fix(desktop): stop auto-opening tool previews

Drop gateway-event preview registration so HTML artifacts from tool results
no longer pop the rail. De-dupe the inline preview card label.

apps/desktop/src/app/session/hooks/use-preview-routing.test.tsx

@@ -120,31 +120,7 @@ describe('usePreviewRouting', () => {
     expect(window.hermesDesktop.normalizePreviewTarget).not.toHaveBeenCalled()
   })
 
-  it('registers structured tool-result preview targets', async () => {
-    render(
-      <PreviewRoutingHarness
-        onEvent={handler => {
-          handleEvent = handler
-        }}
-      />
-    )
-
-    act(() =>
-      handleEvent({
-        payload: { path: './dist/index.html' },
-        session_id: 'session-1',
-        type: 'tool.complete'
-      })
-    )
-
-    await waitFor(() => {
-      expect($previewTarget.get()?.source).toBe('./dist/index.html')
-    })
-
-    expect(window.localStorage.getItem('hermes.desktop.sessionPreviews.v1')).toContain('./dist/index.html')
-  })
-
-  it('registers html previews from edit inline diffs', async () => {
+  it('does not auto-open a preview from tool results', async () => {
     render(
       <PreviewRoutingHarness
         onEvent={handler => {
@@ -160,9 +136,9 @@ describe('usePreviewRouting', () => {
         type: 'tool.complete'
       })
     )
+    act(() => handleEvent({ payload: { path: './dist/index.html' }, session_id: 'session-1', type: 'tool.complete' }))
 
-    await waitFor(() => {
-      expect($previewTarget.get()?.source).toBe('preview-demo.html')
-    })
+    expect($previewTarget.get()).toBeNull()
+    expect(window.localStorage.getItem('hermes.desktop.sessionPreviews.v1')).toBeNull()
   })
 })

apps/desktop/src/app/session/hooks/use-preview-routing.ts

@@ -10,8 +10,7 @@ import {
   getSessionPreviewRecord,
   progressPreviewServerRestart,
   requestPreviewReload,
-  setPreviewTarget,
-  setSessionPreviewTarget
+  setPreviewTarget
 } from '@/store/preview'
 import { $currentCwd } from '@/store/session'
 import type { RpcEvent } from '@/types/hermes'
@@ -40,53 +39,6 @@ function activePreviewSessionId(
   return selectedStoredSessionId || routedSessionId || activeSessionIdRef.current || ''
 }
 
-function looksLikePreviewTarget(value: string): boolean {
-  return /^https?:\/\//i.test(value) || /^file:\/\//i.test(value) || /^(?:\/|\.{1,2}\/|~\/).+/.test(value)
-}
-
-function stripAnsi(value: string): string {
-  return value.replace(new RegExp(`${String.fromCharCode(27)}\\[[0-9;]*m`, 'g'), '')
-}
-
-function htmlPathFromInlineDiff(value: string): string {
-  const cleaned = stripAnsi(value).replace(/^\s*┊\s*review diff\s*\n/i, '')
-
-  for (const match of cleaned.matchAll(/(?:^|\s)(?:[ab]\/)?([^\s]+\.html?)(?=\s|$)/gi)) {
-    const candidate = match[1]?.trim()
-
-    if (candidate) {
-      return candidate
-    }
-  }
-
-  return ''
-}
-
-function structuredPreviewCandidate(payload: unknown): string {
-  const record = asRecord(payload)
-  const fields = ['url', 'target', 'path', 'file', 'filepath', 'preview']
-
-  for (const field of fields) {
-    const value = record[field]
-
-    if (typeof value === 'string') {
-      const target = value.trim()
-
-      if (target && looksLikePreviewTarget(target)) {
-        return target
-      }
-    }
-  }
-
-  const inlineDiff = record.inline_diff
-
-  if (typeof inlineDiff === 'string') {
-    return htmlPathFromInlineDiff(inlineDiff)
-  }
-
-  return ''
-}
-
 export function usePreviewRouting({
   activeSessionIdRef,
   baseHandleGatewayEvent,
@@ -99,6 +51,10 @@ export function usePreviewRouting({
   const previewRegistry = useStore($sessionPreviewRegistry)
   const previewSessionId = activePreviewSessionId(activeSessionIdRef, routedSessionId, selectedStoredSessionId)
 
