diff --git a/src/chrome/src/ui/selection-quote.js b/src/chrome/src/ui/selection-quote.js
new file mode 100644
index 000000000..026329071
--- /dev/null
+++ b/src/chrome/src/ui/selection-quote.js
@@ -0,0 +1,68 @@
+const ELEMENT_NODE = 1;
+const TEXT_NODE = 3;
+const QUOTE_CHROME_TAGS = new Set(['BUTTON', 'INPUT', 'TEXTAREA', 'SELECT', 'SCRIPT', 'STYLE', 'TEMPLATE']);
+const QUOTE_CHROME_CLASSES = new Set(['code-block-header', 'code-copy-btn', 'code-lang', 'msg-copy-btn']);
+
+function normalizedSelectionText(text) {
+  return String(text == null ? '' : text).replace(/\r\n?/g, '\n').trim();
+}
+
+function classListContains(node, className) {
+  if (node?.classList?.contains?.(className)) return true;
+  const classNameValue = typeof node?.className === 'string' ? node.className : '';
+  return classNameValue.split(/\s+/).includes(className);
+}
+
+export function isSelectionQuoteChrome(node) {
+  if (!node || node.nodeType !== ELEMENT_NODE) return false;
+  if (QUOTE_CHROME_TAGS.has(String(node.tagName || '').toUpperCase())) return true;
+  for (const className of QUOTE_CHROME_CLASSES) {
+    if (classListContains(node, className)) return true;
+  }
+  return false;
+}
+
+function collectSelectionQuoteText(node) {
+  if (!node) return '';
+  if (node.nodeType === TEXT_NODE) return String(node.nodeValue ?? node.textContent ?? '');
+  if (node.nodeType !== ELEMENT_NODE) return '';
+  if (isSelectionQuoteChrome(node)) return '';
+  if (String(node.tagName || '').toUpperCase() === 'BR') return '\n';
+  let text = '';
+  for (const child of node.childNodes || []) text += collectSelectionQuoteText(child);
+  return text;
+}
+
+export function selectionTextFromContents(root) {
+  return normalizedSelectionText(collectSelectionQuoteText(root));
+}
+
+export function selectionTextFromRange(range) {
+  if (!range) return '';
+  if (typeof range.cloneContents === 'function') {
+    return selectionTextFromContents(range.cloneContents());
+  }
+  return normalizedSelectionText(range.toString?.() || '');
+}
+
+export function buildSelectionQuote(text) {
+  const selection = normalizedSelectionText(text);
+  if (!selection) return '';
+  return `${selection.split('\n').map((line) => `> ${line}`).join('\n')}\n\n`;
+}
+
+export function buildSelectionComposerDraft(selectionText, draft = '') {
+  const quote = buildSelectionQuote(selectionText);
+  const existingDraft = String(draft == null ? '' : draft);
+  if (!quote || existingDraft.startsWith(quote)) return existingDraft;
+  return `${quote}${existingDraft}`;
+}
+
+export function selectionIsQuoteable({ startTextElement, endTextElement, text } = {}) {
+  // A range spanning two bubbles has no unambiguous answer boundary.
+  return Boolean(
+    startTextElement
+      && startTextElement === endTextElement
+      && normalizedSelectionText(text),
+  );
+}
diff --git a/src/chrome/src/ui/sidepanel.html b/src/chrome/src/ui/sidepanel.html
index 2025e6eb5..194b7c06f 100644
--- a/src/chrome/src/ui/sidepanel.html
+++ b/src/chrome/src/ui/sidepanel.html
@@ -356,6 +356,8 @@ <h2 id="new-conversation-confirm-title" data-i18n="sp.clear.title">Start a new c
       <button id="selection-scope-new-conversation" type="button" data-i18n="sp.btn.clear">New conversation</button>
     </div>
 
