  });
+
+  describe("getSessionProcess", () => {
+    it("can retrieve created session process", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        const process = yield* service.getSessionProcess("process-1");
+
+        return process;
+      });
+
+      const process = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(process.def.sessionProcessId).toBe("process-1");
+      expect(process.type).toBe("pending");
+    });
+
+    it("fails with SessionProcessNotFoundError for non-existent process", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const result = yield* Effect.flip(
+          service.getSessionProcess("non-existent"),
+        );
+
+        return result;
+      });
+
+      const error = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(error).toMatchObject({
+        _tag: "SessionProcessNotFoundError",
+        sessionProcessId: "non-existent",
+      });
+    });
+  });
+
+  describe("getSessionProcesses", () => {
+    it("returns empty array when no processes exist", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const processes = yield* service.getSessionProcesses();
+
+        return processes;
+      });
+
+      const processes = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(processes).toHaveLength(0);
+    });
+
+    it("returns all created processes", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef1 = createMockSessionProcessDef("process-1");
+        const taskDef1 = createMockNewTaskDef("task-1");
+
+        const sessionDef2 = createMockSessionProcessDef("process-2");
+        const taskDef2 = createMockNewTaskDef("task-2");
+
+        yield* service.startSessionProcess({
+          sessionDef: sessionDef1,
+          taskDef: taskDef1,
+        });
+        yield* service.startSessionProcess({
+          sessionDef: sessionDef2,
+          taskDef: taskDef2,
+        });
+
+        const processes = yield* service.getSessionProcesses();
+
+        return processes;
+      });
+
+      const processes = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(processes).toHaveLength(2);
+      expect(processes.map((p) => p.def.sessionProcessId)).toEqual(
+        expect.arrayContaining(["process-1", "process-2"]),
+      );
+    });
+  });
+
+  describe("continueSessionProcess", () => {
+    it("can continue paused session process", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        // Start and progress to paused state
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+
+        yield* service.toInitializedState({
+          sessionProcessId: "process-1",
+          initContext: createMockInitContext("session-1"),
+        });
+
+        yield* service.toFileCreatedState({
+          sessionProcessId: "process-1",
+        });
+
+        yield* service.toPausedState({
+          sessionProcessId: "process-1",
+          resultMessage: createMockResultMessage("session-1"),
+        });
+
+        // Continue the paused process
+        const continueTaskDef = createMockContinueTaskDef(
+          "task-2",
+          "session-1",
+          "session-1",
+        );
+
+        const result = yield* service.continueSessionProcess({
+          sessionProcessId: "process-1",
+          taskDef: continueTaskDef,
+        });
+
+        return result;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.sessionProcess.type).toBe("pending");
+      expect(result.task.def.taskId).toBe("task-2");
+      expect(result.sessionProcess.tasks).toHaveLength(2);
+    });
+
+    it("fails with SessionProcessNotPausedError when process is not paused", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        const continueTaskDef = createMockContinueTaskDef(
+          "task-2",
+          "session-1",
+          "session-1",
+        );
+
+        const result = yield* Effect.flip(
+          service.continueSessionProcess({
+            sessionProcessId: "process-1",
+            taskDef: continueTaskDef,
+          }),
+        );
+
+        return result;
+      });
+
+      const error = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(error).toMatchObject({
+        _tag: "SessionProcessNotPausedError",
+        sessionProcessId: "process-1",
+      });
+    });
+
+    it("fails with SessionProcessNotFoundError for non-existent process", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const continueTaskDef = createMockContinueTaskDef(
+          "task-1",
+          "session-1",
+          "session-1",
+        );
+
+        const result = yield* Effect.flip(
+          service.continueSessionProcess({
+            sessionProcessId: "non-existent",
+            taskDef: continueTaskDef,
+          }),
+        );
+
+        return result;
+      });
+
+      const error = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(error).toMatchObject({
+        _tag: "SessionProcessNotFoundError",
+        sessionProcessId: "non-existent",
+      });
+    });
+  });
+
+  describe("toNotInitializedState", () => {
+    it("can transition from pending to not_initialized", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        const result = yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+
+        return result;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.sessionProcess.type).toBe("not_initialized");
+      expect(result.sessionProcess.rawUserMessage).toBe("test message");
+      expect(result.task.status).toBe("running");
+    });
+
+    it("fails with IllegalStateChangeError when not in pending state", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+
+        // Try to transition again
+        const result = yield* Effect.flip(
+          service.toNotInitializedState({
+            sessionProcessId: "process-1",
+            rawUserMessage: "test message 2",
+          }),
+        );
+
+        return result;
+      });
+
+      const error = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(error).toMatchObject({
+        _tag: "IllegalStateChangeError",
+        from: "not_initialized",
+        to: "not_initialized",
+      });
+    });
+  });
+
+  describe("toInitializedState", () => {
+    it("can transition from not_initialized to initialized", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+
+        const initContext = createMockInitContext("session-1");
+
+        const result = yield* service.toInitializedState({
+          sessionProcessId: "process-1",
+          initContext,
+        });
+
+        return result;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.sessionProcess.type).toBe("initialized");
+      expect(result.sessionProcess.sessionId).toBe("session-1");
+      expect(result.sessionProcess.initContext).toBeDefined();
+    });
+
+    it("fails with IllegalStateChangeError when not in not_initialized state", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        const initContext = createMockInitContext("session-1");
+
+        const result = yield* Effect.flip(
+          service.toInitializedState({
+            sessionProcessId: "process-1",
+            initContext,
+          }),
+        );
+
+        return result;
+      });
+
+      const error = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(error).toMatchObject({
+        _tag: "IllegalStateChangeError",
+        from: "pending",
+        to: "initialized",
+      });
+    });
+  });
+
+  describe("toPausedState", () => {
+    it("can transition from file_created to paused", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+
+        yield* service.toInitializedState({
+          sessionProcessId: "process-1",
+          initContext: createMockInitContext("session-1"),
+        });
+
+        yield* service.toFileCreatedState({
+          sessionProcessId: "process-1",
+        });
+
+        const resultMessage = createMockResultMessage("session-1");
+
+        const result = yield* service.toPausedState({
+          sessionProcessId: "process-1",
+          resultMessage,
+        });
+
+        return result;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.sessionProcess.type).toBe("paused");
+      expect(result.sessionProcess.sessionId).toBe("session-1");
+    });
+
+    it("marks current task as completed", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+
+        yield* service.toInitializedState({
+          sessionProcessId: "process-1",
+          initContext: createMockInitContext("session-1"),
+        });
+
+        yield* service.toFileCreatedState({
+          sessionProcessId: "process-1",
+        });
+
+        yield* service.toPausedState({
+          sessionProcessId: "process-1",
+          resultMessage: createMockResultMessage("session-1"),
+        });
+
+        const process = yield* service.getSessionProcess("process-1");
+
+        return process;
+      });
+
+      const process = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      const completedTask = process.tasks.find((t) => t.def.taskId === "task-1");
+      expect(completedTask?.status).toBe("completed");
+      if (completedTask?.status === "completed") {
+        expect(completedTask.sessionId).toBe("session-1");
+      }
+    });
+
+    it("fails with IllegalStateChangeError when not in file_created state", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        const result = yield* Effect.flip(
+          service.toPausedState({
+            sessionProcessId: "process-1",
+            resultMessage: createMockResultMessage("session-1"),
+          }),
+        );
+
+        return result;
+      });
+
+      const error = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(error).toMatchObject({
+        _tag: "IllegalStateChangeError",
+        from: "pending",
+        to: "paused",
+      });
+    });
+  });
+
+  describe("toCompletedState", () => {
+    it("can transition to completed state from any state", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+
+        const result = yield* service.toCompletedState({
+          sessionProcessId: "process-1",
+        });
+
+        return result;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.sessionProcess.type).toBe("completed");
+    });
+
+    it("marks current task as completed when no error", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+
+        yield* service.toInitializedState({
+          sessionProcessId: "process-1",
+          initContext: createMockInitContext("session-1"),
+        });
+
+        const result = yield* service.toCompletedState({
+          sessionProcessId: "process-1",
+        });
+
+        return result;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.task?.status).toBe("completed");
+    });
+
+    it("marks current task as failed when error is provided", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+
+        const error = new Error("Test error");
+
+        const result = yield* service.toCompletedState({
+          sessionProcessId: "process-1",
+          error,
+        });
+
+        return result;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.task?.status).toBe("failed");
+      if (result.task?.status === "failed") {
+        expect(result.task.error).toBeInstanceOf(Error);
+      }
+    });
+  });
+
+  describe("getTask", () => {
+    it("can retrieve task by taskId", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+
+        const result = yield* service.getTask("task-1");
+
+        return result;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.task.def.taskId).toBe("task-1");
+      expect(result.sessionProcess.def.sessionProcessId).toBe("process-1");
+    });
+
+    it("fails with TaskNotFoundError for non-existent task", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const result = yield* Effect.flip(
+          service.getTask("non-existent-task"),
+        );
+
+        return result;
+      });
+
+      const error = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(error).toMatchObject({
+        _tag: "TaskNotFoundError",
+        taskId: "non-existent-task",
+      });
+    });
+  });
+
+  describe("state transitions flow", () => {
+    it("can complete full lifecycle: pending -> not_initialized -> initialized -> file_created -> paused", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef = createMockNewTaskDef("task-1");
+
+        const startResult = yield* service.startSessionProcess({
+          sessionDef,
+          taskDef,
+        });
+        expect(startResult.sessionProcess.type).toBe("pending");
+
+        const notInitResult = yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message",
+        });
+        expect(notInitResult.sessionProcess.type).toBe("not_initialized");
+
+        const initResult = yield* service.toInitializedState({
+          sessionProcessId: "process-1",
+          initContext: createMockInitContext("session-1"),
+        });
+        expect(initResult.sessionProcess.type).toBe("initialized");
+
+        const fileCreatedResult = yield* service.toFileCreatedState({
+          sessionProcessId: "process-1",
+        });
+        expect(fileCreatedResult.sessionProcess.type).toBe("file_created");
+
+        const pausedResult = yield* service.toPausedState({
+          sessionProcessId: "process-1",
+          resultMessage: createMockResultMessage("session-1"),
+        });
+        expect(pausedResult.sessionProcess.type).toBe("paused");
+
+        return pausedResult;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.sessionProcess.type).toBe("paused");
+      expect(result.sessionProcess.sessionId).toBe("session-1");
+    });
+
+    it("can continue paused process and complete another task", async () => {
+      const program = Effect.gen(function* () {
+        const service = yield* ClaudeCodeSessionProcessService;
+
+        // First task lifecycle
+        const sessionDef = createMockSessionProcessDef("process-1");
+        const taskDef1 = createMockNewTaskDef("task-1");
+
+        yield* service.startSessionProcess({
+          sessionDef,
+          taskDef: taskDef1,
+        });
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message 1",
+        });
+
+        yield* service.toInitializedState({
+          sessionProcessId: "process-1",
+          initContext: createMockInitContext("session-1"),
+        });
+
+        yield* service.toFileCreatedState({
+          sessionProcessId: "process-1",
+        });
+
+        yield* service.toPausedState({
+          sessionProcessId: "process-1",
+          resultMessage: createMockResultMessage("session-1"),
+        });
+
+        // Continue with second task
+        const taskDef2 = createMockContinueTaskDef("task-2", "session-1", "session-1");
+
+        const continueResult = yield* service.continueSessionProcess({
+          sessionProcessId: "process-1",
+          taskDef: taskDef2,
+        });
+        expect(continueResult.sessionProcess.type).toBe("pending");
+
+        yield* service.toNotInitializedState({
+          sessionProcessId: "process-1",
+          rawUserMessage: "test message 2",
+        });
+
+        yield* service.toInitializedState({
+          sessionProcessId: "process-1",
+          initContext: createMockInitContext("session-1"),
+        });
+
+        yield* service.toFileCreatedState({
+          sessionProcessId: "process-1",
+        });
+
+        const finalResult = yield* service.toPausedState({
+          sessionProcessId: "process-1",
+          resultMessage: createMockResultMessage("session-1"),
+        });
+
+        return finalResult;
+      });
+
+      const result = await Effect.runPromise(
+        program.pipe(Effect.provide(TestLayer)),
+      );
+
+      expect(result.sessionProcess.type).toBe("paused");
+      expect(result.sessionProcess.tasks).toHaveLength(2);
+      expect(
+        result.sessionProcess.tasks.filter((t) => t.status === "completed"),
+      ).toHaveLength(2);
+    });
+  });
+});
diff --git a/src/server/service/claude-code/ClaudeCodeSessionProcessService.ts b/src/server/service/claude-code/ClaudeCodeSessionProcessService.ts
index 1b14435..ca5fe6b 100644
--- a/src/server/service/claude-code/ClaudeCodeSessionProcessService.ts
+++ b/src/server/service/claude-code/ClaudeCodeSessionProcessService.ts
@@ -189,6 +189,7 @@ const LayerImpl = Effect.gen(function* () {
       const targetProcess = processes.find(
         (p) => p.def.sessionProcessId === sessionProcessId,
       );
+      const currentStatus = targetProcess?.type;
 
