@@ -19,8 +19,8 @@ import {
 import type { ChatResource } from '@/lib/copilot/resources/persistence'
 import {
   canonicalizeDesktopSessionResource,
-  canonicalizeDesktopSessionResources,
   GENERIC_RESOURCE_TITLES,
+  sanitizeChatResources,
 } from '@/lib/copilot/resources/types'
 import { withRouteHandler } from '@/lib/core/utils/with-route-handler'
 
@@ -67,7 +67,7 @@ export const POST = withRouteHandler(async (req: NextRequest) => {
       return createNotFoundResponse('Chat not found or unauthorized')
     }
 
-    const existing = canonicalizeDesktopSessionResources(
+    const existing = sanitizeChatResources(
       Array.isArray(chat.resources) ? (chat.resources as ChatResource[]) : []
     )
     const key = `${resource.type}:${resource.id}`
@@ -141,10 +141,10 @@ export const PATCH = withRouteHandler(async (req: NextRequest) => {
       return createNotFoundResponse('Chat not found or unauthorized')
     }
 
-    const existing = canonicalizeDesktopSessionResources(
+    const existing = sanitizeChatResources(
       Array.isArray(chat.resources) ? (chat.resources as ChatResource[]) : []
     )
-    const canonicalOrder = canonicalizeDesktopSessionResources(newOrder)
+    const canonicalOrder = sanitizeChatResources(newOrder)
     const existingKeys = new Set(existing.map((r) => `${r.type}:${r.id}`))
     const newKeys = new Set(canonicalOrder.map((r) => `${r.type}:${r.id}`))
 
 
@@ -29,10 +29,7 @@ import {
   createUnauthorizedResponse,
 } from '@/lib/copilot/request/http'
 import { removeChatResources } from '@/lib/copilot/resources/persistence'
-import {
-  canonicalizeDesktopSessionResources,
-  type MothershipResource,
-} from '@/lib/copilot/resources/types'
+import { type MothershipResource, sanitizeChatResources } from '@/lib/copilot/resources/types'
 import { getMothershipBaseURL, getMothershipSourceEnvHeaders } from '@/lib/copilot/server/agent-url'
 import { env } from '@/lib/core/config/env'
 import { withRouteHandler } from '@/lib/core/utils/with-route-handler'
@@ -118,7 +115,7 @@ export const POST = withRouteHandler(
       // file resources whose chat-owned file is NOT copied (uploads born
       // after the cut) are dropped in the rewrite below; everything else is
       // copied.
-      const parentResources = canonicalizeDesktopSessionResources(
+      const parentResources = sanitizeChatResources(
         Array.isArray(parent.resources) ? (parent.resources as MothershipResource[]) : []
       )
 
 
@@ -10,7 +10,7 @@ import {
   useRef,
 } from 'react'
 import { noop } from '@sim/utils/helpers'
-import type { MothershipResource } from '@/app/workspace/[workspaceId]/home/types'
+import type { WorkspaceResourceRef } from '@/app/workspace/[workspaceId]/home/types'
 import type { ChatContext } from '@/stores/panel'
 
 /**
@@ -34,7 +34,7 @@ interface ChatSurfaceContextValue {
    */
   onContextRemove: (context: ChatContext, remaining: ChatContext[]) => void
   /** Opens a workspace resource referenced from rendered message content. */
-  onWorkspaceResourceSelect: (resource: MothershipResource) => void
+  onWorkspaceResourceSelect: (resource: WorkspaceResourceRef) => void
 }
 
 const ChatSurfaceContext = createContext<ChatSurfaceContextValue>({
@@ -48,7 +48,7 @@ interface ChatSurfaceProviderProps {
   userId?: string
   onContextAdd?: (context: ChatContext) => void
   onContextRemove?: (context: ChatContext, remaining: ChatContext[]) => void
-  onWorkspaceResourceSelect?: (resource: MothershipResource) => void
+  onWorkspaceResourceSelect?: (resource: WorkspaceResourceRef) => void
   children: ReactNode
 }
 
@@ -82,7 +82,7 @@ export function ChatSurfaceProvider({
   const stableOnContextRemove = useCallback((context: ChatContext, remaining: ChatContext[]) => {
     onContextRemoveRef.current?.(context, remaining)
   }, [])
-  const stableOnWorkspaceResourceSelect = useCallback((resource: MothershipResource) => {
+  const stableOnWorkspaceResourceSelect = useCallback((resource: WorkspaceResourceRef) => {
     onWorkspaceResourceSelectRef.current?.(resource)
   }, [])
 