+    <button id="selection-ask-action" class="selection-ask-action hidden" type="button"></button>
+
     <!-- Input Area -->
     <div id="input-area">
       <div id="mode-toggle">
diff --git a/src/chrome/src/ui/sidepanel.js b/src/chrome/src/ui/sidepanel.js
index f9e6ee0a3..edb77c9a0 100644
--- a/src/chrome/src/ui/sidepanel.js
+++ b/src/chrome/src/ui/sidepanel.js
@@ -29,6 +29,8 @@ import { runUiUnavailableBeforeSeq } from '../run-ui-journal.js';
 import { formatErrorMessage } from '../error-format.js';
 import { buildMessageInfoPills } from '../message-info.js';
 import { escapeHtml } from './utils.js';
+import { buildSelectionComposerDraft, selectionIsQuoteable, selectionTextFromRange } from './selection-quote.js';
+import { getSelectionShortcutLocalization } from '../selection-shortcut-i18n.js';
 import {
   isBackgroundConnectionError,
   runDetachedWithReconnect,
@@ -535,6 +537,7 @@ const selectionScopeBannerEl = document.getElementById('selection-scope-banner')
 const selectionScopeTitleEl = document.getElementById('selection-scope-title');
 const selectionScopeDescriptionEl = document.getElementById('selection-scope-description');
 const selectionScopeNewConversationBtn = document.getElementById('selection-scope-new-conversation');
+const selectionAskActionEl = document.getElementById('selection-ask-action');
 const historyBtn = document.getElementById('btn-history');
 const expandBtn = document.getElementById('btn-expand');
 const settingsBtn = document.getElementById('btn-settings');
@@ -589,6 +592,11 @@ const ASK_PLACEHOLDER_KEYS = [
   'sp.input.placeholder_tip.record',
 ];
 const PERMISSION_REMINDER_PLACEHOLDER_KEY = 'sp.input.placeholder_tip.skip_permissions';
+let pendingAnswerSelection = null;
+let selectionAskActionRefreshFrame = null;
+let selectionAskPointerDown = false;
+let selectionAskActionLocale = '';
+let selectionAskActionLabel = '';
 const SLASH_COMMANDS = [
   { value: '/help', usage: '/help', descriptionKey: 'sp.slash.help', action: 'show', outOfBand: true },
   {
@@ -2252,6 +2260,7 @@ function drainQueuedComposerMessageForCurrentTab() {
 }
 
 async function renderClearedConversationForTab(tabId) {
+  dismissSelectionAskAction();
   setSelectionGroundedForTab(tabId, false);
   const clearResult = await clearCachedTabChat(tabId);
   if (!clearResult?.ok || clearResult?.skipped) {
@@ -4208,6 +4217,7 @@ if (verboseBtn) {
 
 async function switchToTab(newTabId) {
   if (newTabId === currentTabId && renderedTabId === newTabId) { return; }
+  dismissSelectionAskAction();
   if (newConversationConfirmationState
       && !sameTabId(newConversationConfirmationState.tabId, newTabId)) {
     settleNewConversationConfirmation(false, { restoreFocus: false });
@@ -7854,6 +7864,7 @@ async function sendMessage(extraChatParams = {}) {
       ...(retryOptions ? { __retry: { ...retryOptions, mode: 'ask' } } : {}),
     };
   }
+  dismissSelectionAskAction();
   const retryOptions = extraChatParams?.__retry || null;
   const modeOverride = ['ask', 'act', 'dev'].includes(extraChatParams?.__mode) ? extraChatParams.__mode : null;
   const onContextMenuClaimRejected = typeof extraChatParams?.__onContextMenuClaimRejected === 'function'
@@ -10678,6 +10689,126 @@ function refreshOpenMessageInfoRows() {
   });
 }
 