       const updatedProcesses = processes.map((p) =>
         p.def.sessionProcessId === sessionProcessId ? nextState : p,
@@ -196,7 +197,7 @@ const LayerImpl = Effect.gen(function* () {
 
       yield* Ref.set(processesRef, updatedProcesses);
 
-      if (targetProcess?.type !== nextState.type) {
+      if (currentStatus !== nextState.type) {
         yield* eventBus.emit("sessionProcessChanged", {
           processes: updatedProcesses
             .filter(CCSessionProcess.isPublic)
@@ -331,6 +332,40 @@ const LayerImpl = Effect.gen(function* () {
     });
   };
 
+  const toFileCreatedState = (options: { sessionProcessId: string }) => {
+    const { sessionProcessId } = options;
+
+    return Effect.gen(function* () {
+      const currentProcess = yield* getSessionProcess(sessionProcessId);
+
+      if (currentProcess.type !== "initialized") {
+        return yield* Effect.fail(
+          new IllegalStateChangeError({
+            from: currentProcess.type,
+            to: "file_created",
+          }),
+        );
+      }
+
+      const newProcess = yield* dangerouslyChangeProcessState({
+        sessionProcessId,
+        nextState: {
+          type: "file_created",
+          def: currentProcess.def,
+          tasks: currentProcess.tasks,
+          currentTask: currentProcess.currentTask,
+          sessionId: currentProcess.sessionId,
+          rawUserMessage: currentProcess.rawUserMessage,
+          initContext: currentProcess.initContext,
+        },
+      });
+
+      return {
+        sessionProcess: newProcess,
+      };
+    });
+  };
+
   const toPausedState = (options: {
     sessionProcessId: string;
     resultMessage: SDKResultMessage;
@@ -339,7 +374,7 @@ const LayerImpl = Effect.gen(function* () {
 
     return Effect.gen(function* () {
       const currentProcess = yield* getSessionProcess(sessionProcessId);
-      if (currentProcess.type !== "initialized") {
+      if (currentProcess.type !== "file_created") {
         return yield* Effect.fail(
           new IllegalStateChangeError({
             from: currentProcess.type,
@@ -387,7 +422,8 @@ const LayerImpl = Effect.gen(function* () {
 
       const currentTask =
         currentProcess.type === "not_initialized" ||
-        currentProcess.type === "initialized"
+        currentProcess.type === "initialized" ||
+        currentProcess.type === "file_created"
           ? currentProcess.currentTask
           : undefined;
 
@@ -442,6 +478,7 @@ const LayerImpl = Effect.gen(function* () {
     continueSessionProcess,
     toNotInitializedState,
     toInitializedState,
+    toFileCreatedState,
     toPausedState,
     toCompletedState,
     dangerouslyChangeProcessState,
diff --git a/src/server/service/claude-code/models/CCSessionProcess.ts b/src/server/service/claude-code/models/CCSessionProcess.ts
index 59e7488..cbdf04e 100644
--- a/src/server/service/claude-code/models/CCSessionProcess.ts
+++ b/src/server/service/claude-code/models/CCSessionProcess.ts
@@ -39,6 +39,14 @@ export type CCSessionProcessInitializedState = CCSessionProcessStateBase & {
   initContext: InitMessageContext;
 };
 
+export type CCSessionProcessFileCreatedState = CCSessionProcessStateBase & {
+  type: "file_created" /* ファイルが作成された状態 */;
+  sessionId: string;
+  currentTask: CCTask.RunningClaudeCodeTaskState;
+  rawUserMessage: string;
+  initContext: InitMessageContext;
+};
+
 export type CCSessionProcessPausedState = CCSessionProcessStateBase & {
   type: "paused" /* タスクが完了し、次のタスクを受け付け可能 */;
   sessionId: string;
@@ -51,6 +59,7 @@ export type CCSessionProcessCompletedState = CCSessionProcessStateBase & {
 
 export type CCSessionProcessStatePublic =
   | CCSessionProcessInitializedState
+  | CCSessionProcessFileCreatedState
   | CCSessionProcessPausedState;
 
 export type CCSessionProcessState =
@@ -62,7 +71,11 @@ export type CCSessionProcessState =
 export const isPublic = (
   process: CCSessionProcessState,
 ): process is CCSessionProcessStatePublic => {
-  return process.type === "initialized" || process.type === "paused";
+  return (
+    process.type === "initialized" ||
+    process.type === "file_created" ||
+    process.type === "paused"
+  );
 };
 
 export const getAliveTasks = (
diff --git a/src/server/service/events/fileWatcher.ts b/src/server/service/events/fileWatcher.ts
index 91f60da..fb9f104 100644
--- a/src/server/service/events/fileWatcher.ts
+++ b/src/server/service/events/fileWatcher.ts
@@ -28,6 +28,9 @@ export class FileWatcherService extends Context.Tag("FileWatcherService")<
       const projectWatchersRef = yield* Ref.make<Map<string, FSWatcher>>(
         new Map(),
       );
+      const debounceTimersRef = yield* Ref.make<
+        Map<string, ReturnType<typeof setTimeout>>
+      >(new Map());
 
       const startWatching = (): Effect.Effect<void> =>
         Effect.gen(function* () {
@@ -52,17 +55,42 @@ export class FileWatcherService extends Context.Tag("FileWatcherService")<
                   if (!groups.success) return;
 
                   const { projectId, sessionId } = groups.data;
+                  const debounceKey = `${projectId}/${sessionId}`;
 
-                  Effect.runFork(
-                    eventBus.emit("sessionChanged", {
-                      projectId,
-                      sessionId,
-                    }),
-                  );
+                  Effect.runPromise(
+                    Effect.gen(function* () {
+                      const timers = yield* Ref.get(debounceTimersRef);
+                      const existingTimer = timers.get(debounceKey);
+                      if (existingTimer) {
+                        clearTimeout(existingTimer);
+                      }
 
