perf(workspace): stop the sidebar fetching palette data on every route

apps/sim/app/workspace/[workspaceId]/chat/[chatId]/page.tsx

@@ -1,8 +1,13 @@
 import { Suspense } from 'react'
+import { dehydrate, HydrationBoundary } from '@tanstack/react-query'
 import type { Metadata } from 'next'
+import { notFound } from 'next/navigation'
 import { getSession } from '@/lib/auth'
+import { isChatEnabled } from '@/lib/core/config/env-flags'
+import { getQueryClient } from '@/app/_shell/providers/get-query-client'
 import { Home } from '@/app/workspace/[workspaceId]/home/home'
 import { HomeFallback } from '@/app/workspace/[workspaceId]/home/home-fallback'
+import { prefetchHomeSurface } from '@/app/workspace/[workspaceId]/home/prefetch'
 import { resolveTableViewsEnabled } from '@/app/workspace/[workspaceId]/home/resolve-table-views-flag'
 
 export const metadata: Metadata = {
@@ -17,18 +22,30 @@ interface ChatPageProps {
 }
 
 export default async function ChatPage({ params }: ChatPageProps) {
+  // The layout 404s too, but pages and layouts resolve concurrently — without this
+  // the prefetch below still fires on its way out.
+  if (!isChatEnabled) {
+    notFound()
+  }
+
   const [{ workspaceId, chatId }, session] = await Promise.all([params, getSession()])
   const userId = session?.user?.id
-  const tableViewsEnabled = await resolveTableViewsEnabled(workspaceId, userId)
+  const queryClient = getQueryClient()
+  const [tableViewsEnabled] = await Promise.all([
+    resolveTableViewsEnabled(workspaceId, userId),
+    prefetchHomeSurface(queryClient, workspaceId, userId),
+  ])
   return (
-    <Suspense fallback={<HomeFallback />}>
-      <Home
-        key={chatId}
-        chatId={chatId}
-        userName={session?.user?.name}
-        userId={userId}
-        tableViewsEnabled={tableViewsEnabled}
-      />
-    </Suspense>
+    <HydrationBoundary state={dehydrate(queryClient)}>
+      <Suspense fallback={<HomeFallback />}>
+        <Home
+          key={chatId}
+          chatId={chatId}
+          userName={session?.user?.name}
+          userId={userId}
+          tableViewsEnabled={tableViewsEnabled}
+        />
+      </Suspense>
+    </HydrationBoundary>
   )
 }

apps/sim/app/workspace/[workspaceId]/files/prefetch.ts

@@ -3,6 +3,7 @@ import { listWorkspaceFileFoldersContract } from '@/lib/api/contracts/workspace-
 import { listWorkspaceFileFolders } from '@/lib/uploads/contexts/workspace/workspace-file-folder-manager'
 import { getWorkspaceHostContextForViewer } from '@/lib/workspaces/host-context'
 import { prefetchResourceListChrome } from '@/app/workspace/[workspaceId]/lib/prefetch-resource-list-chrome'
+import { seedWorkspaceFiles } from '@/app/workspace/[workspaceId]/lib/seed-workspace-files'
 import {
   WORKSPACE_FILE_FOLDERS_STALE_TIME,
   workspaceFileFolderKeys,
@@ -15,14 +16,8 @@ import {
  * the Owner column — under the same query keys their client hooks (`useWorkspaceFileFolders`) use
  * (scope `active`), so the browser paints populated on first render.
  *
- * The FILE LIST itself is deliberately not here: the sidebar reads it on every workspace route, so
- * it is seeded by `prefetchWorkspaceSidebar` in the layout — the only boundary that renders
- * before the sidebar registers the query. Prefetching it again here would re-read it per request
- * and still not reach the server render (`HydrationBoundary` defers an already-seen query to an
- * effect, which SSR never runs). See the note on that entry. The layout declines to seed a
- * workspace whose file list exceeds its payload budget; recovering those here would mean
- * mirroring that budget check inversely, since an unconditional prefetch would re-read and
- * duplicate the entry for every workspace under the budget.
+ * The file list is seeded here rather than in the layout so only the routes that render it pay for
+ * it. See {@link seedWorkspaceFiles} for why a large workspace seeds nothing at all.
  *
  * Folders and the chrome reads all go through the data layer, shaped to their route contracts so a
  * hydrated entry matches a client fetch.
@@ -58,5 +53,6 @@ export async function prefetchFilesBrowser(
       staleTime: WORKSPACE_FILE_FOLDERS_STALE_TIME,
     }),
     prefetchResourceListChrome(queryClient, workspaceId, 'file', userId),
+    seedWorkspaceFiles(queryClient, workspaceId),
   ])
 }