+  // Restore a *user-opened* preview when its session becomes active. Tool
+  // results no longer auto-register/open a preview — the inline preview card in
+  // the tool row is the only entry point, so HTML artifacts never pop the rail
+  // open on their own.
   useEffect(() => {
     if (currentView !== 'chat' || !previewSessionId) {
       setPreviewTarget(null)
@@ -111,53 +67,6 @@ export function usePreviewRouting({
     setPreviewTarget(record?.normalized ?? null)
   }, [currentView, previewRegistry, previewSessionId])
 
-  const registerStructuredPreview = useCallback(
-    async (event: RpcEvent) => {
-      if (
-        event.session_id &&
-        event.session_id !== activeSessionIdRef.current &&
-        event.session_id !== previewSessionId
-      ) {
-        return
-      }
-
-      if (!event.type.startsWith('tool.')) {
-        return
-      }
-
-      if (!previewSessionId) {
-        return
-      }
-
-      const candidate = structuredPreviewCandidate(event.payload)
-
-      if (!candidate) {
-        return
-      }
-
-      const desktop = window.hermesDesktop
-
-      if (!desktop?.normalizePreviewTarget) {
-        return
-      }
-
-      const sessionId = previewSessionId
-      const cwd = currentCwd || ''
-      const target = await desktop.normalizePreviewTarget(candidate, cwd || undefined).catch(() => null)
-
-      if (
-        !target ||
-        sessionId !== activePreviewSessionId(activeSessionIdRef, routedSessionId, selectedStoredSessionId) ||
-        $currentCwd.get() !== cwd
-      ) {
-        return
-      }
-
-      setSessionPreviewTarget(sessionId, target, 'tool-result', candidate)
-    },
-    [activeSessionIdRef, currentCwd, previewSessionId, routedSessionId, selectedStoredSessionId]
-  )
-
   const restartPreviewServer = useCallback(
     async (url: string, context?: string) => {
       const sessionId = activeSessionIdRef.current
@@ -210,13 +119,14 @@ export function usePreviewRouting({
         return
       }
 
-      void registerStructuredPreview(event)
-
+      // Only refresh an already-open live preview when a file changes; never
+      // open one unprompted. (Preview links are surfaced from the tool row into
+      // the status stack — see tool-fallback.tsx.)
       if ($previewTarget.get()?.kind === 'url' && gatewayEventCompletedFileDiff(event)) {
         requestPreviewReload()
       }
     },
-    [activeSessionIdRef, baseHandleGatewayEvent, registerStructuredPreview]
+    [activeSessionIdRef, baseHandleGatewayEvent]
   )
 
   return { handleDesktopGatewayEvent, restartPreviewServer }

apps/desktop/src/components/chat/preview-attachment.tsx

@@ -104,16 +104,15 @@ export function PreviewAttachment({ source = 'manual', target }: { source?: Prev
   }
 
   return (
-    <div className="flex w-full max-w-160 flex-wrap items-center gap-2.5 rounded-lg border border-border/55 bg-card/55 px-2.5 py-1.5 text-sm">
-      <span className="grid size-7 shrink-0 place-items-center rounded-md bg-muted/55 text-muted-foreground/85">
+    <div className="flex w-full max-w-160 items-center gap-2 rounded-lg border border-border/55 bg-card/55 px-2.5 py-1.5 text-sm">
+      <span className="grid size-6 shrink-0 place-items-center rounded-md bg-muted/55 text-muted-foreground/85">
         <MonitorPlay className="size-3.5" />
       </span>
-      <div className="min-w-0 flex-1">
-        <div className="truncate text-[0.78rem] font-medium leading-[1.15rem] text-foreground/90">{name}</div>
-        <div className="truncate font-mono text-[0.66rem] leading-4 text-muted-foreground/70">{target}</div>
-      </div>
+      <span className="min-w-0 flex-1 truncate text-[0.78rem] font-medium text-foreground/90" title={target}>
+        {name}
+      </span>
       <button
-        className="ml-auto shrink-0 rounded-md border border-border/55 bg-background/40 px-2 py-1 text-[0.7rem] font-medium text-muted-foreground transition-colors hover:bg-accent/55 hover:text-foreground disabled:opacity-50 max-[28rem]:ml-9 max-[28rem]:w-[calc(100%-2.25rem)]"
+        className="shrink-0 rounded-md border border-border/55 bg-background/40 px-2 py-1 text-[0.7rem] font-medium text-muted-foreground transition-colors hover:bg-accent/55 hover:text-foreground disabled:opacity-50"
         disabled={opening}
         onClick={() => void togglePreview()}
         type="button"