refactor(chat): clean up highlight-to-chat selections

Correctness:
- Stop reporting fabricated line numbers for rich-markdown selections.
  `doc.textBetween` counts ProseMirror block boundaries, not markdown source
  lines, so the chip label and the agent prompt both claimed line ranges that
  don't exist in the file. Line info is now emitted only by Monaco.
- Bound a table_selection's rendered markdown by characters, not just row and
  column counts — 500 wide rows dwarfed the 20k-char file-selection budget.
  Rows are emitted until the budget is spent, and the content says what was
  omitted.
- Complete `areContextsEqual` for both selection kinds, so re-adding the same
  selection dedupes while a different passage of an already-referenced file
  registers as new.

Consistency:
- Carry the resource display name on the context instead of recovering it by
  regex from the chip label, deleting fileNameFromSelectionLabel and
  tableNameFromSelectionLabel.
- Replace the user-visible `#k3f9` hash disambiguator with a readable ordinal
  applied at insert time (`Sales (3 rows) (2)`), via a shared
  prepareContextForInsert used by both the add-to-chat and paste paths.
- Fold MothershipPendingContextStorage into MothershipHandoffStorage as a
  chip-only handoff (optional message), removing the parallel storage class,
  the second drain effect, and its StrictMode guard ref.
- Replace `window.location.assign` with `router.push`, matching the existing
  "Troubleshoot in Chat" handoff.
- Collapse three near-duplicate synchronous copy branches in table-grid into
  shared buildTableSelectionContext / writeLoadedRowsWithChip helpers, also
  reused by the add-to-chat handler.
- Trim multi-paragraph inline comments to TSDoc stating each reason once.

Tests: new coverage for the character budget, the label ordinal, selection
equality, and chip-only handoff accumulation; each verified to fail when its
fix is reverted.

Author: waleedlatif1

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/rich-markdown-editor.tsx

@@ -14,7 +14,6 @@ import { useRouter } from 'next/navigation'
 import { useSession } from '@/lib/auth/auth-client'
 import {
   buildFileSelectionLabel,
-  selectionKey,
   truncateSelectionText,
 } from '@/lib/copilot/chat/selection-context'
 import type { WorkspaceFileRecord } from '@/lib/uploads/contexts/workspace'
@@ -1133,23 +1132,25 @@ export function LoadedRichMarkdownEditor({
   )
 
   const addToChat = useAddToChat()
+  /**
+   * No line range: this editor renders a ProseMirror document, whose block
+   * boundaries do not correspond to markdown source lines (blank lines between
+   * paragraphs, list markers, heading prefixes and fenced blocks all shift the
+   * real line). Reporting a derived count would label the chip — and prompt the
+   * agent — with line numbers that don't exist in the file.
+   */
   const buildSelectionContext = useCallback((): ChatContext | null => {
     if (!editor) return null
     const { from, to } = editor.state.selection
     if (from === to) return null
     const text = editor.state.doc.textBetween(from, to, '\n')
     if (!text.trim()) return null
-    // Markdown has no native line numbers; approximate from newlines before the
-    // selection so repeated selections in the same file get distinct labels.
-    const startLine = editor.state.doc.textBetween(0, from, '\n').split('\n').length
-    const endLine = startLine + text.split('\n').length - 1
     return {
       kind: 'file_selection',
       fileId: file.id,
-      label: buildFileSelectionLabel(file.name, startLine, endLine, selectionKey([text])),
+      fileName: file.name,
+      label: buildFileSelectionLabel(file.name),
       text: truncateSelectionText(text),
-      startLine,
-      endLine,
     }
   }, [editor, file.id, file.name])
 

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/text-editor.tsx

@@ -7,7 +7,6 @@ import type { editor as MonacoEditorTypes } from 'monaco-editor'
 import dynamic from 'next/dynamic'
 import {
   buildFileSelectionLabel,
-  selectionKey,
   truncateSelectionText,
 } from '@/lib/copilot/chat/selection-context'
 import type { WorkspaceFileRecord } from '@/lib/uploads/contexts/workspace'
@@ -395,7 +394,8 @@ export const TextEditor = memo(function TextEditor({
     return {
       kind: 'file_selection',
       fileId: file.id,
-      label: buildFileSelectionLabel(file.name, startLine, endLine, selectionKey([text])),
+      fileName: file.name,
+      label: buildFileSelectionLabel(file.name, startLine, endLine),
       text: truncateSelectionText(text),
       startLine,
       endLine,