apps/sim/app/workspace/[workspaceId]/home/page.tsx

@@ -1,8 +1,11 @@
 import { Suspense } from 'react'
+import { dehydrate, HydrationBoundary } from '@tanstack/react-query'
 import type { Metadata } from 'next'
 import { redirect } from 'next/navigation'
 import { getSession } from '@/lib/auth'
 import { isChatEnabled } from '@/lib/core/config/env-flags'
+import { getQueryClient } from '@/app/_shell/providers/get-query-client'
+import { prefetchHomeSurface } from '@/app/workspace/[workspaceId]/home/prefetch'
 import { resolveTableViewsEnabled } from '@/app/workspace/[workspaceId]/home/resolve-table-views-flag'
 import { Home } from './home'
 import { HomeFallback } from './home-fallback'
@@ -20,19 +23,23 @@ export default async function HomePage({ params }: { params: Promise<{ workspace
     redirect(`/workspace/${workspaceId}`)
   }
 
-  /**
-   * Home prefetches nothing of its own. Both lists it reads — workflow folders and
-   * the workspace file list — are hydrated by `prefetchWorkspaceSidebar` in the
-   * layout under the same keys, and re-reading them here would cost a second query
-   * per request without reaching the server render.
-   */
   const session = await getSession()
   const userId = session?.user?.id
-  const tableViewsEnabled = await resolveTableViewsEnabled(workspaceId, userId)
+  const queryClient = getQueryClient()
+  const [tableViewsEnabled] = await Promise.all([
+    resolveTableViewsEnabled(workspaceId, userId),
+    prefetchHomeSurface(queryClient, workspaceId, userId),
+  ])
 
   return (
-    <Suspense fallback={<HomeFallback />}>
-      <Home userName={session?.user?.name} userId={userId} tableViewsEnabled={tableViewsEnabled} />
-    </Suspense>
+    <HydrationBoundary state={dehydrate(queryClient)}>
+      <Suspense fallback={<HomeFallback />}>
+        <Home
+          userName={session?.user?.name}
+          userId={userId}
+          tableViewsEnabled={tableViewsEnabled}
+        />
+      </Suspense>
+    </HydrationBoundary>
   )
 }

apps/sim/app/workspace/[workspaceId]/home/prefetch.ts

@@ -0,0 +1,27 @@
+import type { QueryClient } from '@tanstack/react-query'
+import { getWorkspaceHostContextForViewer } from '@/lib/workspaces/host-context'
+import { seedWorkspaceFiles } from '@/app/workspace/[workspaceId]/lib/seed-workspace-files'
+
+/**
+ * Prefetches what the Home surface needs on top of the workspace layout's own prefetch.
+ *
+ * Home reads the workspace file list on mount (resource tabs, mentions, the resource picker), so
+ * the list is seeded by the routes that render Home rather than by the layout: seeding it in the
+ * layout would pay for it on every workspace route, including the ones that never read it.
+ *
+ * The seed carries no authorization of its own, so the viewer is proved first. This reuses the
+ * layout's `cache`d host-context lookup rather than re-deriving the permission, so it costs no
+ * additional queries; a viewer without access caches nothing and the client fetch reaches the
+ * route for the real 403.
+ */
+export async function prefetchHomeSurface(
+  queryClient: QueryClient,
+  workspaceId: string,
+  userId: string | undefined
+): Promise<void> {
+  if (!userId) return
+  const hostContext = await getWorkspaceHostContextForViewer(workspaceId, userId)
+  if (!hostContext) return
+
+  await seedWorkspaceFiles(queryClient, workspaceId)
+}