+function assistantTextElementForSelectionNode(node) {
+  const element = node?.nodeType === 1 ? node : node?.parentElement;
+  return element?.closest?.('.message.assistant .message-text') || null;
+}
+
+function selectedAssistantAnswer() {
+  const selection = window.getSelection?.();
+  if (!selection || selection.rangeCount !== 1 || selection.isCollapsed) return null;
+  const range = selection.getRangeAt(0);
+  if (!range.startContainer.isConnected || !range.endContainer.isConnected) return null;
+  const startTextElement = assistantTextElementForSelectionNode(range.startContainer);
+  const endTextElement = assistantTextElementForSelectionNode(range.endContainer);
+  const text = selectionTextFromRange(range);
+  if (!selectionIsQuoteable({ startTextElement, endTextElement, text })) return null;
+  return { range, text };
+}
+
+function dismissSelectionAskAction() {
+  if (selectionAskActionRefreshFrame != null) {
+    cancelAnimationFrame(selectionAskActionRefreshFrame);
+    selectionAskActionRefreshFrame = null;
+  }
+  pendingAnswerSelection = null;
+  selectionAskActionEl?.classList.add('hidden');
+}
+
+function positionSelectionAskAction(range) {
+  if (!selectionAskActionEl || !range) return;
+  const rect = range.getBoundingClientRect();
+  if (!rect.width && !rect.height) {
+    dismissSelectionAskAction();
+    return;
+  }
+  const gap = 6;
+  const actionRect = selectionAskActionEl.getBoundingClientRect();
+  const left = Math.min(
+    Math.max(8, rect.left),
+    Math.max(8, window.innerWidth - actionRect.width - 8),
+  );
+  const belowTop = rect.bottom + gap;
+  const preferredTop = belowTop + actionRect.height <= window.innerHeight - 8
+    ? belowTop
+    : Math.max(8, rect.top - actionRect.height - gap);
+  const top = Math.min(
+    Math.max(8, window.innerHeight - actionRect.height - 8),
+    preferredTop,
+  );
+  selectionAskActionEl.style.left = `${left}px`;
+  selectionAskActionEl.style.top = `${top}px`;
+}
+
+function applySelectionAskActionLabel() {
+  if (!selectionAskActionEl) return;
+  const locale = getLocale();
+  if (selectionAskActionLocale === locale && selectionAskActionLabel
+      && selectionAskActionEl.textContent === selectionAskActionLabel) {
+    return;
+  }
+  selectionAskActionLocale = locale;
+  selectionAskActionLabel = getSelectionShortcutLocalization(locale).strings.askQuestion;
+  selectionAskActionEl.textContent = selectionAskActionLabel;
+  selectionAskActionEl.title = selectionAskActionLabel;
+  selectionAskActionEl.setAttribute('aria-label', selectionAskActionLabel);
+}
+
+function refreshSelectionAskAction() {
+  const selected = selectedAssistantAnswer();
+  if (!selected || !selectionAskActionEl) {
+    dismissSelectionAskAction();
+    return;
+  }
+  pendingAnswerSelection = selected;
+  applySelectionAskActionLabel();
+  selectionAskActionEl.classList.remove('hidden');
+  positionSelectionAskAction(selected.range);
+}
+
+function scheduleSelectionAskActionRefresh({ force = false } = {}) {
+  if (!force && selectionAskPointerDown) return;
+  if (selectionAskActionRefreshFrame != null) return;
+  selectionAskActionRefreshFrame = requestAnimationFrame(() => {
+    selectionAskActionRefreshFrame = null;
+    if (!force && selectionAskPointerDown) return;
+    refreshSelectionAskAction();
+  });
+}
+
+function handleSelectionAskPointerDown(event) {
+  if (selectionAskActionEl?.contains(event.target)) return;
+  selectionAskPointerDown = true;
+  dismissSelectionAskAction();
+}
+
+function handleSelectionAskPointerUp() {
+  if (!selectionAskPointerDown) return;
+  selectionAskPointerDown = false;
+  scheduleSelectionAskActionRefresh({ force: true });
+}
+
+function askAboutSelectedAnswer() {
+  const selection = pendingAnswerSelection;
+  if (!selection) return;
+  const liveSelection = selectedAssistantAnswer();
+  if (!liveSelection) {
+    dismissSelectionAskAction();
+    return;
+  }
+  const nextDraft = buildSelectionComposerDraft(liveSelection.text, inputEl.value);
+  if (nextDraft === inputEl.value) {
+    dismissSelectionAskAction();
+    return;
+  }
+  inputEl.value = nextDraft;
+  dismissSelectionAskAction();
+  window.getSelection?.()?.removeAllRanges();
+  handleInput();
+  inputEl.focus();
+  inputEl.setSelectionRange(inputEl.value.length, inputEl.value.length);
+}
+
 function addMessage(role, content, options = {}) {
   const msgEl = document.createElement('div');
   msgEl.className = `message ${role}`;
@@ -11677,6 +11808,11 @@ async function handleGlobalKeydown(e) {
   if (e.key === 'Escape') {
     const slashMenuOpen = !!slashCommandMenuEl && !slashCommandMenuEl.classList.contains('hidden');
     if (slashMenuOpen) return;
+    if (selectionAskActionEl && !selectionAskActionEl.classList.contains('hidden')) {
+      e.preventDefault();
+      dismissSelectionAskAction();
+      return;
+    }
     if (isProcessing) {
       e.preventDefault();
       abortRun();
@@ -12683,6 +12819,26 @@ if (attachBtn && fileAttachInput) {
 