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/use-selection-copy-bridge.ts

@@ -8,15 +8,14 @@ import type { ChatContext } from '@/stores/panel'
  * Rides a selection {@link ChatContext} onto the editor's native copy so a
  * highlighted passage copied with Cmd+C pastes into Chat as a reference chip.
  *
- * The listener is attached to `containerRef` in the BUBBLE phase so it runs
- * AFTER the inner editor's own copy handler (Monaco and ProseMirror both call
- * `clearData()` then write `text/plain`/`text/html`) — the custom
- * `text/x-sim-selection` type is added last and survives, leaving normal copy
- * untouched. `buildContext` returns `null` when there is no non-empty selection.
+ * Attached in the BUBBLE phase so it runs after the inner editor's own copy
+ * handler — Monaco and ProseMirror both `clearData()` before writing
+ * `text/plain`, so the custom type must be added last to survive.
  *
- * `enabled` lets a caller whose container mounts late (e.g. behind a loading
- * gate) re-run the effect once the node exists — a ref object isn't reactive, so
- * without it the effect would bail on the first render and never re-attach.
+ * @param buildContext - Returns null when there is no non-empty selection.
+ * @param enabled - Re-runs the effect for a container that mounts late (behind a
+ * loading gate); a ref isn't reactive, so the effect would otherwise bail on the
+ * first render and never re-attach.
  */
 export function useSelectionCopyBridge(
   containerRef: RefObject<HTMLElement | null>,

apps/sim/app/workspace/[workspaceId]/home/components/chat-context-kind-registry/chat-context-kind-registry.tsx

@@ -12,7 +12,6 @@ import {
 } from '@sim/emcn/icons'
 import { AgentSkillsIcon, McpIcon } from '@/components/icons'
 import { getDocumentIcon } from '@/components/icons/document-icons'
-import { fileNameFromSelectionLabel } from '@/lib/copilot/chat/selection-context'
 import type { ChatContextKind, ChatMessageContext } from '@/app/workspace/[workspaceId]/home/types'
 import { getBareIconStyle } from '@/blocks/brand-icon-style'
 import { getBlockRegistry } from '@/blocks/registry'
@@ -90,9 +89,9 @@ export const CHAT_CONTEXT_KIND_REGISTRY: Record<ChatContextKind, ChatContextKind
   file_selection: {
     label: 'File selection',
     renderIcon: ({ context, className }) => {
-      // Strip the `:line` suffix so `getDocumentIcon` reads the real extension
-      // (e.g. `md`, not `md:12-40`) and shows the correct file glyph.
-      const FileDocIcon = getDocumentIcon('', fileNameFromSelectionLabel(context.label))
+      // The label carries a `:line` suffix, so read the extension off the file
+      // name the context carries — `getDocumentIcon` needs `md`, not `md:12-40`.
+      const FileDocIcon = getDocumentIcon('', context.fileName ?? context.label)
       return <FileDocIcon className={className} />
     },
   },

apps/sim/app/workspace/[workspaceId]/home/components/user-input/components/chip-clipboard-codec.ts

@@ -162,11 +162,11 @@ export function serializeSelectionForClipboard(
 
 /**
  * Finds the selection-scoped chips (`file_selection` / `table_selection`) whose
- * highlighted token falls inside `selectedText`. These kinds carry an inline
- * text blob / row-id array that can't fit a portable `sim:kind/id` link, so the
- * chat input's copy/cut path round-trips them through the custom
- * `text/x-sim-selection` clipboard MIME instead. Uses the overlay's exact
- * tokenization so a label that is a substring of another never false-matches.
+ * highlighted token falls inside `selectedText` — the chips the copy/cut path
+ * must route through the custom clipboard MIME rather than a portable link.
+ *
+ * Uses the overlay's exact tokenization so a label that is a substring of
+ * another never false-matches.
  */
 export function selectionContextsInText(
   selectedText: string,

apps/sim/app/workspace/[workspaceId]/home/components/user-input/components/prompt-editor/use-prompt-editor.ts