apps/sim/app/workspace/[workspaceId]/lib/prefetch.test.ts

@@ -97,10 +97,7 @@ vi.mock('@sim/emcn', () => ({
 
 import { prefetchFilesBrowser } from '@/app/workspace/[workspaceId]/files/prefetch'
 import { prefetchKnowledgeBases } from '@/app/workspace/[workspaceId]/knowledge/prefetch'
-import {
-  prefetchWorkspaceSidebar,
-  WORKSPACE_FILE_SEED_MAX,
-} from '@/app/workspace/[workspaceId]/prefetch'
+import { prefetchWorkspaceSidebar } from '@/app/workspace/[workspaceId]/prefetch'
 import { prefetchTables } from '@/app/workspace/[workspaceId]/tables/prefetch'
 import { folderKeys } from '@/hooks/queries/utils/folder-keys'
 import { knowledgeKeys } from '@/hooks/queries/utils/knowledge-keys'
@@ -357,19 +354,18 @@ describe('workspace list prefetches', () => {
     })
 
     /**
-     * The FILE LIST is deliberately not primed here — `prefetchWorkspaceSidebar` owns it, because the
-     * sidebar reads that query on every workspace route and therefore registers it before any page
-     * renders. `HydrationBoundary` hands an already-seen query to a `useEffect`, which SSR never runs,
-     * so a page-level prefetch of this key costs a request per render and still cannot reach the server
-     * render. Restoring it here would reintroduce exactly that.
+     * The file list is the browser's primary content, so it must be seeded by the page that
+     * renders it — the layout no longer seeds it, which would have charged every workspace
+     * route for a list only a few of them read.
      */
-    it('leaves the file list to the layout rather than re-reading it per page', async () => {
+    it('seeds the file list the browser renders', async () => {
+      const files = [{ id: 'file-1' }]
+      mockListWorkspaceFilesWithShares.mockResolvedValue(files)
       const client = makeClient()
 
       await prefetchFilesBrowser(client, WORKSPACE_ID, USER_ID)
 
-      expect(mockListWorkspaceFilesWithShares).not.toHaveBeenCalled()
-      expect(client.getQueryData(workspaceFilesKeys.list(WORKSPACE_ID, 'active'))).toBeUndefined()
+      expect(client.getQueryData(workspaceFilesKeys.list(WORKSPACE_ID, 'active'))).toEqual(files)
     })
 
     /**
@@ -514,48 +510,15 @@ describe('workspace list prefetches', () => {
     })
 
     /**
-     * The file list is seeded on every workspace route, so it is the one entry whose size
-     * scales with a workspace's content on routes that never read it. The budget is passed
-     * down rather than applied here, so the read can stop before the share join.
-     */
-    it('seeds the file list, bounded by the document payload budget', async () => {
-      const files = [{ id: 'file-1', name: 'a.txt' }]
-      mockListWorkspaceFilesWithShares.mockResolvedValue(files)
-      const client = makeClient()
-
-      await prefetchWorkspaceSidebar(client, WORKSPACE_ID, USER_ID, HOST_CONTEXT, null)
-
-      expect(mockListWorkspaceFilesWithShares).toHaveBeenCalledWith(WORKSPACE_ID, 'active', {
-        maxRows: WORKSPACE_FILE_SEED_MAX,
-        /** A failed read must reach the catch, not degrade to a cached empty list. */
-        throwOnError: true,
-      })
-      expect(client.getQueryData(workspaceFilesKeys.list(WORKSPACE_ID, 'active'))).toEqual(files)
-    })
-
-    /**
-     * The load-bearing half of the budget: a workspace over it seeds NOTHING rather than the
-     * prefix that was read. The sidebar search filters this list client-side and the Files
-     * browser renders it as the workspace's files, so a truncated seed would silently hide
-     * files — the client fetch must reach the route for the complete list instead.
+     * The file list belongs to the pages that render it, not to every workspace route. A sidebar
+     * seed would charge the workflow editor, logs, and settings for a read none of them make.
      */
-    it('seeds nothing when the workspace exceeds the budget', async () => {
-      mockListWorkspaceFilesWithShares.mockResolvedValue(null)
+    it('does not read the workspace file list', async () => {
       const client = makeClient()
 
