fix(desktop): pasting into an open @url: scope no longer doubles the directive

A pasted link linkifies into an `@url:` directive, so pasting one while an
@url: scope was already open stacked a second directive on the first and
submitted `@url:@url:` around the link. The leftover prefix rendered as
literal text in front of the chip.

insertComposerContentsAtCaret takes a consumeBefore length; both composers
pass the open scope's span so the scope is consumed by the paste rather than
left sitting in front of the chip.

apps/desktop/src/app/chat/composer/index.tsx

@@ -67,7 +67,7 @@ import {
 import { useComposerScope } from './scope'
 import { ComposerStatusStack } from './status-stack'
 import { CodingStatusRow } from './status-stack/coding-row'
-import { extractClipboardImageBlobs } from './text-utils'
+import { extractClipboardImageBlobs, openDirectiveScope } from './text-utils'
 import { ComposerTriggerPopover } from './trigger-popover'
 import type { ChatBarProps } from './types'
 import { isRedoShortcut, isUndoShortcut } from './undo-history'
@@ -491,8 +491,13 @@ export function ChatBar({
     // Links in the paste land as `@url:` chips rather than a wall of URL text —
     // the same reference the "Add URL" dialog inserts, parsed in place so a link
     // mid-sentence keeps its position. Bare `@path` tokens promote the same way.
+    // A paste into an open `@url:`/`@file:` scope CONSUMES that scope instead of
+    // stacking on it — the scope is the browse mode the user is pasting into,
+    // not text they typed and want to keep (`@url:@url:\`https://…\``).
+    const scope = openDirectiveScope(event.currentTarget)
+
     recordUndoPoint()
-    insertComposerContentsAtCaret(event.currentTarget, pathifyRefs(linkifyUrls(pastedText)))
+    insertComposerContentsAtCaret(event.currentTarget, pathifyRefs(linkifyUrls(pastedText)), scope)
     scheduleFlushEditorToDraft(event.currentTarget)
   }
 
@@ -1138,6 +1143,7 @@ export function ChatBar({
                 loading={triggerLoading}
                 onHover={setTriggerActive}
                 onPick={replaceTriggerWithChip}
+                scope={trigger.scope}
               />
             )}
             {!poppedOut && (

apps/desktop/src/app/chat/composer/rich-editor.ts

@@ -228,8 +228,24 @@ function atTokenBoundary(editor: HTMLElement, range: Range | null): boolean {
  *  — Chromium's editing pipeline is ~O(n²) on large multiline blobs.
  *
  *  The text arrives whole rather than typed, so a `/command` ending it is
- *  complete rather than half-written and chips like the rest. */
-export function insertComposerContentsAtCaret(editor: HTMLElement, text: string) {
+ *  complete rather than half-written and chips like the rest.
+ *
+ *  `consumeBefore` characters immediately before the caret are swallowed by the
+ *  insert. That's how a paste into an open `@url:` scope replaces the scope
+ *  instead of stacking on it (`@url:@url:\`https://…\``). */
+export function insertComposerContentsAtCaret(editor: HTMLElement, text: string, consumeBefore = 0) {
+  const scoped = consumeBefore > 0 ? rangeBeforeCaret(editor, consumeBefore) : null
+
+  if (scoped) {
+    scoped.deleteContents()
+    scoped.collapse(true)
+
+    const selection = window.getSelection()
+
+    selection?.removeAllRanges()
+    selection?.addRange(scoped)
+  }
+
   const hit = composerSelectionRange(editor)
   const fragment = document.createDocumentFragment()
 

apps/desktop/src/app/chat/composer/text-utils.ts

@@ -164,18 +164,13 @@ export function textBeforeCaret(editor: HTMLDivElement): string | null {
   return serializeTextBefore(editor, range.startContainer, range.startOffset)
 }
 
-/** A directive scope the caret is sitting inside (`@url:` with nothing typed
- *  after it), and how many characters it occupies. A paste or a picked value
- *  lands INTO that scope: the scope text is consumed rather than left in front
- *  of the chip as leftover syntax. */
-export function openDirectiveScope(editor: HTMLDivElement): { length: number; scope: DirectiveScope } | null {
+/** How many characters of directive scope the caret is sitting inside (`@url:`
+ *  with nothing typed after it), or 0. A paste lands INTO that scope: the scope
+ *  text is consumed rather than left in front of the chip as leftover syntax. */
+export function openDirectiveScope(editor: HTMLDivElement): number {
   const trigger = detectTrigger(textBeforeCaret(editor) ?? '')
 
-  if (trigger?.kind !== '@' || !trigger.scope || trigger.value) {
-    return null
-  }
-
-  return { length: trigger.tokenLength, scope: trigger.scope }
+  return trigger?.kind === '@' && trigger.scope && !trigger.value ? trigger.tokenLength : 0
 }
 
 export function detectTrigger(textBefore: string): TriggerState | null {

apps/desktop/src/components/assistant-ui/thread/user-edit-composer.tsx

@@ -23,6 +23,7 @@ import {
   releaseActiveComposer
 } from '@/app/chat/composer/focus'
 import { useAtCompletions } from '@/app/chat/composer/hooks/use-at-completions'
+import { rebuildAroundCaret } from '@/app/chat/composer/hooks/use-composer-trigger'
 import { useComposerUndo } from '@/app/chat/composer/hooks/use-composer-undo'
 import { useEmojiCompletions } from '@/app/chat/composer/hooks/use-emoji-completions'
 import { useSlashCompletions } from '@/app/chat/composer/hooks/use-slash-completions'
@@ -42,7 +43,7 @@ import {
   replaceBeforeCaret,
   RICH_INPUT_SLOT
 } from '@/app/chat/composer/rich-editor'
-import { detectTrigger, textBeforeCaret, type TriggerState } from '@/app/chat/composer/text-utils'
+import { detectTrigger, openDirectiveScope, textBeforeCaret, type TriggerState } from '@/app/chat/composer/text-utils'
 import { ComposerTriggerPopover } from '@/app/chat/composer/trigger-popover'
 import { isRedoShortcut, isUndoShortcut } from '@/app/chat/composer/undo-history'
 import { chipTypedUrlOnSpace, linkifyUrls } from '@/app/chat/composer/url-refs'
@@ -352,9 +353,7 @@ export const UserEditComposer: FC<UserEditComposerProps> = ({ cwd, gateway, sess
         : fragment.append(document.createTextNode(text))
 
       if (!replaceBeforeCaret(editor, trigger.tokenLength, fragment)) {
-        const current = composerPlainText(editor)
-        renderComposerContents(editor, `${current.slice(0, Math.max(0, current.length - trigger.tokenLength))}${text}`)
-        placeCaretEnd(editor)
+        rebuildAroundCaret(editor, trigger.tokenLength, text)
       }
 
       finish()
@@ -555,8 +554,14 @@ export const UserEditComposer: FC<UserEditComposerProps> = ({ cwd, gateway, sess
     rememberInitialDraft()
     recordUndoPoint()
 
-    // Links land as `@url:` chips, same as the main composer.
-    insertComposerContentsAtCaret(event.currentTarget, pathifyRefs(linkifyUrls(pastedText)))
+    // Links land as `@url:` chips, same as the main composer — including
+    // consuming an open `@url:` scope rather than stacking a second directive
+    // in front of the chip.
+    insertComposerContentsAtCaret(
+      event.currentTarget,
+      pathifyRefs(linkifyUrls(pastedText)),
+      openDirectiveScope(event.currentTarget)
+    )
     syncDraftFromEditor(event.currentTarget)
   }