 // --- Event Listeners ---
 
+if (selectionAskActionEl) {
+  selectionAskActionEl.addEventListener('mousedown', (event) => event.preventDefault());
+  selectionAskActionEl.addEventListener('click', (event) => {
+    event.stopPropagation();
+    askAboutSelectedAnswer();
+  });
+  document.addEventListener('selectionchange', scheduleSelectionAskActionRefresh);
+  document.addEventListener('pointerdown', handleSelectionAskPointerDown);
+  document.addEventListener('pointerup', handleSelectionAskPointerUp);
+  document.addEventListener('pointercancel', handleSelectionAskPointerUp);
+  document.addEventListener('keyup', scheduleSelectionAskActionRefresh);
+  chatContainerEl?.addEventListener('scroll', dismissSelectionAskAction, { passive: true });
+  window.addEventListener('resize', dismissSelectionAskAction);
+  document.addEventListener('wb-locale-changed', () => {
+    selectionAskActionLocale = '';
+    applySelectionAskActionLabel();
+    scheduleSelectionAskActionRefresh();
+  });
+}
+
 sendBtn.addEventListener('click', sendMessage);
 
 document.addEventListener('keydown', handleGlobalKeydown, true);
diff --git a/src/chrome/styles/sidepanel.css b/src/chrome/styles/sidepanel.css
index 8079b983b..1074cdf7b 100644
--- a/src/chrome/styles/sidepanel.css
+++ b/src/chrome/styles/sidepanel.css
@@ -2310,6 +2310,8 @@ body {
   font-size: 10px;
   font-weight: 700;
   line-height: 1.2;
+  overflow: hidden;
+  text-overflow: ellipsis;
   white-space: nowrap;
 }
 
@@ -2337,6 +2339,39 @@ body {
   opacity: 0.48;
 }
 
+.selection-ask-action {
+  position: fixed;
+  z-index: 30;
+  max-width: calc(100vw - 16px);
+  padding: 6px 10px;
+  border: 1px solid color-mix(in srgb, var(--accent) 45%, var(--border));
+  border-radius: 999px;
+  background: var(--bg-secondary);
+  box-shadow: 0 5px 16px color-mix(in srgb, var(--text-primary) 18%, transparent);
+  color: var(--text-primary);
+  cursor: pointer;
+  font: inherit;
+  font-size: 11px;
+  font-weight: 700;
+  line-height: 1.2;
+  user-select: none;
+  white-space: nowrap;
+}
+
+.selection-ask-action.hidden {
+  display: none;
+}
+
+.selection-ask-action:hover {
+  border-color: var(--accent);
+  background: var(--accent-dim);
+}
+
+.selection-ask-action:focus-visible {
+  outline: 3px solid color-mix(in srgb, var(--accent) 34%, transparent);
+  outline-offset: 2px;
+}
+
 
