NousResearch/hermes-agent · warning · Error

r.couldNotPreview(path)

Error message

r.couldNotPreview(path)

What it means

Thrown by the right sidebar file browser's previewFile handler in the desktop app. It resolves a clicked file path against the session's effective cwd via normalizeOrLocalPreviewTarget; a null result means the path cannot be turned into any previewable target (unsupported scheme, unreachable location, unresolvable relative path). The catch converts it into an error notification, so it signals 'this file cannot be previewed from here' rather than crashing.

Source

Thrown at apps/desktop/src/app/right-sidebar/index.tsx:66

    rootError,
    rootLoading,
    setNodeOpen
  } = useProjectTree(hasWorkspace ? currentCwd : '')

  const cwdName =
    effectiveCwd
      .split(/[\\/]+/)
      .filter(Boolean)
      .pop() ?? effectiveCwd

  const canCollapse = Object.values(openState).some(Boolean)

  const previewFile = async (path: string) => {
    try {
      const preview = await normalizeOrLocalPreviewTarget(path, effectiveCwd || undefined)

      if (!preview) {
        throw new Error(r.couldNotPreview(path))
      }

      openPreview(preview, 'file-browser')
    } catch (error) {
      notifyError(error, r.previewUnavailable)
    }
  }

  return (
    <aside
      aria-label={r.aria}
      className={cn(
        'before:pointer-events-none relative flex h-full w-full min-w-0 flex-col overflow-hidden border-(--ui-stroke-secondary) bg-(--ui-sidebar-surface-background) pt-(--titlebar-height) text-(--ui-text-tertiary)',
        panesFlipped
          ? 'border-r shadow-[inset_-0.0625rem_0_0_color-mix(in_srgb,white_18%,transparent)]'
          : 'border-l shadow-[inset_0.0625rem_0_0_color-mix(in_srgb,white_18%,transparent)]'
      )}
    >

View on GitHub (pinned to c896c09c42)

Solutions

1. Confirm effectiveCwd is set for the session so relative paths resolve; reopen the workspace if cwd is empty.
2. For remote backends, preview only files accessible from the client (mounted path or served URL).
3. Refresh the file browser if the file may have been deleted or moved.
4. As a developer: pre-filter browser entries with a canPreview check so unpreviewable entries are not clickable.

Example fix

// before
const preview = await normalizeOrLocalPreviewTarget(path, effectiveCwd || undefined)
if (!preview) {
  throw new Error(r.couldNotPreview(path))
}

// after — only enable preview for entries the resolver will accept
const preview = await normalizeOrLocalPreviewTarget(path, effectiveCwd || undefined)
if (!preview) {
  notifyError(new Error(r.couldNotPreview(path)), r.previewUnavailable)
  return
}

const canPreview = (p: string) => p.startsWith('/') || p.startsWith('http') || Boolean(effectiveCwd)
if (!canPreview(path)) return

const isLocallyResolvable = (p: string, cwd?: string): boolean =>
  p.startsWith('/') || /^https?:/.test(p) || Boolean(cwd && !p.startsWith('\\\\'))

try {
  const preview = await normalizeOrLocalPreviewTarget(path, effectiveCwd || undefined)
  if (!preview) throw new Error(r.couldNotPreview(path))
  openPreview(preview, 'file-browser')
} catch (error) {
  notifyError(error, r.previewUnavailable) // toast, tree stays usable
}

When it happens

Trigger: Clicking a file in the browser tree that is a directory-like entry or unsupported type, a path on a remote backend unreachable from the client, a relative path that fails to anchor because effectiveCwd is empty, or a file deleted between listing and click.

Common situations: Desktop app over SSH/URL backend where the file tree reflects the backend filesystem; workspace roots with symlinks the resolver refuses; empty-cwd sessions (brand-new session before cwd sync).

Related errors

• c.couldNotPreview(attachment.label)
• Could not open preview target: ${item.target}
• Not a directory: ${watchDir}
• Invalid preview URL
• Could not create directory: ${error.message}

AI-assisted analysis of NousResearch/hermes-agent@c896c09c42 (2026-08-14). Data as JSON: /api/errors/3a0396d09e7ac78b. Report an issue: GitHub.