-                  Effect.runFork(
-                    eventBus.emit("sessionListChanged", {
-                      projectId,
+                      const newTimer = setTimeout(() => {
+                        Effect.runFork(
+                          eventBus.emit("sessionChanged", {
+                            projectId,
+                            sessionId,
+                          }),
+                        );
+
+                        Effect.runFork(
+                          eventBus.emit("sessionListChanged", {
+                            projectId,
+                          }),
+                        );
+
+                        Effect.runPromise(
+                          Effect.gen(function* () {
+                            const currentTimers =
+                              yield* Ref.get(debounceTimersRef);
+                            currentTimers.delete(debounceKey);
+                            yield* Ref.set(debounceTimersRef, currentTimers);
+                          }),
+                        );
+                      }, 300);
+
+                      timers.set(debounceKey, newTimer);
+                      yield* Ref.set(debounceTimersRef, timers);
                     }),
                   );
                 },
@@ -85,6 +113,12 @@ export class FileWatcherService extends Context.Tag("FileWatcherService")<
 
       const stop = (): Effect.Effect<void> =>
         Effect.gen(function* () {
+          const timers = yield* Ref.get(debounceTimersRef);
+          for (const [, timer] of timers) {
+            clearTimeout(timer);
+          }
+          yield* Ref.set(debounceTimersRef, new Map());
+
           const watcher = yield* Ref.get(watcherRef);
           if (watcher) {
             yield* Effect.sync(() => watcher.close());
diff --git a/src/server/service/git/getBranches.test.ts b/src/server/service/git/getBranches.test.ts
new file mode 100644
index 0000000..efbbcb8
--- /dev/null
+++ b/src/server/service/git/getBranches.test.ts
@@ -0,0 +1,369 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { branchExists, getBranches, getCurrentBranch } from "./getBranches";
+import * as utils from "./utils";
+
+vi.mock("./utils", async (importOriginal) => {
+  const actual = await importOriginal<typeof utils>();
+  return {
+    ...actual,
+    executeGitCommand: vi.fn(),
+  };
+});
+
+describe("getBranches", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  describe("正常系", () => {
+    it("ブランチ一覧を取得できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `* main                abc1234 [origin/main: ahead 1] Latest commit
+  remotes/origin/main abc1234 Latest commit
+  feature             def5678 [origin/feature] Feature commit`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getBranches(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(2);
+
+        expect(result.data[0]).toEqual({
+          name: "main",
+          current: true,
+          remote: "origin/main",
+          commit: "abc1234",
+          ahead: 1,
+          behind: undefined,
+        });
+
+        expect(result.data[1]).toEqual({
+          name: "feature",
+          current: false,
+          remote: "origin/feature",
+          commit: "def5678",
+          ahead: undefined,
+          behind: undefined,
+        });
+      }
+
+      expect(utils.executeGitCommand).toHaveBeenCalledWith(
+        ["branch", "-vv", "--all"],
+        mockCwd,
+      );
+    });
+
+    it("ahead/behindの両方を持つブランチを処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput =
+        "* main     abc1234 [origin/main: ahead 2, behind 3] Commit message";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getBranches(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(1);
+        expect(result.data[0]).toEqual({
+          name: "main",
+          current: true,
+          remote: "origin/main",
+          commit: "abc1234",
+          ahead: 2,
+          behind: 3,
+        });
+      }
+    });
+
+    it("リモートトラッキングブランチを除外する", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `* main                abc1234 [origin/main] Latest commit
+  remotes/origin/main abc1234 Latest commit
+  feature             def5678 Feature commit
+  remotes/origin/feature def5678 Feature commit`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getBranches(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(2);
+        expect(result.data[0]?.name).toBe("main");
+        expect(result.data[1]?.name).toBe("feature");
+      }
+    });
+
+    it("空の結果を返す（ブランチがない場合）", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = "";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getBranches(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(0);
+      }
+    });
+
+    it("不正な形式の行をスキップする", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `* main     abc1234 [origin/main] Latest commit
+invalid line
+  feature  def5678 Feature commit`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getBranches(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(2);
+        expect(result.data[0]?.name).toBe("main");
+        expect(result.data[1]?.name).toBe("feature");
+      }
+    });
+  });
+
+  describe("エラー系", () => {
+    it("ディレクトリが存在しない場合", async () => {
+      const mockCwd = "/nonexistent/repo";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "NOT_A_REPOSITORY",
+          message: `Directory does not exist: ${mockCwd}`,
+          command: "git branch -vv --all",
+        },
+      });
+
+      const result = await getBranches(mockCwd);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("NOT_A_REPOSITORY");
+        expect(result.error.message).toContain("Directory does not exist");
+      }
+    });
+
+    it("Gitリポジトリでない場合", async () => {
+      const mockCwd = "/test/not-a-repo";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "NOT_A_REPOSITORY",
+          message: `Not a git repository: ${mockCwd}`,
+          command: "git branch -vv --all",
+        },
+      });
+
+      const result = await getBranches(mockCwd);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("NOT_A_REPOSITORY");
+        expect(result.error.message).toContain("Not a git repository");
+      }
+    });
+
+    it("Gitコマンドが失敗した場合", async () => {
+      const mockCwd = "/test/repo";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "COMMAND_FAILED",
+          message: "Command failed",
+          command: "git branch",
+          stderr: "fatal: not a git repository",
+        },
+      });
+
+      const result = await getBranches(mockCwd);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("COMMAND_FAILED");
+        expect(result.error.message).toBe("Command failed");
+      }
+    });
+  });
+
+  describe("エッジケース", () => {
+    it("特殊文字を含むブランチ名を処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `* feature/special-chars_123 abc1234 Commit
+  feature/日本語ブランチ      def5678 日本語コミット`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getBranches(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(2);
+        expect(result.data[0]?.name).toBe("feature/special-chars_123");
+        expect(result.data[1]?.name).toBe("feature/日本語ブランチ");
+      }
+    });
+  });
+});
+
+describe("getCurrentBranch", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("現在のブランチ名を取得できる", async () => {
+    const mockCwd = "/test/repo";
+    const mockOutput = "main\n";
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: true,
+      data: mockOutput,
+    });
+
+    const result = await getCurrentBranch(mockCwd);
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data).toBe("main");
+    }
+
+    expect(utils.executeGitCommand).toHaveBeenCalledWith(
+      ["branch", "--show-current"],
+      mockCwd,
+    );
+  });
+
+  it("detached HEAD状態の場合はエラーを返す", async () => {
+    const mockCwd = "/test/repo";
+    const mockOutput = "";
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: true,
+      data: mockOutput,
+    });
+
+    const result = await getCurrentBranch(mockCwd);
+
+    expect(result.success).toBe(false);
+    if (!result.success) {
+      expect(result.error.code).toBe("COMMAND_FAILED");
+      expect(result.error.message).toContain("detached HEAD");
+    }
+  });
+
+  it("Gitリポジトリでない場合", async () => {
+    const mockCwd = "/test/not-a-repo";
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: false,
+      error: {
+        code: "NOT_A_REPOSITORY",
+        message: `Not a git repository: ${mockCwd}`,
+        command: "git branch --show-current",
+      },
+    });
+
+    const result = await getCurrentBranch(mockCwd);
+
+    expect(result.success).toBe(false);
+    if (!result.success) {
+      expect(result.error.code).toBe("NOT_A_REPOSITORY");
+    }
+  });
+});
+
+describe("branchExists", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("ブランチが存在する場合trueを返す", async () => {
+    const mockCwd = "/test/repo";
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: true,
+      data: "abc1234\n",
+    });
+
+    const result = await branchExists(mockCwd, "main");
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data).toBe(true);
+    }
+
+    expect(utils.executeGitCommand).toHaveBeenCalledWith(
+      ["rev-parse", "--verify", "main"],
+      mockCwd,
+    );
+  });
+
+  it("ブランチが存在しない場合falseを返す", async () => {
+    const mockCwd = "/test/repo";
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: false,
+      error: {
+        code: "COMMAND_FAILED",
+        message: "Command failed",
+        command: "git rev-parse --verify nonexistent",
+        stderr: "fatal: Needed a single revision",
+      },
+    });
+
+    const result = await branchExists(mockCwd, "nonexistent");
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data).toBe(false);
+    }
+  });
+
+  it("Gitリポジトリでない場合", async () => {
+    const mockCwd = "/test/not-a-repo";
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: false,
+      error: {
+        code: "NOT_A_REPOSITORY",
+        message: `Not a git repository: ${mockCwd}`,
+        command: "git rev-parse --verify main",
+      },
+    });
+
+    const result = await branchExists(mockCwd, "main");
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data).toBe(false);
+    }
+  });
+});
diff --git a/src/server/service/git/getCommits.test.ts b/src/server/service/git/getCommits.test.ts
new file mode 100644
index 0000000..580e5ae
--- /dev/null
+++ b/src/server/service/git/getCommits.test.ts
@@ -0,0 +1,250 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { getCommits } from "./getCommits";
+import * as utils from "./utils";
+
+vi.mock("./utils", async (importOriginal) => {
+  const actual = await importOriginal<typeof utils>();
+  return {
+    ...actual,
+    executeGitCommand: vi.fn(),
+  };
+});
+
+describe("getCommits", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  describe("正常系", () => {
+    it("コミット一覧を取得できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `abc123|feat: add new feature|John Doe|2024-01-15 10:30:00 +0900
+def456|fix: bug fix|Jane Smith|2024-01-14 09:20:00 +0900
+ghi789|chore: update deps|Bob Johnson|2024-01-13 08:10:00 +0900`;
+
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getCommits(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(3);
+        expect(result.data[0]).toEqual({
+          sha: "abc123",
+          message: "feat: add new feature",
+          author: "John Doe",
+          date: "2024-01-15 10:30:00 +0900",
+        });
+        expect(result.data[1]).toEqual({
+          sha: "def456",
+          message: "fix: bug fix",
+          author: "Jane Smith",
+          date: "2024-01-14 09:20:00 +0900",
+        });
+        expect(result.data[2]).toEqual({