 
 /* Context-aware recommendations — inline centered pill row in the chat body */
diff --git a/src/firefox/src/ui/selection-quote.js b/src/firefox/src/ui/selection-quote.js
new file mode 100644
index 000000000..026329071
--- /dev/null
+++ b/src/firefox/src/ui/selection-quote.js
@@ -0,0 +1,68 @@
+const ELEMENT_NODE = 1;
+const TEXT_NODE = 3;
+const QUOTE_CHROME_TAGS = new Set(['BUTTON', 'INPUT', 'TEXTAREA', 'SELECT', 'SCRIPT', 'STYLE', 'TEMPLATE']);
+const QUOTE_CHROME_CLASSES = new Set(['code-block-header', 'code-copy-btn', 'code-lang', 'msg-copy-btn']);
+
+function normalizedSelectionText(text) {
+  return String(text == null ? '' : text).replace(/\r\n?/g, '\n').trim();
+}
+
+function classListContains(node, className) {
+  if (node?.classList?.contains?.(className)) return true;
+  const classNameValue = typeof node?.className === 'string' ? node.className : '';
+  return classNameValue.split(/\s+/).includes(className);
+}
+
+export function isSelectionQuoteChrome(node) {
+  if (!node || node.nodeType !== ELEMENT_NODE) return false;
+  if (QUOTE_CHROME_TAGS.has(String(node.tagName || '').toUpperCase())) return true;
+  for (const className of QUOTE_CHROME_CLASSES) {
+    if (classListContains(node, className)) return true;
+  }
+  return false;
+}
+
+function collectSelectionQuoteText(node) {
+  if (!node) return '';
+  if (node.nodeType === TEXT_NODE) return String(node.nodeValue ?? node.textContent ?? '');
+  if (node.nodeType !== ELEMENT_NODE) return '';
+  if (isSelectionQuoteChrome(node)) return '';
+  if (String(node.tagName || '').toUpperCase() === 'BR') return '\n';
+  let text = '';
+  for (const child of node.childNodes || []) text += collectSelectionQuoteText(child);
+  return text;
+}
+
+export function selectionTextFromContents(root) {
+  return normalizedSelectionText(collectSelectionQuoteText(root));
+}
+
+export function selectionTextFromRange(range) {
+  if (!range) return '';
+  if (typeof range.cloneContents === 'function') {
+    return selectionTextFromContents(range.cloneContents());
+  }
+  return normalizedSelectionText(range.toString?.() || '');
+}
+
+export function buildSelectionQuote(text) {
+  const selection = normalizedSelectionText(text);
+  if (!selection) return '';
+  return `${selection.split('\n').map((line) => `> ${line}`).join('\n')}\n\n`;
+}
+
+export function buildSelectionComposerDraft(selectionText, draft = '') {
+  const quote = buildSelectionQuote(selectionText);
+  const existingDraft = String(draft == null ? '' : draft);
+  if (!quote || existingDraft.startsWith(quote)) return existingDraft;
+  return `${quote}${existingDraft}`;
+}
+
+export function selectionIsQuoteable({ startTextElement, endTextElement, text } = {}) {
+  // A range spanning two bubbles has no unambiguous answer boundary.
+  return Boolean(
+    startTextElement
+      && startTextElement === endTextElement
+      && normalizedSelectionText(text),
+  );
+}
diff --git a/src/firefox/src/ui/sidepanel.html b/src/firefox/src/ui/sidepanel.html
index 8fa8fba48..d1bd79aba 100644
--- a/src/firefox/src/ui/sidepanel.html
+++ b/src/firefox/src/ui/sidepanel.html
@@ -311,6 +311,8 @@ <h2 id="new-conversation-confirm-title" data-i18n="sp.clear.title">Start a new c
       <button id="selection-scope-new-conversation" type="button" data-i18n="sp.btn.clear">New conversation</button>
     </div>
 
+    <button id="selection-ask-action" class="selection-ask-action hidden" type="button"></button>
+
     <!-- Input Area -->
     <div id="input-area">
       <div id="mode-toggle">
diff --git a/src/firefox/src/ui/sidepanel.js b/src/firefox/src/ui/sidepanel.js
index 854dbe6ec..a1041785d 100644
--- a/src/firefox/src/ui/sidepanel.js
+++ b/src/firefox/src/ui/sidepanel.js
@@ -29,6 +29,8 @@ import { runUiUnavailableBeforeSeq } from '../run-ui-journal.js';
 import { formatErrorMessage } from '../error-format.js';
 import { buildMessageInfoPills } from '../message-info.js';
 import { escapeHtml } from './utils.js';
+import { buildSelectionComposerDraft, selectionIsQuoteable, selectionTextFromRange } from './selection-quote.js';
+import { getSelectionShortcutLocalization } from '../selection-shortcut-i18n.js';
 import {
   isBackgroundConnectionError,
   runDetachedWithReconnect,
@@ -414,6 +416,7 @@ const selectionScopeBannerEl = document.getElementById('selection-scope-banner')
 const selectionScopeTitleEl = document.getElementById('selection-scope-title');
 const selectionScopeDescriptionEl = document.getElementById('selection-scope-description');
 const selectionScopeNewConversationBtn = document.getElementById('selection-scope-new-conversation');
+const selectionAskActionEl = document.getElementById('selection-ask-action');
 const historyBtn = document.getElementById('btn-history');
 const expandBtn = document.getElementById('btn-expand');
 const settingsBtn = document.getElementById('btn-settings');
@@ -465,6 +468,11 @@ const ASK_PLACEHOLDER_KEYS = [
   'sp.input.placeholder_tip.help',
 ];
 const PERMISSION_REMINDER_PLACEHOLDER_KEY = 'sp.input.placeholder_tip.skip_permissions';
+let pendingAnswerSelection = null;
+let selectionAskActionRefreshFrame = null;
+let selectionAskPointerDown = false;
+let selectionAskActionLocale = '';
+let selectionAskActionLabel = '';
 const SLASH_COMMANDS = [
   { value: '/help', usage: '/help', descriptionKey: 'sp.slash.help', action: 'show', outOfBand: true },
   {
@@ -2415,6 +2423,7 @@ function drainQueuedComposerMessageForCurrentTab() {
 }
 