@@ -25,7 +25,7 @@ import {
   useMentionTokens,
 } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/user-input/hooks'
 import {
-  isContextAlreadySelected,
+  prepareContextForInsert,
   restoreSkillTriggerText,
   SKILL_CHIP_TRIGGER,
 } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/copilot/components/user-input/utils'
@@ -475,10 +475,11 @@ export function usePromptEditor({
    */
   const insertContextChip = useCallback(
     (context: ChatContext) => {
-      // A chip's `@label` token must be unique — `addContext` dedupes a matching
-      // label, so inserting a token for an already-present context would orphan
-      // it (a second token with no backing context). Skip and just focus.
-      if (isContextAlreadySelected(context, contextManagementRef.current.selectedContexts)) {
+      const prepared = prepareContextForInsert(
+        context,
+        contextManagementRef.current.selectedContexts
+      )
+      if (!prepared) {
         textareaRef.current?.focus()
         return
       }
@@ -487,16 +488,15 @@ export function usePromptEditor({
         const currentValue = valueRef.current
         const insertAt = textarea.selectionStart ?? currentValue.length
         const needsSpaceBefore = insertAt > 0 && !/\s/.test(currentValue.charAt(insertAt - 1))
-        const insertText = `${needsSpaceBefore ? ' ' : ''}@${context.label} `
+        const insertText = `${needsSpaceBefore ? ' ' : ''}@${prepared.label} `
         const newValue = `${currentValue.slice(0, insertAt)}${insertText}${currentValue.slice(insertAt)}`
-        const newPos = insertAt + insertText.length
 
-        pendingCursorRef.current = newPos
+        pendingCursorRef.current = insertAt + insertText.length
         valueRef.current = newValue
         setValueState(newValue)
       }
 
-      addContextNotified(context)
+      addContextNotified(prepared)
     },
     [textareaRef, addContextNotified]
   )
@@ -923,25 +923,20 @@ export function usePromptEditor({
     const selectionContext = readSelectionContextFromClipboard(e.clipboardData)
     if (selectionContext) {
       e.preventDefault()
-      // A chip's `@label` token must be unique — `addContext` dedupes a matching
-      // label, so inserting a token for an already-present selection would orphan
-      // it (a second token with no backing context). Skip and keep focus, mirroring
-      // insertContextChip.
-      if (
-        isContextAlreadySelected(selectionContext, contextManagementRef.current.selectedContexts)
-      ) {
-        return
-      }
+      const prepared = prepareContextForInsert(
+        selectionContext,
+        contextManagementRef.current.selectedContexts
+      )
+      if (!prepared) return
       const selStart = textarea.selectionStart ?? valueRef.current.length
       const selEnd = textarea.selectionEnd ?? selStart
       const needsSpaceBefore = selStart > 0 && !/\s/.test(valueRef.current.charAt(selStart - 1))
-      const insert = `${needsSpaceBefore ? ' ' : ''}@${selectionContext.label} `
+      const insert = `${needsSpaceBefore ? ' ' : ''}@${prepared.label} `
       textarea.setRangeText(insert, selStart, selEnd, 'end')
-      const newValue = textarea.value
       const caret = selStart + insert.length
-      contextManagementRef.current.addContext(selectionContext)
-      valueRef.current = newValue
-      setValueState(newValue)
+      contextManagementRef.current.addContext(prepared)
+      valueRef.current = textarea.value
+      setValueState(textarea.value)
       requestAnimationFrame(() => textarea.setSelectionRange(caret, caret))
       return
     }
@@ -1038,14 +1033,10 @@ export function usePromptEditor({
    * (the caller must then perform the cut deletion itself, since the default
    * was prevented).
    *
-   * Selection chips (`file_selection` / `table_selection`) can't fit a portable
-   * link — their inline text / row-id payload lives only in the context. When
-   * the selection is exactly one such chip (the common copy/cut of a
-   * highlight-to-chat chip), ride its full context on the custom
-   * `text/x-sim-selection` MIME so paste restores it; otherwise it would leave a
-   * bare `@label` with no backing data. Mixed selections keep the portable/plain
-   * path (the single-slot MIME can't carry more than one), so the chip degrades
-   * to its label text there rather than dropping the rest of the selection.
+   * Selection chips carry an inline text / row-id payload that no portable link
+   * can hold, so a lone selection chip rides the custom `text/x-sim-selection`
+   * MIME instead. That slot fits only one, so a mixed selection keeps the
+   * portable path and its selection chip degrades to bare label text.
    */
   const writeSanitizedClipboard = useCallback(
     (e: React.ClipboardEvent<HTMLTextAreaElement>): boolean => {