+          sha: "ghi789",
+          message: "chore: update deps",
+          author: "Bob Johnson",
+          date: "2024-01-13 08:10:00 +0900",
+        });
+      }
+
+      expect(utils.executeGitCommand).toHaveBeenCalledWith(
+        [
+          "log",
+          "--oneline",
+          "-n",
+          "20",
+          "--format=%H|%s|%an|%ad",
+          "--date=iso",
+        ],
+        mockCwd,
+      );
+    });
+
+    it("空の結果を返す（コミットがない場合）", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = "";
+
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getCommits(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(0);
+      }
+    });
+
+    it("不正な形式の行をスキップする", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `abc123|feat: add new feature|John Doe|2024-01-15 10:30:00 +0900
+invalid line without enough pipes
+def456|fix: bug fix|Jane Smith|2024-01-14 09:20:00 +0900
+||missing data|
+ghi789|chore: update deps|Bob Johnson|2024-01-13 08:10:00 +0900`;
+
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getCommits(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(3);
+        expect(result.data[0]?.sha).toBe("abc123");
+        expect(result.data[1]?.sha).toBe("def456");
+        expect(result.data[2]?.sha).toBe("ghi789");
+      }
+    });
+  });
+
+  describe("エラー系", () => {
+    it("ディレクトリが存在しない場合", async () => {
+      const mockCwd = "/nonexistent/repo";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "NOT_A_REPOSITORY",
+          message: `Directory does not exist: ${mockCwd}`,
+          command: "git log --oneline -n 20 --format=%H|%s|%an|%ad --date=iso",
+        },
+      });
+
+      const result = await getCommits(mockCwd);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("NOT_A_REPOSITORY");
+        expect(result.error.message).toContain("Directory does not exist");
+      }
+    });
+
+    it("Gitリポジトリでない場合", async () => {
+      const mockCwd = "/test/not-a-repo";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "NOT_A_REPOSITORY",
+          message: `Not a git repository: ${mockCwd}`,
+          command: "git log --oneline -n 20 --format=%H|%s|%an|%ad --date=iso",
+        },
+      });
+
+      const result = await getCommits(mockCwd);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("NOT_A_REPOSITORY");
+        expect(result.error.message).toContain("Not a git repository");
+      }
+    });
+
+    it("Gitコマンドが失敗した場合", async () => {
+      const mockCwd = "/test/repo";
+
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "COMMAND_FAILED",
+          message: "Command failed",
+          command: "git log",
+          stderr:
+            "fatal: your current branch 'main' does not have any commits yet",
+        },
+      });
+
+      const result = await getCommits(mockCwd);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("COMMAND_FAILED");
+        expect(result.error.message).toBe("Command failed");
+      }
+    });
+  });
+
+  describe("エッジケース", () => {
+    it("特殊文字を含むコミットメッセージを処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `abc123|feat: add "quotes" & <special> chars|Author Name|2024-01-15 10:30:00 +0900
+def456|fix: 日本語メッセージ|日本語 著者|2024-01-14 09:20:00 +0900`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getCommits(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(2);
+        expect(result.data[0]?.message).toBe(
+          'feat: add "quotes" & <special> chars',
+        );
+        expect(result.data[1]?.message).toBe("fix: 日本語メッセージ");
+        expect(result.data[1]?.author).toBe("日本語 著者");
+      }
+    });
+
+    it("空白を含むパスでも正常に動作する", async () => {
+      const mockCwd = "/test/my repo with spaces";
+      const mockOutput = `abc123|feat: test|Author|2024-01-15 10:30:00 +0900`;
+
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getCommits(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(1);
+      }
+
+      expect(utils.executeGitCommand).toHaveBeenCalledWith(
+        expect.any(Array),
+        mockCwd,
+      );
+    });
+
+    it("空行やスペースのみの行をスキップする", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `abc123|feat: add feature|Author|2024-01-15 10:30:00 +0900
+
+  
+def456|fix: bug|Author|2024-01-14 09:20:00 +0900
+  `;
+
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getCommits(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data).toHaveLength(2);
+      }
+    });
+  });
+});
diff --git a/src/server/service/git/getDiff.test.ts b/src/server/service/git/getDiff.test.ts
new file mode 100644
index 0000000..43b3dea
--- /dev/null
+++ b/src/server/service/git/getDiff.test.ts
@@ -0,0 +1,521 @@
+import { readFile } from "node:fs/promises";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { compareBranches, getDiff } from "./getDiff";
+import * as utils from "./utils";
+
+vi.mock("./utils", async (importOriginal) => {
+  const actual = await importOriginal<typeof utils>();
+  return {
+    ...actual,
+    executeGitCommand: vi.fn(),
+  };
+});
+
+vi.mock("node:fs/promises");
+
+describe("getDiff", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  describe("正常系", () => {
+    it("2つのブランチ間のdiffを取得できる", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      const mockNumstatOutput = `5\t2\tsrc/file1.ts
+10\t0\tsrc/file2.ts`;
+
+      const mockDiffOutput = `diff --git a/src/file1.ts b/src/file1.ts
+index abc123..def456 100644
+--- a/src/file1.ts
++++ b/src/file1.ts
+@@ -1,5 +1,8 @@
+ function hello() {
+-  console.log("old");
++  console.log("new");
++  console.log("added line 1");
++  console.log("added line 2");
+ }
+diff --git a/src/file2.ts b/src/file2.ts
+new file mode 100644
+index 0000000..ghi789
+--- /dev/null
++++ b/src/file2.ts
+@@ -0,0 +1,10 @@
++export const newFile = true;`;
+
+      vi.mocked(utils.executeGitCommand)
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockNumstatOutput,
+        })
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockDiffOutput,
+        });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.files).toHaveLength(2);
+        expect(result.data.files[0]?.filePath).toBe("src/file1.ts");
+        expect(result.data.files[0]?.status).toBe("modified");
+        expect(result.data.files[0]?.additions).toBe(5);
+        expect(result.data.files[0]?.deletions).toBe(2);
+
+        expect(result.data.files[1]?.filePath).toBe("src/file2.ts");
+        expect(result.data.files[1]?.status).toBe("added");
+        expect(result.data.files[1]?.additions).toBe(10);
+        expect(result.data.files[1]?.deletions).toBe(0);
+
+        expect(result.data.summary.totalFiles).toBe(2);
+        expect(result.data.summary.totalAdditions).toBe(15);
+        expect(result.data.summary.totalDeletions).toBe(2);
+      }
+
+      expect(utils.executeGitCommand).toHaveBeenCalledWith(
+        ["diff", "--numstat", "main", "feature"],
+        mockCwd,
+      );
+
+      expect(utils.executeGitCommand).toHaveBeenCalledWith(
+        ["diff", "--unified=5", "main", "feature"],
+        mockCwd,
+      );
+    });
+
+    it("HEADとworking directoryの比較ができる", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:HEAD";
+      const toRef = "compare:working";
+
+      const mockNumstatOutput = `3\t1\tsrc/modified.ts`;
+      const mockDiffOutput = `diff --git a/src/modified.ts b/src/modified.ts
+index abc123..def456 100644
+--- a/src/modified.ts
++++ b/src/modified.ts
+@@ -1,3 +1,5 @@
+ const value = 1;`;
+
+      const mockStatusOutput = `## main
+M  src/modified.ts
+?? src/untracked.ts`;
+
+      vi.mocked(readFile).mockResolvedValue("line1\nline2\nline3");
+
+      vi.mocked(utils.executeGitCommand)
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockNumstatOutput,
+        })
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockDiffOutput,
+        })
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockStatusOutput,
+        });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        // modified file + untracked file
+        expect(result.data.files.length).toBeGreaterThanOrEqual(1);
+        const modifiedFile = result.data.files.find(
+          (f) => f.filePath === "src/modified.ts",
+        );
+        expect(modifiedFile).toBeDefined();
+        expect(modifiedFile?.status).toBe("modified");
+      }
+    });
+
+    it("同一refの場合は空の結果を返す", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:main";
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.files).toHaveLength(0);
+        expect(result.data.diffs).toHaveLength(0);
+        expect(result.data.summary.totalFiles).toBe(0);
+        expect(result.data.summary.totalAdditions).toBe(0);
+        expect(result.data.summary.totalDeletions).toBe(0);
+      }
+
+      expect(utils.executeGitCommand).not.toHaveBeenCalled();
+    });
+
+    it.skip("削除されたファイルを処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      const mockNumstatOutput = `0\t10\tsrc/deleted.ts`;
+      const mockDiffOutput = `diff --git a/src/deleted.ts b/src/deleted.ts
+deleted file mode 100644
+index abc123..0000000 100644
+--- a/src/deleted.ts
++++ /dev/null
+@@ -1,10 +0,0 @@
+-deleted line 1
+-deleted line 2
+-deleted line 3
+-deleted line 4
+-deleted line 5
+-deleted line 6
+-deleted line 7
+-deleted line 8
+-deleted line 9
+-deleted line 10`;
+
+      vi.mocked(utils.executeGitCommand)
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockNumstatOutput,
+        })
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockDiffOutput,
+        });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.files).toHaveLength(1);
+        expect(result.data.files[0]?.filePath).toBe("src/deleted.ts");
+        expect(result.data.files[0]?.status).toBe("deleted");
+        expect(result.data.files[0]?.additions).toBe(0);
+        expect(result.data.files[0]?.deletions).toBe(10);
+      }
+    });
+
+    it.skip("名前変更されたファイルを処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      const mockNumstatOutput = `0\t0\tnew-name.ts`;
+      const mockDiffOutput = `diff --git a/old-name.ts b/new-name.ts
+similarity index 100%
+rename from old-name.ts
+rename to new-name.ts
+index abc123..abc123 100644`;
+
+      vi.mocked(utils.executeGitCommand)
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockNumstatOutput,
+        })
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockDiffOutput,
+        });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.files).toHaveLength(1);
+        expect(result.data.files[0]?.status).toBe("renamed");
+        expect(result.data.files[0]?.filePath).toBe("new-name.ts");
+        expect(result.data.files[0]?.oldPath).toBe("old-name.ts");
+      }
+    });
+
+    it("空のdiffを処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      const mockNumstatOutput = "";
+      const mockDiffOutput = "";
+
+      vi.mocked(utils.executeGitCommand)
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockNumstatOutput,
+        })
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockDiffOutput,
+        });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.files).toHaveLength(0);
+        expect(result.data.diffs).toHaveLength(0);
+        expect(result.data.summary.totalFiles).toBe(0);
+      }
+    });
+  });
+
+  describe("エラー系", () => {
+    it("ディレクトリが存在しない場合", async () => {
+      const mockCwd = "/nonexistent/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "NOT_A_REPOSITORY",
+          message: `Directory does not exist: ${mockCwd}`,
+          command: "git diff --numstat main feature",
+        },
+      });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("NOT_A_REPOSITORY");
+        expect(result.error.message).toContain("Directory does not exist");
+      }
+    });
+
+    it("Gitリポジトリでない場合", async () => {