 async function renderClearedConversationForTab(tabId) {
+  dismissSelectionAskAction();
   setSelectionGroundedForTab(tabId, false);
   const clearResult = await clearCachedTabChat(tabId);
   if (!clearResult?.ok || clearResult?.skipped) {
@@ -4054,6 +4063,7 @@ if (verboseBtn) {
 
 async function switchToTab(newTabId) {
   if (newTabId === currentTabId && renderedTabId === newTabId) { return; }
+  dismissSelectionAskAction();
   if (newConversationConfirmationState
       && !sameTabId(newConversationConfirmationState.tabId, newTabId)) {
     settleNewConversationConfirmation(false, { restoreFocus: false });
@@ -7529,6 +7539,7 @@ async function sendMessage(extraChatParams = {}) {
       ...(retryOptions ? { __retry: { ...retryOptions, mode: 'ask' } } : {}),
     };
   }
+  dismissSelectionAskAction();
   const retryOptions = extraChatParams?.__retry || null;
   const modeOverride = ['ask', 'act', 'dev'].includes(extraChatParams?.__mode) ? extraChatParams.__mode : null;
   const onContextMenuClaimRejected = typeof extraChatParams?.__onContextMenuClaimRejected === 'function'
@@ -10299,6 +10310,126 @@ function refreshOpenMessageInfoRows() {
   });
 }
 
+function assistantTextElementForSelectionNode(node) {
+  const element = node?.nodeType === 1 ? node : node?.parentElement;
+  return element?.closest?.('.message.assistant .message-text') || null;
+}
+
+function selectedAssistantAnswer() {
+  const selection = window.getSelection?.();
+  if (!selection || selection.rangeCount !== 1 || selection.isCollapsed) return null;
+  const range = selection.getRangeAt(0);
+  if (!range.startContainer.isConnected || !range.endContainer.isConnected) return null;
+  const startTextElement = assistantTextElementForSelectionNode(range.startContainer);
+  const endTextElement = assistantTextElementForSelectionNode(range.endContainer);
+  const text = selectionTextFromRange(range);
+  if (!selectionIsQuoteable({ startTextElement, endTextElement, text })) return null;
+  return { range, text };
+}
+
+function dismissSelectionAskAction() {
+  if (selectionAskActionRefreshFrame != null) {
+    cancelAnimationFrame(selectionAskActionRefreshFrame);
+    selectionAskActionRefreshFrame = null;
+  }
+  pendingAnswerSelection = null;
+  selectionAskActionEl?.classList.add('hidden');
+}
+
+function positionSelectionAskAction(range) {
+  if (!selectionAskActionEl || !range) return;
+  const rect = range.getBoundingClientRect();
+  if (!rect.width && !rect.height) {
+    dismissSelectionAskAction();
+    return;
+  }
+  const gap = 6;
+  const actionRect = selectionAskActionEl.getBoundingClientRect();
+  const left = Math.min(
+    Math.max(8, rect.left),
+    Math.max(8, window.innerWidth - actionRect.width - 8),
+  );
+  const belowTop = rect.bottom + gap;
+  const preferredTop = belowTop + actionRect.height <= window.innerHeight - 8
+    ? belowTop
+    : Math.max(8, rect.top - actionRect.height - gap);
+  const top = Math.min(
+    Math.max(8, window.innerHeight - actionRect.height - 8),
+    preferredTop,
+  );
+  selectionAskActionEl.style.left = `${left}px`;
+  selectionAskActionEl.style.top = `${top}px`;
+}
+
+function applySelectionAskActionLabel() {
+  if (!selectionAskActionEl) return;
+  const locale = getLocale();
+  if (selectionAskActionLocale === locale && selectionAskActionLabel
+      && selectionAskActionEl.textContent === selectionAskActionLabel) {
+    return;
+  }
+  selectionAskActionLocale = locale;
+  selectionAskActionLabel = getSelectionShortcutLocalization(locale).strings.askQuestion;
+  selectionAskActionEl.textContent = selectionAskActionLabel;
+  selectionAskActionEl.title = selectionAskActionLabel;
+  selectionAskActionEl.setAttribute('aria-label', selectionAskActionLabel);
+}
+
+function refreshSelectionAskAction() {
+  const selected = selectedAssistantAnswer();
+  if (!selected || !selectionAskActionEl) {
+    dismissSelectionAskAction();
+    return;
+  }
+  pendingAnswerSelection = selected;
+  applySelectionAskActionLabel();
+  selectionAskActionEl.classList.remove('hidden');
+  positionSelectionAskAction(selected.range);
+}
+
+function scheduleSelectionAskActionRefresh({ force = false } = {}) {
+  if (!force && selectionAskPointerDown) return;
+  if (selectionAskActionRefreshFrame != null) return;
+  selectionAskActionRefreshFrame = requestAnimationFrame(() => {
+    selectionAskActionRefreshFrame = null;
+    if (!force && selectionAskPointerDown) return;
+    refreshSelectionAskAction();
+  });
+}
+
+function handleSelectionAskPointerDown(event) {
+  if (selectionAskActionEl?.contains(event.target)) return;
+  selectionAskPointerDown = true;
+  dismissSelectionAskAction();
+}
+
+function handleSelectionAskPointerUp() {
+  if (!selectionAskPointerDown) return;
+  selectionAskPointerDown = false;
+  scheduleSelectionAskActionRefresh({ force: true });
+}
+
+function askAboutSelectedAnswer() {
+  const selection = pendingAnswerSelection;
+  if (!selection) return;
+  const liveSelection = selectedAssistantAnswer();
+  if (!liveSelection) {
+    dismissSelectionAskAction();
+    return;
+  }
+  const nextDraft = buildSelectionComposerDraft(liveSelection.text, inputEl.value);
+  if (nextDraft === inputEl.value) {
+    dismissSelectionAskAction();
+    return;
+  }
+  inputEl.value = nextDraft;
+  dismissSelectionAskAction();
+  window.getSelection?.()?.removeAllRanges();
+  handleInput();
+  inputEl.focus();
+  inputEl.setSelectionRange(inputEl.value.length, inputEl.value.length);
+}
+
 function addMessage(role, content, options = {}) {
   const msgEl = document.createElement('div');
   msgEl.className = `message ${role}`;
@@ -11264,6 +11395,11 @@ async function handleGlobalKeydown(e) {
     if (e.isComposing) return;
     const slashMenuOpen = !!slashCommandMenuEl && !slashCommandMenuEl.classList.contains('hidden');
     if (slashMenuOpen) return;
+    if (selectionAskActionEl && !selectionAskActionEl.classList.contains('hidden')) {
+      e.preventDefault();
+      dismissSelectionAskAction();
+      return;
+    }
     // Provider/language pickers close on Escape in bubble/target handlers; do not
     // abort the active run while those listboxes are open.
     const providerPickerOpen = !!providerPickerMenu && !providerPickerMenu.classList.contains('hidden');
@@ -12168,6 +12304,26 @@ if (attachBtn && fileAttachInput) {
 