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

@@ -19,17 +19,12 @@ import { useQueryState } from 'nuqs'
 import { usePostHog } from 'posthog-js/react'
 import { requestJson } from '@/lib/api/client/request'
 import { createWorkflowContract } from '@/lib/api/contracts'
-import {
-  fileNameFromSelectionLabel,
-  tableNameFromSelectionLabel,
-} from '@/lib/copilot/chat/selection-context'
 import { canonicalWorkspaceFilePath } from '@/lib/copilot/vfs/path-utils'
 import {
   LandingPromptStorage,
   type LandingWorkflowSeed,
   LandingWorkflowSeedStorage,
   MothershipHandoffStorage,
-  MothershipPendingContextStorage,
 } from '@/lib/core/utils/browser-storage'
 import {
   addMothershipContext,
@@ -335,43 +330,37 @@ export function Home({ chatId, userName, userId, tableViewsEnabled }: HomeProps)
   }, [sendMessage])
 
   /**
-   * Consumes a one-shot handoff left by another surface (e.g. "Troubleshoot in
-   * Chat" on an errored log viewed from a different route) and auto-sends it
-   * into this fresh chat, tagging the run so Sim can inspect the failure. Only
-   * the cross-route path lands here — when a chat is already mounted the event
-   * above delivers directly. Gated to the new-chat surface (`!chatId`): a
+   * Consumes a one-shot handoff left by another surface and applies it to this
+   * fresh chat. Two shapes arrive here: a message handoff (e.g. "Troubleshoot in
+   * Chat" on an errored log) is auto-sent with its contexts attached; a
+   * chip-only handoff (highlight-to-chat from the standalone Files/Tables pages)
+   * seeds reference chips and sends nothing.
+   *
+   * Only the cross-route path lands here — when a chat is already mounted the
+   * events deliver directly. Gated to the new-chat surface (`!chatId`): a
    * handoff always targets a fresh chat, so an existing `/chat/[chatId]` mount
    * must never claim it if navigation races. `consume` clears the entry
    * atomically, so it fires at most once even across a StrictMode remount.
+   *
+   * Chip-only handoffs open each resource directly rather than relying on the
+   * input's listener being mounted, then dispatch so the input inserts the chip.
+   * This effect is declared after `useChat`, so its chat-init `setResources([])`
+   * has already flushed and cannot wipe the just-opened resource.
    */
   useEffect(() => {
     if (chatId) return
     const handoff = MothershipHandoffStorage.consume(workspaceId)
-    if (handoff) sendMessage(handoff.message, undefined, handoff.contexts)
-  }, [chatId, workspaceId, sendMessage])
-
-  /**
-   * Drains contexts persisted by the highlight-to-chat action (standalone
-   * Files/Tables page). Runs after this component's mount effects — including
-   * `useChat`'s chat-init `setResources([])` — so re-dispatching each context
-   * inserts its chip in the (already mounted) conversation input AND opens its
-   * resource in the slideover without the reset wiping it. A ref guards against
-   * the StrictMode double-invoke draining twice.
-   */
-  const hasDrainedPendingContextRef = useRef(false)
-  useEffect(() => {
-    if (hasDrainedPendingContextRef.current || !workspaceId) return
-    hasDrainedPendingContextRef.current = true
-    const pending = MothershipPendingContextStorage.consume(workspaceId)
-    for (const context of pending) {
-      // Open the resource in the slideover directly (deterministic — not
-      // dependent on the input's event listener being mounted yet), then
-      // dispatch the event so the mounted input inserts the chip.
+    if (!handoff) return
+    if (handoff.message) {
+      sendMessage(handoff.message, undefined, handoff.contexts)
+      return
+    }
+    for (const context of handoff.contexts ?? []) {
       handleContextAdd(context)
       addMothershipContext(context)
     }
-    // eslint-disable-next-line react-hooks/exhaustive-deps -- mount-only drain; handleContextAdd is stable enough for a one-shot
-  }, [workspaceId])
+    // eslint-disable-next-line react-hooks/exhaustive-deps -- one-shot drain; handleContextAdd is a stable body function
+  }, [chatId, workspaceId, sendMessage])
 