       await prefetchWorkspaceSidebar(client, WORKSPACE_ID, USER_ID, HOST_CONTEXT, null)
 
-      expect(client.getQueryData(workspaceFilesKeys.list(WORKSPACE_ID, 'active'))).toBeUndefined()
-    })
-
-    /** A failed file read is an optimization loss, not a render failure. */
-    it('does not throw when the file read rejects, and seeds no files', async () => {
-      mockListWorkspaceFilesWithShares.mockRejectedValue(new Error('500'))
-      const client = makeClient()
-
-      await expect(
-        prefetchWorkspaceSidebar(client, WORKSPACE_ID, USER_ID, HOST_CONTEXT, null)
-      ).resolves.toBeUndefined()
+      expect(mockListWorkspaceFilesWithShares).not.toHaveBeenCalled()
       expect(client.getQueryData(workspaceFilesKeys.list(WORKSPACE_ID, 'active'))).toBeUndefined()
     })
 
@@ -591,9 +554,9 @@ describe('workspace list prefetches', () => {
       ],
       [
         /**
-         * Asserted against the folder key, not the file list: `prefetchFilesBrowser`
-         * deliberately never seeds `workspaceFilesKeys` (the layout owns it), so an
-         * assertion on that key would hold no matter what this function did.
+         * Asserted against the folder key: the file list is seeded rather than prefetched, so
+         * a rejecting read leaves that key empty by design and could not distinguish a
+         * swallowed failure from a function that did nothing.
          */
         'prefetchFilesBrowser',
         (client: QueryClient) => prefetchFilesBrowser(client, WORKSPACE_ID, USER_ID),