 
@@ -20,7 +20,10 @@ import {
   parseSpecialTags,
   SpecialTags,
 } from '@/app/workspace/[workspaceId]/home/components/message-content/components/special-tags'
-import type { ChatContextKind, MothershipResource } from '@/app/workspace/[workspaceId]/home/types'
+import type {
+  ChatContextKind,
+  WorkspaceResourceRef,
+} from '@/app/workspace/[workspaceId]/home/types'
 import { useSmoothText } from '@/hooks/use-smooth-text'
 import { sanitizeChatDisplayContent } from './chat-sanitize'
 import { ExternalLink, externalLinkHostname } from './external-link'
@@ -278,6 +281,9 @@ const MARKDOWN_COMPONENTS = {
             e.preventDefault()
             if (!type || !ref) return
             const linkText = label || ref
+            // A file link carries whichever the tag had (`path ?? id`) with no
+            // way to tell them apart here, so it is forwarded as-is and the
+            // resolver tries every interpretation against the real file list.
             window.dispatchEvent(
               new CustomEvent('wsres-click', {
                 detail:
@@ -393,7 +399,7 @@ interface ChatContentProps {
   questionAnswers?: string[]
   onOptionSelect?: (id: string) => void
   onQuestionDismiss?: () => void
-  onWorkspaceResourceSelect?: (resource: MothershipResource) => void
+  onWorkspaceResourceSelect?: (resource: WorkspaceResourceRef) => void
   onRevealStateChange?: (isRevealing: boolean) => void
   /** Reports whether this segment is actively painting text. */
   onStreamActivityChange?: (active: boolean) => void
@@ -520,10 +526,12 @@ function ChatContentInner({
   useEffect(() => {
     const handler = (e: Event) => {
       const { type, id, path, title } = (e as CustomEvent).detail
+      // A link built from a path carries no id. Forward what the tag actually
+      // had; the select handler resolves it rather than guessing here.
       onWorkspaceResourceSelectRef.current?.({
         type,
-        id: id ?? '',
-        path,
+        ...(id ? { id } : {}),
+        ...(path ? { path } : {}),
         title: title || id || path || '',
       })
     }
 
@@ -21,7 +21,6 @@ import { useSession } from '@/lib/auth/auth-client'
 import { buildHostedUpgradeUrl, HOSTED_BILLING_SETTINGS_URL } from '@/lib/billing/upgrade-reasons'
 import { canManageWorkspaceBilling } from '@/lib/billing/workspace-permissions'
 import { isBrowserAgentAvailable, sendBrowserPanelAction } from '@/lib/browser-agent/transport'
-import { canonicalWorkspaceFilePath } from '@/lib/copilot/vfs/path-utils'
 import { isHosted } from '@/lib/core/config/env-flags'
 import { isSafeHttpUrl } from '@/lib/core/utils/urls'
 import { getDesktopBridge } from '@/lib/desktop'
@@ -39,6 +38,7 @@ import { QuestionDisplay } from '@/app/workspace/[workspaceId]/home/components/m
 import type {
   ChatMessageContext,
   MothershipResource,
+  WorkspaceResourceRef,
 } from '@/app/workspace/[workspaceId]/home/types'
 // Deep import, not the barrel: the barrel also re-exports
 // ConnectServiceAccountModal, and that edge would pull the modal into this
@@ -54,6 +54,7 @@ import {
 } from '@/hooks/queries/environment'
 import { useKnowledgeBasesQuery } from '@/hooks/queries/kb/knowledge'
 import { useTablesList } from '@/hooks/queries/tables'
+import { findWorkspaceFileByPath } from '@/hooks/queries/utils/find-workspace-file-by-src'
 import { useWorkflows } from '@/hooks/queries/workflows'
 import { useWorkspaceFiles } from '@/hooks/queries/workspace-files'
 import { useSettingsNavigation } from '@/hooks/use-settings-navigation'
@@ -1300,7 +1301,7 @@ interface SpecialTagsProps {
   questionAnswers?: string[]
   onOptionSelect?: (id: string) => void
   onQuestionDismiss?: () => void
-  onWorkspaceResourceSelect?: (resource: MothershipResource) => void
+  onWorkspaceResourceSelect?: (resource: WorkspaceResourceRef) => void
 }
 
