feat: open local file links from chat

app/api/files/[...path]/route.ts

@@ -7,6 +7,7 @@ import {
   isWindowsAbsolutePath,
   normalizeSlashes,
 } from "@/lib/file-access";
+import { isFilePathReferencedBySession } from "@/lib/session-file-references";
 
 const IGNORED_NAMES = new Set([
   "node_modules", ".git", ".next", "dist", "build", "__pycache__",
@@ -20,6 +21,10 @@ const TEXT_PREVIEW_MAX_BYTES = 256 * 1024;
 const IMAGE_PREVIEW_MAX_BYTES = 10 * 1024 * 1024;
 const DOCX_PREVIEW_MAX_BYTES = 10 * 1024 * 1024;
 
+const FILE_REQUEST_TYPES = ["list", "read", "download", "meta", "preview", "watch"] as const;
+type FileRequestType = typeof FILE_REQUEST_TYPES[number];
+const FILE_REQUEST_TYPE_SET = new Set<string>(FILE_REQUEST_TYPES);
+
 const IMAGE_EXT_TO_MIME: Record<string, string> = {
   png: "image/png",
   jpg: "image/jpeg",
@@ -99,6 +104,10 @@ function filePathFromSegments(segments: string[]): string {
   return "/" + joined.replace(/^\/+/, "");
 }
 
+function parseFileRequestType(value: string): FileRequestType | null {
+  return FILE_REQUEST_TYPE_SET.has(value) ? (value as FileRequestType) : null;
+}
+
 function createFileBodyStream(filePath: string, range?: { start: number; end: number }): ReadableStream<Uint8Array> {
   const fileStream = fs.createReadStream(filePath, range);
   let closed = false;
@@ -283,10 +292,20 @@ export async function GET(
   try {
     const { path: segments } = await params;
     const filePath = filePathFromSegments(segments);
-    const type = request.nextUrl.searchParams.get("type") ?? "list";
+    const rawType = request.nextUrl.searchParams.get("type") ?? "list";
+    const type = parseFileRequestType(rawType);
+    if (!type) {
+      return NextResponse.json({ error: "Invalid file request type" }, { status: 400 });
+    }
+    const sessionId = request.nextUrl.searchParams.get("sessionId");
 
     const allowedRoots = await getAllowedFileRoots();
-    if (!isFilePathAllowed(filePath, allowedRoots)) {
+    const allowedByRoot = isFilePathAllowed(filePath, allowedRoots);
+    const allowedBySessionReference =
+      !allowedByRoot &&
+      type !== "list" &&
+      await isFilePathReferencedBySession(filePath, sessionId);
+    if (!allowedByRoot && !allowedBySessionReference) {
       return NextResponse.json({ error: "Access denied" }, { status: 403 });
     }
 

components/AppShell.tsx

@@ -12,6 +12,7 @@ import { PluginsConfig } from "./PluginsConfig";
 import { BranchNavigator } from "./BranchNavigator";
 import { useTheme } from "@/hooks/useTheme";
 import { useIsMobile } from "@/hooks/useIsMobile";
+import { getFileName } from "@/lib/file-paths";
 import { buildAtMentionText } from "@/lib/file-fuzzy";
 import type { SessionInfo, SessionTreeNode } from "@/lib/types";
 import type { ChatInputHandle } from "./ChatInput";
@@ -286,18 +287,24 @@ export function AppShell() {
     }
   }, [selectedSession, router]);
 
-  const handleOpenFile = useCallback((filePath: string, fileName: string) => {
+  const handleOpenFile = useCallback((filePath: string, fileName: string, sourceSessionId?: string | null) => {
     const tabId = `file:${filePath}`;
     setFileTabs((prev) => {
-      if (prev.find((t) => t.id === tabId)) return prev;
-      return [...prev, { id: tabId, label: fileName, filePath }];
+      const existing = prev.find((t) => t.id === tabId);
+      if (!existing) return [...prev, { id: tabId, label: fileName, filePath, sourceSessionId }];
+      if (!sourceSessionId || existing.sourceSessionId === sourceSessionId) return prev;
+      return prev.map((t) => t.id === tabId ? { ...t, sourceSessionId } : t);
     });
     setActiveFileTabId(tabId);
     setRightPanelOpen(true);
     // On mobile the file panel is full-screen; close the drawer so it shows.
     if (isMobile) setSidebarOpen(false);
   }, [isMobile]);
 