apps/sim/app/workspace/[workspaceId]/lib/seed-workspace-files.test.ts

@@ -0,0 +1,80 @@
+/**
+ * @vitest-environment node
+ */
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { mockListWorkspaceFilesWithShares } = vi.hoisted(() => ({
+  mockListWorkspaceFilesWithShares: vi.fn(),
+}))
+
+vi.mock('@/lib/workspace-files/queries', () => ({
+  listWorkspaceFilesWithShares: mockListWorkspaceFilesWithShares,
+}))
+
+/** The key factory lives in a `'use client'` module that pulls emcn's CSS at import. */
+vi.mock('@sim/emcn', () => ({
+  toast: { success: vi.fn(), error: vi.fn() },
+}))
+
+import {
+  seedWorkspaceFiles,
+  WORKSPACE_FILE_SEED_MAX,
+} from '@/app/workspace/[workspaceId]/lib/seed-workspace-files'
+import { workspaceFilesKeys } from '@/hooks/queries/workspace-files'
+
+const WORKSPACE_ID = 'ws-123'
+
+function makeClient() {
+  const store = new Map<string, unknown>()
+  return {
+    setQueryData: (key: readonly unknown[], value: unknown) =>
+      store.set(JSON.stringify(key), value),
+    getQueryData: (key: readonly unknown[]) => store.get(JSON.stringify(key)),
+  } as never as import('@tanstack/react-query').QueryClient & {
+    getQueryData: (key: readonly unknown[]) => unknown
+  }
+}
+
+describe('seedWorkspaceFiles', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('seeds the file list, bounded by the document payload budget', async () => {
+    const files = [{ id: 'file-1', name: 'a.txt' }]
+    mockListWorkspaceFilesWithShares.mockResolvedValue(files)
+    const client = makeClient()
+
+    await seedWorkspaceFiles(client, WORKSPACE_ID)
+
+    expect(mockListWorkspaceFilesWithShares).toHaveBeenCalledWith(WORKSPACE_ID, 'active', {
+      maxRows: WORKSPACE_FILE_SEED_MAX,
+      /** A failed read must reach the catch, not degrade to a cached empty list. */
+      throwOnError: true,
+    })
+    expect(client.getQueryData(workspaceFilesKeys.list(WORKSPACE_ID, 'active'))).toEqual(files)
+  })
+
+  /**
+   * A workspace over the budget seeds NOTHING rather than the prefix that was read: the
+   * Files browser renders this list as the workspace's files, so a truncated seed would
+   * silently hide some. The client fetch reaches the route for the complete list instead.
+   */
+  it('seeds nothing when the workspace exceeds the budget', async () => {
+    mockListWorkspaceFilesWithShares.mockResolvedValue(null)
+    const client = makeClient()
+
+    await seedWorkspaceFiles(client, WORKSPACE_ID)
+
+    expect(client.getQueryData(workspaceFilesKeys.list(WORKSPACE_ID, 'active'))).toBeUndefined()
+  })
+
+  /** A failed read is an optimization loss, not a render failure. */
+  it('does not throw when the read rejects, and seeds nothing', async () => {
+    mockListWorkspaceFilesWithShares.mockRejectedValue(new Error('500'))
+    const client = makeClient()
+
+    await expect(seedWorkspaceFiles(client, WORKSPACE_ID)).resolves.toBeUndefined()
+    expect(client.getQueryData(workspaceFilesKeys.list(WORKSPACE_ID, 'active'))).toBeUndefined()
+  })
+})

apps/sim/app/workspace/[workspaceId]/lib/seed-workspace-files.ts

@@ -0,0 +1,48 @@
+import { createLogger } from '@sim/logger'
+import { getErrorMessage } from '@sim/utils/errors'
+import type { QueryClient } from '@tanstack/react-query'
+import { listWorkspaceFilesWithShares } from '@/lib/workspace-files/queries'
+import { workspaceFilesKeys } from '@/hooks/queries/workspace-files'
+
+const logger = createLogger('SeedWorkspaceFiles')
+
+/**
+ * How many files a page is willing to inline into its document. At ~500 bytes of JSON per
+ * file this budgets the entry at ~150 KB.
+ *
+ * A workspace above the budget seeds NOTHING rather than a prefix: the Files browser
+ * renders this list as the workspace's files, so a truncated seed would silently hide some.
+ */
+export const WORKSPACE_FILE_SEED_MAX = 300
+
+/**
+ * Seeds the workspace's file list for the pages that render it.
+ *
+ * Seeded rather than prefetched so it can decline to create an entry at all above
+ * {@link WORKSPACE_FILE_SEED_MAX} — `prefetchQuery` always creates one, and a partial
+ * entry would be read as the whole list. Parsed through the route's response contract, so
+ * a seeded entry matches what a client fetch caches.
+ */
+export async function seedWorkspaceFiles(
+  queryClient: QueryClient,
+  workspaceId: string
+): Promise<void> {
+  try {
+    const files = await listWorkspaceFilesWithShares(workspaceId, 'active', {
+      maxRows: WORKSPACE_FILE_SEED_MAX,
+      /**
+       * A failed read must reach the catch below, not degrade to an empty list: seeding
+       * `[]` would cache "this workspace has no files" as authoritative for the entry's
+       * lifetime, which is worse than seeding nothing and letting the client fetch.
+       */
+      throwOnError: true,
+    })
+    if (!files) return
+    queryClient.setQueryData(workspaceFilesKeys.list(workspaceId, 'active'), files)
+  } catch (error) {
+    /** Optimization only: the client fetch reaches the route instead. */
+    logger.warn('Workspace file list seed failed; client will fetch', {
+      error: getErrorMessage(error),
+    })
+  }
+}