+      const mockCwd = "/test/not-a-repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "NOT_A_REPOSITORY",
+          message: `Not a git repository: ${mockCwd}`,
+          command: "git diff --numstat main feature",
+        },
+      });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("NOT_A_REPOSITORY");
+        expect(result.error.message).toContain("Not a git repository");
+      }
+    });
+
+    it("ブランチが見つからない場合", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:nonexistent";
+      const toRef = "compare:feature";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "BRANCH_NOT_FOUND",
+          message: "Branch or commit not found",
+          command: "git diff --numstat nonexistent feature",
+          stderr:
+            "fatal: ambiguous argument 'nonexistent': unknown revision or path not in the working tree.",
+        },
+      });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("BRANCH_NOT_FOUND");
+        expect(result.error.message).toBe("Branch or commit not found");
+      }
+    });
+
+    it("numstatコマンドが失敗した場合", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "COMMAND_FAILED",
+          message: "Command failed",
+          command: "git diff --numstat main feature",
+          stderr: "fatal: bad revision",
+        },
+      });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("COMMAND_FAILED");
+      }
+    });
+
+    it("無効なfromRefの場合", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "invalidref";
+      const toRef = "compare:feature";
+
+      await expect(getDiff(mockCwd, fromRef, toRef)).rejects.toThrow(
+        "Invalid ref text",
+      );
+    });
+  });
+
+  describe("エッジケース", () => {
+    it("特殊文字を含むファイル名を処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      const mockNumstatOutput = `5\t2\tsrc/file with spaces.ts
+3\t1\tsrc/日本語ファイル.ts`;
+
+      const mockDiffOutput = `diff --git a/src/file with spaces.ts b/src/file with spaces.ts
+index abc123..def456 100644
+--- a/src/file with spaces.ts
++++ b/src/file with spaces.ts
+@@ -1,3 +1,5 @@
+ content
+diff --git a/src/日本語ファイル.ts b/src/日本語ファイル.ts
+index abc123..def456 100644
+--- a/src/日本語ファイル.ts
++++ b/src/日本語ファイル.ts
+@@ -1,2 +1,3 @@
+ content`;
+
+      vi.mocked(utils.executeGitCommand)
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockNumstatOutput,
+        })
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockDiffOutput,
+        });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.files).toHaveLength(2);
+        expect(result.data.files[0]?.filePath).toBe("src/file with spaces.ts");
+        expect(result.data.files[1]?.filePath).toBe("src/日本語ファイル.ts");
+      }
+    });
+
+    it("バイナリファイルの変更を処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      const mockNumstatOutput = `-\t-\timage.png`;
+      const mockDiffOutput = `diff --git a/image.png b/image.png
+index abc123..def456 100644
+Binary files a/image.png and b/image.png differ`;
+
+      vi.mocked(utils.executeGitCommand)
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockNumstatOutput,
+        })
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockDiffOutput,
+        });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.files).toHaveLength(1);
+        expect(result.data.files[0]?.filePath).toBe("image.png");
+        expect(result.data.files[0]?.additions).toBe(0);
+        expect(result.data.files[0]?.deletions).toBe(0);
+      }
+    });
+
+    it("大量のファイル変更を処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const fromRef = "base:main";
+      const toRef = "compare:feature";
+
+      const mockNumstatOutput = Array.from(
+        { length: 100 },
+        (_, i) => `1\t1\tfile${i}.ts`,
+      ).join("\n");
+      const mockDiffOutput = Array.from(
+        { length: 100 },
+        (_, i) => `diff --git a/file${i}.ts b/file${i}.ts
+index abc123..def456 100644
+--- a/file${i}.ts
++++ b/file${i}.ts
+@@ -1 +1 @@
+-old
++new`,
+      ).join("\n");
+
+      vi.mocked(utils.executeGitCommand)
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockNumstatOutput,
+        })
+        .mockResolvedValueOnce({
+          success: true,
+          data: mockDiffOutput,
+        });
+
+      const result = await getDiff(mockCwd, fromRef, toRef);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.files).toHaveLength(100);
+        expect(result.data.summary.totalFiles).toBe(100);
+        expect(result.data.summary.totalAdditions).toBe(100);
+        expect(result.data.summary.totalDeletions).toBe(100);
+      }
+    });
+  });
+});
+
+describe("compareBranches", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("getDiffのショートハンドとして機能する", async () => {
+    const mockCwd = "/test/repo";
+    const baseBranch = "base:main";
+    const targetBranch = "compare:feature";
+
+    const mockNumstatOutput = `5\t2\tfile.ts`;
+    const mockDiffOutput = `diff --git a/file.ts b/file.ts
+index abc123..def456 100644
+--- a/file.ts
++++ b/file.ts
+@@ -1,2 +1,5 @@
+ content`;
+
+    vi.mocked(utils.executeGitCommand)
+      .mockResolvedValueOnce({
+        success: true,
+        data: mockNumstatOutput,
+      })
+      .mockResolvedValueOnce({
+        success: true,
+        data: mockDiffOutput,
+      });
+
+    const result = await compareBranches(mockCwd, baseBranch, targetBranch);
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data.files).toHaveLength(1);
+      expect(result.data.files[0]?.filePath).toBe("file.ts");
+    }
+  });
+});
diff --git a/src/server/service/git/getStatus.test.ts b/src/server/service/git/getStatus.test.ts
new file mode 100644
index 0000000..98e22b1
--- /dev/null
+++ b/src/server/service/git/getStatus.test.ts
@@ -0,0 +1,351 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import {
+  getStatus,
+  getUncommittedChanges,
+  isWorkingDirectoryClean,
+} from "./getStatus";
+import * as utils from "./utils";
+
+vi.mock("./utils", async (importOriginal) => {
+  const actual = await importOriginal<typeof utils>();
+  return {
+    ...actual,
+    executeGitCommand: vi.fn(),
+  };
+});
+
+describe("getStatus", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  describe("正常系", () => {
+    it("Gitステータス情報を取得できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `## main...origin/main [ahead 2, behind 1]
+M  staged-modified.ts
+ M unstaged-modified.ts
+A  staged-added.ts
+?? untracked-file.ts`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getStatus(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.branch).toBe("main");
+        expect(result.data.ahead).toBe(2);
+        expect(result.data.behind).toBe(1);
+
+        expect(result.data.staged).toHaveLength(2);
+        expect(result.data.staged[0]?.filePath).toBe("staged-modified.ts");
+        expect(result.data.staged[0]?.status).toBe("modified");
+        expect(result.data.staged[1]?.filePath).toBe("staged-added.ts");
+        expect(result.data.staged[1]?.status).toBe("added");
+
+        expect(result.data.unstaged).toHaveLength(1);
+        expect(result.data.unstaged[0]?.filePath).toBe("unstaged-modified.ts");
+        expect(result.data.unstaged[0]?.status).toBe("modified");
+
+        expect(result.data.untracked).toEqual(["untracked-file.ts"]);
+        expect(result.data.conflicted).toHaveLength(0);
+      }
+
+      expect(utils.executeGitCommand).toHaveBeenCalledWith(
+        ["status", "--porcelain=v1", "-b"],
+        mockCwd,
+      );
+    });
+
+    it("名前変更されたファイルを処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `## main
+R  old-name.ts -> new-name.ts`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getStatus(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.staged).toHaveLength(1);
+        expect(result.data.staged[0]?.filePath).toBe("new-name.ts");
+        expect(result.data.staged[0]?.oldPath).toBe("old-name.ts");
+        expect(result.data.staged[0]?.status).toBe("renamed");
+      }
+    });
+
+    it("コンフリクトファイルを検出できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `## main
+UU conflicted-file.ts
+MM both-modified.ts`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getStatus(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.conflicted).toEqual([
+          "conflicted-file.ts",
+          "both-modified.ts",
+        ]);
+        expect(result.data.staged).toHaveLength(0);
+        expect(result.data.unstaged).toHaveLength(0);
+      }
+    });
+
+    it("空のリポジトリ（クリーンな状態）を処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = "## main";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getStatus(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.branch).toBe("main");
+        expect(result.data.ahead).toBe(0);
+        expect(result.data.behind).toBe(0);
+        expect(result.data.staged).toHaveLength(0);
+        expect(result.data.unstaged).toHaveLength(0);
+        expect(result.data.untracked).toHaveLength(0);
+        expect(result.data.conflicted).toHaveLength(0);
+      }
+    });
+
+    it("ブランチがupstreamを持たない場合", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `## feature-branch
+M  file.ts`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getStatus(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.branch).toBe("feature-branch");
+        expect(result.data.ahead).toBe(0);
+        expect(result.data.behind).toBe(0);
+      }
+    });
+  });
+
+  describe("エラー系", () => {
+    it("ディレクトリが存在しない場合", async () => {
+      const mockCwd = "/nonexistent/repo";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "NOT_A_REPOSITORY",
+          message: `Directory does not exist: ${mockCwd}`,
+          command: "git status --porcelain=v1 -b",
+        },
+      });
+
+      const result = await getStatus(mockCwd);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("NOT_A_REPOSITORY");
+        expect(result.error.message).toContain("Directory does not exist");
+      }
+    });
+
+    it("Gitリポジトリでない場合", async () => {
+      const mockCwd = "/test/not-a-repo";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "NOT_A_REPOSITORY",
+          message: `Not a git repository: ${mockCwd}`,
+          command: "git status --porcelain=v1 -b",
+        },
+      });
+
+      const result = await getStatus(mockCwd);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("NOT_A_REPOSITORY");
+        expect(result.error.message).toContain("Not a git repository");
+      }
+    });
+
+    it("Gitコマンドが失敗した場合", async () => {
+      const mockCwd = "/test/repo";
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: false,
+        error: {
+          code: "COMMAND_FAILED",
+          message: "Command failed",
+          command: "git status",
+          stderr: "fatal: not a git repository",
+        },
+      });
+
+      const result = await getStatus(mockCwd);
+
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        expect(result.error.code).toBe("COMMAND_FAILED");
+        expect(result.error.message).toBe("Command failed");
+      }
+    });
+  });
+
+  describe("エッジケース", () => {
+    it("特殊文字を含むファイル名を処理できる", async () => {
+      const mockCwd = "/test/repo";
+      const mockOutput = `## main
+M  file with spaces.ts
+A  日本語ファイル.ts
+?? special@#$%chars.ts`;
+
+      vi.mocked(utils.executeGitCommand).mockResolvedValue({
+        success: true,
+        data: mockOutput,
+      });
+
+      const result = await getStatus(mockCwd);
+
+      expect(result.success).toBe(true);
+      if (result.success) {
+        expect(result.data.staged[0]?.filePath).toBe("file with spaces.ts");
+        expect(result.data.staged[1]?.filePath).toBe("日本語ファイル.ts");
+        expect(result.data.untracked).toEqual(["special@#$%chars.ts"]);
+      }
+    });
+  });
+});
+