   function resolveResourceFromContext(
     context: ChatContext
@@ -396,13 +385,13 @@ export function Home({ chatId, userName, userId, tableViewsEnabled }: HomeProps)
   }
 
   /**
-   * Tab title for the resource a chip opens. Selection chips carry a
-   * location suffix in their label (`notes.md:12-40`, `Sales (3 rows)`); the
-   * underlying resource is the whole file/table, so strip the suffix.
+   * Tab title for the resource a chip opens. A selection chip's label describes
+   * the selection (`notes.md:12-40`, `Sales (3 rows)`) but the tab shows the
+   * whole file/table, so title it from the resource name the context carries.
    */
   function resourceTitleForContext(context: ChatContext): string {
-    if (context.kind === 'file_selection') return fileNameFromSelectionLabel(context.label)
-    if (context.kind === 'table_selection') return tableNameFromSelectionLabel(context.label)
+    if (context.kind === 'file_selection') return context.fileName
+    if (context.kind === 'table_selection') return context.tableName
     return context.label
   }
 

apps/sim/app/workspace/[workspaceId]/home/hooks/use-chat.ts

@@ -318,13 +318,18 @@ function isChatContext(value: unknown): value is ChatContext {
     case 'table_selection':
       return (
         typeof value.tableId === 'string' &&
+        typeof value.tableName === 'string' &&
         Array.isArray(value.rowIds) &&
         value.rowIds.every((id) => typeof id === 'string')
       )
     case 'file':
       return typeof value.fileId === 'string'
     case 'file_selection':
-      return typeof value.fileId === 'string' && typeof value.text === 'string'
+      return (
+        typeof value.fileId === 'string' &&
+        typeof value.fileName === 'string' &&
+        typeof value.text === 'string'
+      )
     case 'folder':
       return typeof value.folderId === 'string'
     case 'filefolder':
@@ -3231,13 +3236,15 @@ export function useChat(
         ...(c.kind === 'mcp' && 'serverId' in c ? { serverId: c.serverId } : {}),
         ...(c.kind === 'file_selection'
           ? {
+              fileName: c.fileName,
               text: c.text,
               ...(c.startLine ? { startLine: c.startLine } : {}),
               ...(c.endLine ? { endLine: c.endLine } : {}),
             }
           : {}),
         ...(c.kind === 'table_selection'
           ? {
+              tableName: c.tableName,
               rowIds: c.rowIds,
               ...(c.columnIds ? { columnIds: c.columnIds } : {}),
             }

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

@@ -150,9 +150,13 @@ export interface ChatMessageContext {
   serverId?: string
   /** Selected passage for a `file_selection` context. */
   text?: string
+  /** Source file name for a `file_selection` context. */
+  fileName?: string
   /** 1-based inclusive line range for a `file_selection` context. */
   startLine?: number
   endLine?: number
+  /** Source table name for a `table_selection` context. */
+  tableName?: string
   /** Selected row ids for a `table_selection` context. */
   rowIds?: string[]
   /** Selected column ids for a `table_selection` cell range. */