 // --- Event Listeners ---
 
+if (selectionAskActionEl) {
+  selectionAskActionEl.addEventListener('mousedown', (event) => event.preventDefault());
+  selectionAskActionEl.addEventListener('click', (event) => {
+    event.stopPropagation();
+    askAboutSelectedAnswer();
+  });
+  document.addEventListener('selectionchange', scheduleSelectionAskActionRefresh);
+  document.addEventListener('pointerdown', handleSelectionAskPointerDown);
+  document.addEventListener('pointerup', handleSelectionAskPointerUp);
+  document.addEventListener('pointercancel', handleSelectionAskPointerUp);
+  document.addEventListener('keyup', scheduleSelectionAskActionRefresh);
+  chatContainerEl?.addEventListener('scroll', dismissSelectionAskAction, { passive: true });
+  window.addEventListener('resize', dismissSelectionAskAction);
+  document.addEventListener('wb-locale-changed', () => {
+    selectionAskActionLocale = '';
+    applySelectionAskActionLabel();
+    scheduleSelectionAskActionRefresh();
+  });
+}
+
 sendBtn.addEventListener('click', sendMessage);
 
 document.addEventListener('keydown', handleGlobalKeydown, true);
diff --git a/src/firefox/styles/sidepanel.css b/src/firefox/styles/sidepanel.css
index f71ddc2de..244326f59 100644
--- a/src/firefox/styles/sidepanel.css
+++ b/src/firefox/styles/sidepanel.css
@@ -2147,6 +2147,8 @@ body {
   font-size: 10px;
   font-weight: 700;
   line-height: 1.2;
+  overflow: hidden;
+  text-overflow: ellipsis;
   white-space: nowrap;
 }
 
