fix(web): folder links from chat open in the file tree

apps/web/src/components/files/FileBrowserPanel.tsx

@@ -30,7 +30,7 @@ interface FileBrowserPanelProps {
   environmentId: EnvironmentId;
   cwd: string;
   projectName: string;
-  /** File currently open in the preview pane; revealed and selected in the tree. */
+  /** Entry currently open in the surface; revealed and selected in the tree. A directory is expanded. */
   selectedPath: string | null;
   /** Bumped when the same path should be revealed again (e.g. re-opened from search). */
   selectedPathRevealId: number;
@@ -299,8 +299,13 @@ export default function FileBrowserPanel({
     ) {
       return;
     }
-    if (entryKinds.get(selectedPath) !== "file") return;
-    const selectedItem = model.getItem(selectedPath);
+    const selectedKind = entryKinds.get(selectedPath);
+    if (selectedKind === undefined) return;
+    // Directory rows are registered with a trailing slash (see treePath).
+    const selectedItem =
+      selectedKind === "directory"
+        ? model.getItem(`${selectedPath}/`)
+        : model.getItem(selectedPath);
     if (!selectedItem) return;
 
     // A selection that originated inside the tree (clicking a row, possibly
@@ -334,8 +339,12 @@ export default function FileBrowserPanel({
       if (item && "expand" in item) item.expand();
     }
 
+    if (selectedKind === "directory" && "expand" in selectedItem) selectedItem.expand();
     selectedItem.select();
-    model.scrollToPath(selectedPath, { focus: true, offset: "center" });
+    model.scrollToPath(selectedKind === "directory" ? `${selectedPath}/` : selectedPath, {
+      focus: true,
+      offset: "center",
+    });
     queueMicrotask(() => {
       syncingSelectionRef.current = false;
     });

apps/web/src/components/files/FilePreviewPanel.test.ts

@@ -6,6 +6,7 @@ import {
   remapFileCommentAnnotations,
 } from "./fileCommentAnnotations";
 import {
+  isDirectoryEntry,
   isMarkdownPreviewFile,
   setMarkdownTaskChecked,
   shouldShowFileExplorer,
@@ -120,3 +121,22 @@ describe("setMarkdownTaskChecked", () => {
     expect(setMarkdownTaskChecked(markdown, 200, true)).toBe(markdown);
   });
 });
+
+describe("isDirectoryEntry", () => {
+  const entries = [
+    { kind: "directory" as const, path: ".agents" },
+    { kind: "directory" as const, path: ".agents/skills" },
+    { kind: "file" as const, path: ".agents/skills/SKILL.md" },
+  ];
+
+  it("recognizes a listed directory with or without a trailing slash", () => {
+    expect(isDirectoryEntry(entries, ".agents/skills")).toBe(true);
+    expect(isDirectoryEntry(entries, ".agents/skills/")).toBe(true);
+  });
+
+  it("does not treat files or unknown paths as directories", () => {
+    expect(isDirectoryEntry(entries, ".agents/skills/SKILL.md")).toBe(false);
+    expect(isDirectoryEntry(entries, "missing")).toBe(false);
+    expect(isDirectoryEntry(undefined, ".agents")).toBe(false);
+  });
+});

apps/web/src/components/files/FilePreviewPanel.tsx

@@ -68,6 +68,7 @@ import { resolveCenteredFileLineScrollTop } from "./fileLineReveal";
 import { DiffCommentAnnotation } from "../diffs/DiffCommentAnnotation";
 import { projectFileCacheKey, projectFileEditorCacheKey } from "./fileContentRevision";
 import {
+  isDirectoryEntry,
   isMarkdownPreviewFile,
   setMarkdownTaskChecked,
   shouldShowFileExplorer,
@@ -76,6 +77,7 @@ import { useFileSaveCoordinator } from "./useFileSaveCoordinator";
 import {
   getOptimisticProjectFileQueryData,
   setProjectFileQueryData,
+  useProjectEntriesQuery,
   useProjectFileQuery,
 } from "./projectFilesQueryState";
 
@@ -956,7 +958,7 @@ export default function FilePreviewPanel({
   environmentId,
   cwd,
   projectName,
-  relativePath,
+  relativePath: selectedPath,
   attachment,
   threadRef,
   composerDraftTarget,
@@ -980,6 +982,15 @@ export default function FilePreviewPanel({
   const openPreview = useAtomCommand(previewEnvironment.open, {
     reportFailure: false,
   });
+  // A chat link cannot tell a folder from a file, so a folder arrives as a file
+  // surface. The tree already knows every entry; a folder is revealed there
+  // and gets no preview pane instead of a read error.
+  const entries = useProjectEntriesQuery(environmentId, cwd);
+  const isDirectory =
+    selectedPath !== null &&
+    attachment === undefined &&
+    isDirectoryEntry(entries.data?.entries, selectedPath);
+  const relativePath = isDirectory ? null : selectedPath;
   const isVideo = relativePath !== null && isWorkspaceVideoPreviewPath(relativePath);
   const isImage = relativePath !== null && !isVideo && isWorkspaceImagePreviewPath(relativePath);
   const isMedia = isImage || isVideo;
@@ -1342,7 +1353,7 @@ export default function FilePreviewPanel({
               environmentId={environmentId}
               cwd={cwd}
               projectName={projectName}
-              selectedPath={relativePath}
+              selectedPath={selectedPath}
               selectedPathRevealId={revealRequestId}
               onOpenFile={onOpenFile}
               workspaceMutationId={workspaceMutationId}

apps/web/src/components/files/filePreviewMode.ts

@@ -13,6 +13,19 @@ export function shouldShowFileExplorer(input: {
   return input.explorerOpen || input.relativePath === null;
 }
 
+/** Whether a workspace path names a directory in the listed entries, with or without a trailing slash. */
+export function isDirectoryEntry(
+  entries:
+    | ReadonlyArray<{ readonly kind: "file" | "directory"; readonly path: string }>
+    | undefined,
+  relativePath: string,
+): boolean {
+  const normalizedPath = relativePath.replace(/\/+$/, "");
+  return (
+    entries?.some((entry) => entry.kind === "directory" && entry.path === normalizedPath) ?? false
+  );
+}
+
 export function setMarkdownTaskChecked(
   markdown: string,
   markerOffset: number,