 /**
@@ -1455,23 +1456,17 @@ export function WorkspaceResourceDisplay({
   onSelect,
 }: {
   data: WorkspaceResourceTagData
-  onSelect?: (resource: MothershipResource) => void
+  onSelect?: (resource: WorkspaceResourceRef) => void
 }) {
   const { workspaceId } = useParams<{ workspaceId: string }>()
   const { data: workflows = [] } = useWorkflows(workspaceId)
   const { data: tables = [] } = useTablesList(workspaceId)
   const { data: files = [] } = useWorkspaceFiles(workspaceId)
   const { data: knowledgeBases = [] } = useKnowledgeBasesQuery(workspaceId)
 
-  const resource = useMemo<MothershipResource>(() => {
+  const resource = useMemo<WorkspaceResourceRef>(() => {
     const fileFromPath =
-      data.type === 'file' && data.path
-        ? files.find(
-            (file) =>
-              canonicalWorkspaceFilePath({ folderPath: file.folderPath, name: file.name }) ===
-              data.path
-          )
-        : undefined
+      data.type === 'file' ? findWorkspaceFileByPath(files, data.path) : undefined
     const title =
       data.type === 'workflow'
         ? (workflows.find((workflow) => workflow.id === data.id)?.name ??
@@ -1487,9 +1482,10 @@ export function WorkspaceResourceDisplay({
             : (knowledgeBases.find((knowledgeBase) => knowledgeBase.id === data.id)?.name ??
               fallbackWorkspaceResourceTitle(data.type))
 
+    const id = data.id ?? fileFromPath?.id
     return {
       type: toMothershipResourceType(data.type),
-      id: data.id ?? fileFromPath?.id ?? data.path ?? '',
+      ...(id ? { id } : {}),
       title,
       ...(data.type === 'file' && data.path ? { path: data.path } : {}),
     }
 
@@ -35,8 +35,8 @@ import type {
   ChatMessageContext,
   ContentBlock,
   FileAttachmentForApi,
-  MothershipResource,
   QueuedMessage,
+  WorkspaceResourceRef,
 } from '@/app/workspace/[workspaceId]/home/types'
 import { useAutoScroll } from '@/hooks/use-auto-scroll'
 import type { ChatContext } from '@/stores/panel'
@@ -70,7 +70,7 @@ interface MothershipChatProps {
    * `ChatSurfaceContextValue`, which this forwards to.
    */
   onContextRemove?: (context: ChatContext, remaining: ChatContext[]) => void
-  onWorkspaceResourceSelect?: (resource: MothershipResource) => void
+  onWorkspaceResourceSelect?: (resource: WorkspaceResourceRef) => void
   draftScopeKey?: string
   layout?: 'mothership-view' | 'copilot-view'
   initialScrollBlocked?: boolean
 
@@ -12,15 +12,15 @@ import {
   useState,
   useSyncExternalStore,
 } from 'react'
-import { Button, cn } from '@sim/emcn'
+import { Button, cn, toast } from '@sim/emcn'
 import { PanelLeft } from '@sim/emcn/icons'
 import { createLogger } from '@sim/logger'
+import { useQueryClient } from '@tanstack/react-query'
 import { useParams, useRouter } from 'next/navigation'
 import { useQueryState } from 'nuqs'
 import { usePostHog } from 'posthog-js/react'
 import { requestJson } from '@/lib/api/client/request'
 import { createWorkflowContract } from '@/lib/api/contracts'
-import { canonicalWorkspaceFilePath } from '@/lib/copilot/vfs/path-utils'
 import {
   LandingPromptStorage,
   type LandingWorkflowSeed,
@@ -36,14 +36,15 @@ import {
 import { captureEvent } from '@/lib/posthog/client'
 import { persistImportedWorkflow } from '@/lib/workflows/operations/import-export'
 import { RESOURCE_HEADER_CLASSES } from '@/app/workspace/[workspaceId]/home/components/mothership-view/components/resource-tabs/resource-tab-controls'
+import { resolveWorkspaceResourceRef } from '@/app/workspace/[workspaceId]/home/resolve-resource-ref'
 import { resourceParam, resourceUrlKeys } from '@/app/workspace/[workspaceId]/home/search-params'
 import { useFolders } from '@/hooks/queries/folders'
 import {
   useMarkMothershipChatRead,
   useMothershipChatHistory,
 } from '@/hooks/queries/mothership-chats'
 import { useWorkflows } from '@/hooks/queries/workflows'
-import { useWorkspaceFiles } from '@/hooks/queries/workspace-files'
+import { getWorkspaceFilesQueryOptions, useWorkspaceFiles } from '@/hooks/queries/workspace-files'
 import { useOAuthReturnRouter } from '@/hooks/use-oauth-return'
 import type { ChatContext } from '@/stores/panel'
 import {
@@ -56,7 +57,12 @@ import {
   type UserInputHandle,
 } from './components'
 import { getMothershipUseChatOptions, useChat, useMothershipResize } from './hooks'
-import type { FileAttachmentForApi, MothershipResource, MothershipResourceType } from './types'
+import type {
+  FileAttachmentForApi,
+  MothershipResource,
+  MothershipResourceType,
+  WorkspaceResourceRef,
+} from './types'
 