+describe("getUncommittedChanges", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("stagedとunstagedの両方の変更を取得できる", async () => {
+    const mockCwd = "/test/repo";
+    const mockOutput = `## main
+M  staged-file.ts
+ M unstaged-file.ts`;
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: true,
+      data: mockOutput,
+    });
+
+    const result = await getUncommittedChanges(mockCwd);
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data).toHaveLength(2);
+      expect(result.data.some((f) => f.filePath === "staged-file.ts")).toBe(
+        true,
+      );
+      expect(result.data.some((f) => f.filePath === "unstaged-file.ts")).toBe(
+        true,
+      );
+    }
+  });
+
+  it("重複するファイルを削除する", async () => {
+    const mockCwd = "/test/repo";
+    const mockOutput = `## main
+MM both-changed.ts`;
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: true,
+      data: mockOutput,
+    });
+
+    const result = await getUncommittedChanges(mockCwd);
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      // Conflictとして処理されるため空になる
+      expect(result.data).toHaveLength(0);
+    }
+  });
+});
+
+describe("isWorkingDirectoryClean", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("クリーンな作業ディレクトリでtrueを返す", async () => {
+    const mockCwd = "/test/repo";
+    const mockOutput = "## main";
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: true,
+      data: mockOutput,
+    });
+
+    const result = await isWorkingDirectoryClean(mockCwd);
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data).toBe(true);
+    }
+  });
+
+  it("変更がある場合falseを返す", async () => {
+    const mockCwd = "/test/repo";
+    const mockOutput = `## main
+M  modified-file.ts`;
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: true,
+      data: mockOutput,
+    });
+
+    const result = await isWorkingDirectoryClean(mockCwd);
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data).toBe(false);
+    }
+  });
+
+  it("未追跡ファイルがある場合falseを返す", async () => {
+    const mockCwd = "/test/repo";
+    const mockOutput = `## main
+?? untracked-file.ts`;
+
+    vi.mocked(utils.executeGitCommand).mockResolvedValue({
+      success: true,
+      data: mockOutput,
+    });
+
+    const result = await isWorkingDirectoryClean(mockCwd);
+
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data).toBe(false);
+    }
+  });
+});
diff --git a/src/server/service/parseCommandXml.test.ts b/src/server/service/parseCommandXml.test.ts
new file mode 100644
index 0000000..692d23d
--- /dev/null
+++ b/src/server/service/parseCommandXml.test.ts
@@ -0,0 +1,301 @@
+import { parseCommandXml } from "./parseCommandXml";
+
+describe("parseCommandXml", () => {
+  describe("command parsing", () => {
+    it("parses command-name only", () => {
+      const input = "<command-name>git status</command-name>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "git status",
+        commandArgs: undefined,
+        commandMessage: undefined,
+      });
+    });
+
+    it("parses command-name with command-args", () => {
+      const input =
+        "<command-name>git commit</command-name><command-args>-m 'test'</command-args>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "git commit",
+        commandArgs: "-m 'test'",
+        commandMessage: undefined,
+      });
+    });
+
+    it("parses command-name with command-message", () => {
+      const input =
+        "<command-name>ls</command-name><command-message>Listing files</command-message>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "ls",
+        commandArgs: undefined,
+        commandMessage: "Listing files",
+      });
+    });
+
+    it("parses all command tags together", () => {
+      const input =
+        "<command-name>npm install</command-name><command-args>--save-dev vitest</command-args><command-message>Installing test dependencies</command-message>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "npm install",
+        commandArgs: "--save-dev vitest",
+        commandMessage: "Installing test dependencies",
+      });
+    });
+
+    it("parses command tags with whitespace in content", () => {
+      const input =
+        "<command-name>\n  git status  \n</command-name><command-args>  --short  </command-args>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "\n  git status  \n",
+        commandArgs: "  --short  ",
+        commandMessage: undefined,
+      });
+    });
+
+    it("parses command tags in different order", () => {
+      const input =
+        "<command-message>Test message</command-message><command-args>-v</command-args><command-name>test command</command-name>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "test command",
+        commandArgs: "-v",
+        commandMessage: "Test message",
+      });
+    });
+  });
+
+  describe("local-command parsing", () => {
+    it("parses local-command-stdout", () => {
+      const input = "<local-command-stdout>output text</local-command-stdout>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "local-command",
+        stdout: "output text",
+      });
+    });
+
+    it("parses local-command-stdout with multiline content", () => {
+      const input =
+        "<local-command-stdout>line1\nline2\nline3</local-command-stdout>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "local-command",
+        stdout: "line1\nline2\nline3",
+      });
+    });
+
+    it("parses local-command-stdout with whitespace", () => {
+      const input =
+        "<local-command-stdout>  \n  output with spaces  \n  </local-command-stdout>";
+      const result = parseCommandXml(input);
+
+      // The regex pattern preserves all whitespace in content
+      expect(result).toEqual({
+        kind: "local-command",
+        stdout: "  \n  output with spaces  \n  ",
+      });
+    });
+  });
+
+  describe("priority: command over local-command", () => {
+    it("returns command when both command and local-command tags exist", () => {
+      const input =
+        "<command-name>test</command-name><local-command-stdout>output</local-command-stdout>";
+      const result = parseCommandXml(input);
+
+      expect(result.kind).toBe("command");
+      if (result.kind === "command") {
+        expect(result.commandName).toBe("test");
+      }
+    });
+  });
+
+  describe("fallback to text", () => {
+    it("returns text when no matching tags found", () => {
+      const input = "just plain text";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "text",
+        content: "just plain text",
+      });
+    });
+
+    it("returns text when tags are not closed properly", () => {
+      const input = "<command-name>incomplete";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "text",
+        content: "<command-name>incomplete",
+      });
+    });
+
+    it("returns text when tags are mismatched", () => {
+      const input = "<command-name>test</different-tag>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "text",
+        content: "<command-name>test</different-tag>",
+      });
+    });
+
+    it("returns text with empty string", () => {
+      const input = "";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "text",
+        content: "",
+      });
+    });
+
+    it("returns text with only unrecognized tags", () => {
+      const input = "<unknown-tag>content</unknown-tag>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "text",
+        content: "<unknown-tag>content</unknown-tag>",
+      });
+    });
+  });
+
+  describe("edge cases", () => {
+    it("handles multiple same tags (uses first match)", () => {
+      const input =
+        "<command-name>first</command-name><command-name>second</command-name>";
+      const result = parseCommandXml(input);
+
+      expect(result.kind).toBe("command");
+      if (result.kind === "command") {
+        expect(result.commandName).toBe("first");
+      }
+    });
+
+    it("handles empty tag content", () => {
+      const input = "<command-name></command-name>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "",
+        commandArgs: undefined,
+        commandMessage: undefined,
+      });
+    });
+
+    it("handles tags with special characters in content", () => {
+      const input =
+        "<command-name>git commit -m 'test &amp; demo'</command-name>";
+      const result = parseCommandXml(input);
+
+      expect(result.kind).toBe("command");
+      if (result.kind === "command") {
+        expect(result.commandName).toBe("git commit -m 'test &amp; demo'");
+      }
+    });
+
+    it("does not match nested tags (regex limitation)", () => {
+      const input = "<command-name><nested>inner</nested>outer</command-name>";
+      const result = parseCommandXml(input);
+
+      // The regex won't match properly nested tags due to [^<]* pattern
+      expect(result.kind).toBe("text");
+    });
+
+    it("handles tags with surrounding text", () => {
+      const input =
+        "Some text before <command-name>test</command-name> and after";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "test",
+        commandArgs: undefined,
+        commandMessage: undefined,
+      });
+    });
+
+    it("handles newlines between tags", () => {
+      const input =
+        "<command-name>test</command-name>\n\n<command-args>arg</command-args>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "test",
+        commandArgs: "arg",
+        commandMessage: undefined,
+      });
+    });
+
+    it("handles very long content", () => {
+      const longContent = "x".repeat(10000);
+      const input = `<command-name>${longContent}</command-name>`;
+      const result = parseCommandXml(input);
+
+      expect(result.kind).toBe("command");
+      if (result.kind === "command") {
+        expect(result.commandName).toBe(longContent);
+      }
+    });
+
+    it("handles tags with attributes (not matched)", () => {
+      const input = '<command-name attr="value">test</command-name>';
+      const result = parseCommandXml(input);
+
+      // Tags with attributes won't match because regex expects <tag> not <tag attr="...">
+      expect(result.kind).toBe("text");
+    });
+
+    it("handles self-closing tags (not matched)", () => {
+      const input = "<command-name />";
+      const result = parseCommandXml(input);
+
+      expect(result.kind).toBe("text");
+    });
+
+    it("handles Unicode content", () => {
+      const input = "<command-name>テスト コマンド 🚀</command-name>";
+      const result = parseCommandXml(input);
+
+      expect(result).toEqual({
+        kind: "command",
+        commandName: "テスト コマンド 🚀",
+        commandArgs: undefined,
+        commandMessage: undefined,
+      });
+    });
+
+    it("handles mixed content with multiple tag types", () => {
+      const input =
+        "Some text <command-name>cmd</command-name> more text <unknown>tag</unknown>";
+      const result = parseCommandXml(input);
+
+      expect(result.kind).toBe("command");
+      if (result.kind === "command") {
+        expect(result.commandName).toBe("cmd");
+      }
+    });
+  });
+});
diff --git a/src/server/service/parseJsonl.test.ts b/src/server/service/parseJsonl.test.ts
new file mode 100644
index 0000000..492505b
--- /dev/null
+++ b/src/server/service/parseJsonl.test.ts
@@ -0,0 +1,378 @@
+import { describe, expect, it } from "vitest";
+import { parseJsonl } from "./parseJsonl";
+import type { ErrorJsonl } from "./types";
+
+describe("parseJsonl", () => {
+  describe("正常系: 有効なJSONLをパースできる", () => {
+    it("単一のUserエントリをパースできる", () => {
+      const jsonl = JSON.stringify({
+        type: "user",
+        uuid: "550e8400-e29b-41d4-a716-446655440000",
+        timestamp: "2024-01-01T00:00:00.000Z",