+  const handleOpenLinkedFile = useCallback((filePath: string) => {
+    handleOpenFile(filePath, getFileName(filePath), selectedSession?.id ?? null);
+  }, [handleOpenFile, selectedSession?.id]);
+
   const handleCloseFileTab = useCallback((tabId: string) => {
     setFileTabs((prev) => {
       const next = prev.filter((t) => t.id !== tabId);
@@ -977,6 +984,7 @@ export function AppShell() {
               onSessionStatsChange={handleSessionStatsChange}
               onSessionStatsPanelOpen={openSessionStatsPanel}
               onContextUsageChange={handleContextUsageChange}
+              onOpenFile={handleOpenLinkedFile}
             />
           ) : showPlaceholder ? (
             activeCwd ? (
@@ -1027,7 +1035,11 @@ export function AppShell() {
         {/* File content */}
         <div style={{ flex: 1, overflow: "hidden" }}>
           {activeFileTab?.filePath ? (
-            <FileViewer filePath={activeFileTab.filePath} cwd={activeCwd ?? undefined} />
+            <FileViewer
+              filePath={activeFileTab.filePath}
+              cwd={activeCwd ?? undefined}
+              sourceSessionId={activeFileTab.sourceSessionId}
+            />
           ) : (
             <div style={{ height: "100%", display: "flex", alignItems: "center", justifyContent: "center", color: "var(--text-dim)", fontSize: 12 }}>
               No file open

components/ChatWindow.tsx

@@ -24,6 +24,7 @@ interface Props {
   onSessionStatsChange?: (stats: SessionStatsInfo | null) => void;
   onSessionStatsPanelOpen?: () => void;
   onContextUsageChange?: (usage: { percent: number | null; contextWindow: number; tokens: number | null } | null) => void;
+  onOpenFile?: (filePath: string) => void;
 }
 
 function phaseLabel(phase: AgentPhase): string {
@@ -43,7 +44,7 @@ const CHAT_MINIMAP_WIDTH = 36;
 const CHAT_COLUMN_PADDING = 16;
 const CHAT_INPUT_RIGHT_PADDING = CHAT_COLUMN_PADDING + CHAT_MINIMAP_WIDTH;
 
-export function ChatWindow({ session, newSessionCwd, onAgentEnd, onSessionCreated, onSessionForked, modelsRefreshKey, chatInputRef, onBranchDataChange, onSystemPromptChange, onSessionStatsChange, onSessionStatsPanelOpen, onContextUsageChange }: Props) {
+export function ChatWindow({ session, newSessionCwd, onAgentEnd, onSessionCreated, onSessionForked, modelsRefreshKey, chatInputRef, onBranchDataChange, onSystemPromptChange, onSessionStatsChange, onSessionStatsPanelOpen, onContextUsageChange, onOpenFile }: Props) {
   const { soundEnabled, onSoundToggle, playDoneSound, unlockAudio } = useAudio();
   const isMobile = useIsMobile();
 
@@ -133,6 +134,7 @@ export function ChatWindow({ session, newSessionCwd, onAgentEnd, onSessionCreate
   const messageRefs = useMessageRefs(visibleMessages.length);
 
   const isEmptyNew = isNew && messages.length === 0 && !streamState.isStreaming && !agentRunning;
+  const messageCwd = session?.cwd ?? newSessionCwd ?? undefined;
 
   const availableThinkingLevels = displayModelValue
     ? (modelThinkingLevels[`${displayModelValue.provider}:${displayModelValue.modelId}`] ?? null)
@@ -349,6 +351,8 @@ export function ChatWindow({ session, newSessionCwd, onAgentEnd, onSessionCreate
                     message={msg}
                     toolResults={toolResultsMap}
                     modelNames={modelNames}
+                    cwd={messageCwd}
+                    onOpenFile={onOpenFile}
                     entryId={entryIds[idx]}
                     onFork={agentRunning || isNew || (idx === 0 && msg.role === "user") ? undefined : handleFork}
                     forking={forkingEntryId === entryIds[idx]}
@@ -372,7 +376,7 @@ export function ChatWindow({ session, newSessionCwd, onAgentEnd, onSessionCreate
             })()}
 
             {streamState.isStreaming && streamState.streamingMessage && (
-              <MessageView message={streamState.streamingMessage as AgentMessage} isStreaming modelNames={modelNames} />
+              <MessageView message={streamState.streamingMessage as AgentMessage} isStreaming modelNames={modelNames} cwd={messageCwd} onOpenFile={onOpenFile} />
             )}
 
             {agentRunning && !streamState.streamingMessage && (