 const logger = createLogger('Home')
 const subscribeToDesktopApp = () => () => {}
@@ -90,6 +96,7 @@ export function Home({ chatId, userName, userId, tableViewsEnabled }: HomeProps)
   )
   const { workspaceId } = useParams<{ workspaceId: string }>()
   const router = useRouter()
+  const queryClient = useQueryClient()
   /**
    * URL is the single source of truth for the selected resource. `Home` renders
    * client-side, so nuqs reads `?resource=` from the URL on mount — the same
@@ -432,39 +439,56 @@ export function Home({ chatId, userName, userId, tableViewsEnabled }: HomeProps)
     removeResource(resolved.type, resolved.id)
   }
 
-  const resolveFileResource = useCallback(
-    (resource: MothershipResource): MothershipResource => {
-      if (resource.type !== 'file') return resource
-
-      const reference = (resource.path || resource.id).trim()
-
-      const file = workspaceFiles.find((candidate) => {
-        const candidatePath = canonicalWorkspaceFilePath({
-          folderPath: candidate.folderPath,
-          name: candidate.name,
-        })
-        return candidate.id === reference || candidatePath === reference
-      })
-
-      if (!file) return resource
-      return {
-        ...resource,
-        id: file.id,
-        title: resource.title || file.name,
-      }
-    },
-    [workspaceFiles]
-  )
-
-  function handleWorkspaceResourceSelect(resource: MothershipResource) {
-    const resolvedResource = resolveFileResource(resource)
-    const wasAdded = addResource(resolvedResource)
+  function openWorkspaceResource(resource: MothershipResource) {
+    const wasAdded = addResource(resource)
     if (!wasAdded) {
-      setActiveResourceId(resolvedResource.id)
+      setActiveResourceId(resource.id)
     }
     handleResourceEvent()
   }
 
+  /**
+   * Opens the resource a message chip points at, resolving it first. A chip may
+   * carry only a filename — the agent names a file before the client's file
+   * list knows it exists — so one forced refetch closes that window. What still
+   * resolves to nothing opens nothing, rather than a tab that cannot be
+   * viewed or removed.
+   */
+  async function handleWorkspaceResourceSelect(ref: WorkspaceResourceRef) {
+    const immediate = resolveWorkspaceResourceRef(ref, workspaceFiles)
+    if (immediate) {
+      openWorkspaceResource(immediate)
+      return
+    }
+    if (ref.type !== 'file') return
+
+    // `staleTime: 0` forces the fetch this branch exists for — the cached list
+    // is what already failed to resolve. `fetchQuery` rejects on error and this
+    // handler is invoked as a void callback, so failure becomes null rather
+    // than an unhandled rejection — and stays distinct from an empty list, so
+    // "we could not look" is never reported as "it is not there".
+    const files = await queryClient
+      .fetchQuery({ ...getWorkspaceFilesQueryOptions(workspaceId), staleTime: 0 })
+      .catch(() => null)
+    const resolved = files && resolveWorkspaceResourceRef(ref, files)
+    if (resolved) {
+      openWorkspaceResource(resolved)
+      return
+    }
+    // The chip looks clickable, so refusing silently reads as a broken button.
+    toast.error(
+      files
+        ? `Couldn't find "${ref.title}" in this workspace`
+        : `Couldn't open "${ref.title}" — check your connection and try again`
+    )
+    logger.warn('Ignored a resource chip that did not resolve', {
+      type: ref.type,
+      title: ref.title,
+      hasPath: Boolean(ref.path),
+      reachedWorkspace: files !== null,
+    })
+  }
+
   const hasMessages = messages.length > 0
   const showChatSkeleton = Boolean(chatId) && !hasMessages && isChatHistoryPending
   const draftScopeKey = `${workspaceId}:${chatId ?? 'new'}`