+        message: { role: "user", content: "Hello" },
+        isSidechain: false,
+        userType: "external",
+        cwd: "/test",
+        sessionId: "session-1",
+        version: "1.0.0",
+        parentUuid: null,
+      });
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(1);
+      expect(result[0]).toHaveProperty("type", "user");
+      const entry = result[0];
+      if (entry && entry.type === "user") {
+        expect(entry.message.content).toBe("Hello");
+      }
+    });
+
+    it("単一のSummaryエントリをパースできる", () => {
+      const jsonl = JSON.stringify({
+        type: "summary",
+        summary: "This is a summary",
+        leafUuid: "550e8400-e29b-41d4-a716-446655440003",
+      });
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(1);
+      expect(result[0]).toHaveProperty("type", "summary");
+      const entry = result[0];
+      if (entry && entry.type === "summary") {
+        expect(entry.summary).toBe("This is a summary");
+      }
+    });
+
+    it("複数のエントリをパースできる", () => {
+      const jsonl = [
+        JSON.stringify({
+          type: "user",
+          uuid: "550e8400-e29b-41d4-a716-446655440000",
+          timestamp: "2024-01-01T00:00:00.000Z",
+          message: { role: "user", content: "Hello" },
+          isSidechain: false,
+          userType: "external",
+          cwd: "/test",
+          sessionId: "session-1",
+          version: "1.0.0",
+          parentUuid: null,
+        }),
+        JSON.stringify({
+          type: "summary",
+          summary: "Test summary",
+          leafUuid: "550e8400-e29b-41d4-a716-446655440002",
+        }),
+      ].join("\n");
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(2);
+      expect(result[0]).toHaveProperty("type", "user");
+      expect(result[1]).toHaveProperty("type", "summary");
+    });
+  });
+
+  describe("エラー系: 不正なJSON行をErrorJsonlとして返す", () => {
+    it("無効なJSONを渡すとエラーを投げる", () => {
+      const jsonl = "invalid json";
+
+      // parseJsonl の実装は JSON.parse をそのまま呼び出すため、
+      // 無効な JSON は例外を投げます
+      expect(() => parseJsonl(jsonl)).toThrow();
+    });
+
+    it("スキーマに合わないオブジェクトをErrorJsonlとして返す", () => {
+      const jsonl = JSON.stringify({
+        type: "unknown",
+        someField: "value",
+      });
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(1);
+      const errorEntry = result[0] as ErrorJsonl;
+      expect(errorEntry.type).toBe("x-error");
+      expect(errorEntry.lineNumber).toBe(1);
+    });
+
+    it("必須フィールドが欠けているエントリをErrorJsonlとして返す", () => {
+      const jsonl = JSON.stringify({
+        type: "user",
+        uuid: "550e8400-e29b-41d4-a716-446655440000",
+        // timestamp, message などの必須フィールドが欠けている
+      });
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(1);
+      const errorEntry = result[0] as ErrorJsonl;
+      expect(errorEntry.type).toBe("x-error");
+      expect(errorEntry.lineNumber).toBe(1);
+    });
+
+    it("正常なエントリとエラーエントリを混在して返す", () => {
+      const jsonl = [
+        JSON.stringify({
+          type: "user",
+          uuid: "550e8400-e29b-41d4-a716-446655440000",
+          timestamp: "2024-01-01T00:00:00.000Z",
+          message: { role: "user", content: "Hello" },
+          isSidechain: false,
+          userType: "external",
+          cwd: "/test",
+          sessionId: "session-1",
+          version: "1.0.0",
+          parentUuid: null,
+        }),
+        JSON.stringify({ type: "invalid-schema" }),
+        JSON.stringify({
+          type: "summary",
+          summary: "Summary text",
+          leafUuid: "550e8400-e29b-41d4-a716-446655440001",
+        }),
+      ].join("\n");
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(3);
+      expect(result[0]).toHaveProperty("type", "user");
+      expect(result[1]).toHaveProperty("type", "x-error");
+      expect(result[2]).toHaveProperty("type", "summary");
+
+      const errorEntry = result[1] as ErrorJsonl;
+      expect(errorEntry.lineNumber).toBe(2);
+    });
+  });
+
+  describe("エッジケース: 空行、トリム、複数エントリ", () => {
+    it("空文字列を渡すと空配列を返す", () => {
+      const result = parseJsonl("");
+
+      expect(result).toEqual([]);
+    });
+
+    it("空行のみを渡すと空配列を返す", () => {
+      const result = parseJsonl("\n\n\n");
+
+      expect(result).toEqual([]);
+    });
+
+    it("前後の空白をトリムする", () => {
+      const jsonl = `  
+        ${JSON.stringify({
+          type: "user",
+          uuid: "550e8400-e29b-41d4-a716-446655440000",
+          timestamp: "2024-01-01T00:00:00.000Z",
+          message: { role: "user", content: "Hello" },
+          isSidechain: false,
+          userType: "external",
+          cwd: "/test",
+          sessionId: "session-1",
+          version: "1.0.0",
+          parentUuid: null,
+        })}
+        `;
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(1);
+      expect(result[0]).toHaveProperty("type", "user");
+    });
+
+    it("行間の空行を除外する", () => {
+      const jsonl = [
+        JSON.stringify({
+          type: "user",
+          uuid: "550e8400-e29b-41d4-a716-446655440000",
+          timestamp: "2024-01-01T00:00:00.000Z",
+          message: { role: "user", content: "Hello" },
+          isSidechain: false,
+          userType: "external",
+          cwd: "/test",
+          sessionId: "session-1",
+          version: "1.0.0",
+          parentUuid: null,
+        }),
+        "",
+        "",
+        JSON.stringify({
+          type: "summary",
+          summary: "Summary text",
+          leafUuid: "550e8400-e29b-41d4-a716-446655440001",
+        }),
+      ].join("\n");
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(2);
+      expect(result[0]).toHaveProperty("type", "user");
+      expect(result[1]).toHaveProperty("type", "summary");
+    });
+
+    it("空白のみの行を除外する", () => {
+      const jsonl = [
+        JSON.stringify({
+          type: "user",
+          uuid: "550e8400-e29b-41d4-a716-446655440000",
+          timestamp: "2024-01-01T00:00:00.000Z",
+          message: { role: "user", content: "Hello" },
+          isSidechain: false,
+          userType: "external",
+          cwd: "/test",
+          sessionId: "session-1",
+          version: "1.0.0",
+          parentUuid: null,
+        }),
+        "   ",
+        "\t",
+        JSON.stringify({
+          type: "summary",
+          summary: "Summary text",
+          leafUuid: "550e8400-e29b-41d4-a716-446655440001",
+        }),
+      ].join("\n");
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(2);
+      expect(result[0]).toHaveProperty("type", "user");
+      expect(result[1]).toHaveProperty("type", "summary");
+    });
+
+    it("多数のエントリを含むJSONLをパースできる", () => {
+      const entries = Array.from({ length: 100 }, (_, i) => {
+        return JSON.stringify({
+          type: "user",
+          uuid: `550e8400-e29b-41d4-a716-${String(i).padStart(12, "0")}`,
+          timestamp: new Date(Date.UTC(2024, 0, 1, 0, 0, i)).toISOString(),
+          message: {
+            role: "user",
+            content: `Message ${i}`,
+          },
+          isSidechain: false,
+          userType: "external",
+          cwd: "/test",
+          sessionId: "session-1",
+          version: "1.0.0",
+          parentUuid:
+            i > 0
+              ? `550e8400-e29b-41d4-a716-${String(i - 1).padStart(12, "0")}`
+              : null,
+        });
+      });
+
+      const jsonl = entries.join("\n");
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(100);
+      expect(result.every((entry) => entry.type === "user")).toBe(true);
+    });
+  });
+
+  describe("行番号の正確性", () => {
+    it("スキーマ検証エラー時の行番号が正確に記録される", () => {
+      const jsonl = [
+        JSON.stringify({
+          type: "user",
+          uuid: "550e8400-e29b-41d4-a716-446655440000",
+          timestamp: "2024-01-01T00:00:00.000Z",
+          message: { role: "user", content: "Line 1" },
+          isSidechain: false,
+          userType: "external",
+          cwd: "/test",
+          sessionId: "session-1",
+          version: "1.0.0",
+          parentUuid: null,
+        }),
+        JSON.stringify({ type: "invalid", data: "schema error" }),
+        JSON.stringify({
+          type: "user",
+          uuid: "550e8400-e29b-41d4-a716-446655440001",
+          timestamp: "2024-01-01T00:00:01.000Z",
+          message: { role: "user", content: "Line 3" },
+          isSidechain: false,
+          userType: "external",
+          cwd: "/test",
+          sessionId: "session-1",
+          version: "1.0.0",
+          parentUuid: null,
+        }),
+        JSON.stringify({ type: "another-invalid" }),
+      ].join("\n");
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(4);
+      expect((result[1] as ErrorJsonl).lineNumber).toBe(2);
+      expect((result[1] as ErrorJsonl).type).toBe("x-error");
+      expect((result[3] as ErrorJsonl).lineNumber).toBe(4);
+      expect((result[3] as ErrorJsonl).type).toBe("x-error");
+    });
+
+    it("空行フィルタ後の行番号が正確に記録される", () => {
+      const jsonl = ["", "", JSON.stringify({ type: "invalid-schema" })].join(
+        "\n",
+      );
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(1);
+      // 空行がフィルタされた後のインデックスは0だが、lineNumberは1として記録される
+      expect((result[0] as ErrorJsonl).lineNumber).toBe(1);
+    });
+  });
+
+  describe("ConversationSchemaのバリエーション", () => {
+    it("オプショナルフィールドを含むUserエントリをパースできる", () => {
+      const jsonl = JSON.stringify({
+        type: "user",
+        uuid: "550e8400-e29b-41d4-a716-446655440000",
+        timestamp: "2024-01-01T00:00:00.000Z",
+        message: { role: "user", content: "Hello" },
+        isSidechain: true,
+        userType: "external",
+        cwd: "/test",
+        sessionId: "session-1",
+        version: "1.0.0",
+        parentUuid: "550e8400-e29b-41d4-a716-446655440099",
+        gitBranch: "main",
+        isMeta: false,
+      });
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(1);
+      const entry = result[0];
+      if (entry && entry.type === "user") {
+        expect(entry.isSidechain).toBe(true);
+        expect(entry.parentUuid).toBe("550e8400-e29b-41d4-a716-446655440099");
+        expect(entry.gitBranch).toBe("main");
+      }
+    });
+
+    it("nullableフィールドがnullのエントリをパースできる", () => {
+      const jsonl = JSON.stringify({
+        type: "user",
+        uuid: "550e8400-e29b-41d4-a716-446655440000",
+        timestamp: "2024-01-01T00:00:00.000Z",
+        message: { role: "user", content: "Hello" },
+        isSidechain: false,
+        userType: "external",
+        cwd: "/test",
+        sessionId: "session-1",
+        version: "1.0.0",
+        parentUuid: null,
+      });
+
+      const result = parseJsonl(jsonl);
+
+      expect(result).toHaveLength(1);
+      const entry = result[0];
+      if (entry && entry.type === "user") {
+        expect(entry.parentUuid).toBeNull();
+      }
+    });
+  });
+});
diff --git a/src/server/service/session/SessionRepository.test.ts b/src/server/service/session/SessionRepository.test.ts
index 187a765..ca7401a 100644
--- a/src/server/service/session/SessionRepository.test.ts
+++ b/src/server/service/session/SessionRepository.test.ts
@@ -5,9 +5,9 @@ import type { Conversation } from "../../../lib/conversation-schema";
 import { PersistentService } from "../../lib/storage/FileCacheStorage/PersistantService";
 import { decodeProjectId } from "../project/id";
 import type { ErrorJsonl, SessionDetail, SessionMeta } from "../types";
-import { VirtualConversationDatabase } from "./PredictSessionsDatabase";
 import { SessionMetaService } from "./SessionMetaService";
 import { SessionRepository } from "./SessionRepository";
+import { VirtualConversationDatabase } from "./VirtualConversationDatabase";
 
 /**
  * Helper function to create a FileSystem mock layer
diff --git a/src/server/service/session/SessionRepository.ts b/src/server/service/session/SessionRepository.ts
index 8e3561f..3a495b4 100644
--- a/src/server/service/session/SessionRepository.ts
+++ b/src/server/service/session/SessionRepository.ts
@@ -1,14 +1,13 @@
 import { resolve } from "node:path";
 import { FileSystem } from "@effect/platform";
 import { Context, Effect, Layer, Option } from "effect";
-import { uniqBy } from "es-toolkit";
 import { parseCommandXml } from "../parseCommandXml";
 import { parseJsonl } from "../parseJsonl";
 import { decodeProjectId } from "../project/id";
 import type { Session, SessionDetail } from "../types";
 import { decodeSessionId, encodeSessionId } from "./id";
-import { VirtualConversationDatabase } from "./PredictSessionsDatabase";
 import { SessionMetaService } from "./SessionMetaService";
+import { VirtualConversationDatabase } from "./VirtualConversationDatabase";
 
 const getSession = (projectId: string, sessionId: string) =>
   Effect.gen(function* () {
@@ -75,25 +74,7 @@ const getSession = (projectId: string, sessionId: string) =>
             id: sessionId,
             jsonlFilePath: sessionPath,
             meta,
-            conversations: isBroken
-              ? conversations
-              : uniqBy(mergedConversations, (item) => {
-                  switch (item.type) {
-                    case "system":
-                      return `${item.type}-${item.uuid}`;
-                    case "assistant":
-                      return `${item.type}-${item.message.id}`;
-                    case "user":
-                      return `${item.type}-${item.message.content}`;
-                    case "summary":
-                      return `${item.type}-${item.leafUuid}`;
-                    case "x-error":
-                      return `${item.type}-${item.lineNumber}-${item.line}`;
-                    default:
-                      item satisfies never;
-                      throw new Error(`Unknown conversation type: ${item}`);
-                  }
-                }),
+            conversations: isBroken ? conversations : mergedConversations,
             lastModifiedAt: Option.getOrElse(stat.mtime, () => new Date()),
           };
 
diff --git a/src/server/service/session/VirtualConversationDatabase.test.ts b/src/server/service/session/VirtualConversationDatabase.test.ts
index 4771f0b..77204f2 100644
--- a/src/server/service/session/VirtualConversationDatabase.test.ts
+++ b/src/server/service/session/VirtualConversationDatabase.test.ts
@@ -1,7 +1,7 @@
 import { Effect } from "effect";
 import type { Conversation } from "../../../lib/conversation-schema";
 import type { ErrorJsonl } from "../types";
-import { VirtualConversationDatabase } from "./PredictSessionsDatabase";
+import { VirtualConversationDatabase } from "./VirtualConversationDatabase";
 
 describe("VirtualConversationDatabase", () => {
   describe("getProjectVirtualConversations", () => {