@@ -2174,6 +2176,39 @@ body {
   opacity: 0.48;
 }
 
+.selection-ask-action {
+  position: fixed;
+  z-index: 30;
+  max-width: calc(100vw - 16px);
+  padding: 6px 10px;
+  border: 1px solid color-mix(in srgb, var(--accent) 45%, var(--border));
+  border-radius: 999px;
+  background: var(--bg-secondary);
+  box-shadow: 0 5px 16px color-mix(in srgb, var(--text-primary) 18%, transparent);
+  color: var(--text-primary);
+  cursor: pointer;
+  font: inherit;
+  font-size: 11px;
+  font-weight: 700;
+  line-height: 1.2;
+  user-select: none;
+  white-space: nowrap;
+}
+
+.selection-ask-action.hidden {
+  display: none;
+}
+
+.selection-ask-action:hover {
+  border-color: var(--accent);
+  background: var(--accent-dim);
+}
+
+.selection-ask-action:focus-visible {
+  outline: 3px solid color-mix(in srgb, var(--accent) 34%, transparent);
+  outline-offset: 2px;
+}
+
 
 
 /* Context-aware recommendations — inline centered pill row in the chat body */
diff --git a/test/run.js b/test/run.js
index 2acb0ed09..ec0145a18 100644
--- a/test/run.js
+++ b/test/run.js
@@ -1124,6 +1124,48 @@ const {
   'file://' + path.join(ROOT, 'src/firefox/src/agent/sheets-tools.js').replace(/\\/g, '/')
 );
 
+const {
+  buildSelectionQuote,
+  buildSelectionComposerDraft,
+  selectionIsQuoteable,
+  selectionTextFromContents,
+  isSelectionQuoteChrome,
+} = await import(
+  'file://' + path.join(ROOT, 'src/chrome/src/ui/selection-quote.js').replace(/\\/g, '/')
+);
+const {
+  buildSelectionQuote: buildSelectionQuoteFx,
+  buildSelectionComposerDraft: buildSelectionComposerDraftFx,
+  selectionIsQuoteable: selectionIsQuoteableFx,
+  selectionTextFromContents: selectionTextFromContentsFx,
+  isSelectionQuoteChrome: isSelectionQuoteChromeFx,
+} = await import(
+  'file://' + path.join(ROOT, 'src/firefox/src/ui/selection-quote.js').replace(/\\/g, '/')
+);
+const sidepanelSources = [
+  fs.readFileSync(path.join(ROOT, 'src/chrome/src/ui/sidepanel.js'), 'utf8'),
+  fs.readFileSync(path.join(ROOT, 'src/firefox/src/ui/sidepanel.js'), 'utf8'),
+];
+const sidepanelHtmlSources = [
+  fs.readFileSync(path.join(ROOT, 'src/chrome/src/ui/sidepanel.html'), 'utf8'),
+  fs.readFileSync(path.join(ROOT, 'src/firefox/src/ui/sidepanel.html'), 'utf8'),
+];
+const sidepanelStyleSources = [
+  fs.readFileSync(path.join(ROOT, 'src/chrome/styles/sidepanel.css'), 'utf8'),
+  fs.readFileSync(path.join(ROOT, 'src/firefox/styles/sidepanel.css'), 'utf8'),
+];
+const selectionQuoteSources = [
+  fs.readFileSync(path.join(ROOT, 'src/chrome/src/ui/selection-quote.js'), 'utf8'),
+  fs.readFileSync(path.join(ROOT, 'src/firefox/src/ui/selection-quote.js'), 'utf8'),
+];
+
+function sourceBetween(source, startMarker, endMarker) {
+  const start = source.indexOf(startMarker);
+  const end = source.indexOf(endMarker, start + startMarker.length);
+  assert.ok(start >= 0 && end > start, `source markers missing: ${startMarker}`);
+  return source.slice(start, end);
+}
+
 // ────────────────────────────────────────────────────────────────────────
 // Test framework (one function, no deps)
 // ────────────────────────────────────────────────────────────────────────
@@ -1131,6 +1173,95 @@ const {
 const tests = [];
 function test(name, fn) { tests.push({ name, fn }); }
 
+console.log('\nselection quote');
+
+test('buildSelectionQuote preserves multiline answer text as an editable quote', () => {
+  const selected = 'First line\n\n<script>alert("x")</script>';
+  const expected = '> First line\n> \n> <script>alert("x")</script>\n\n';
+  assert.equal(buildSelectionQuote(selected), expected);
+  assert.equal(buildSelectionQuoteFx(selected), expected, 'Firefox quote builder should match Chrome');
+  assert.equal(buildSelectionComposerDraft('A detail', 'Why?'), '> A detail\n\nWhy?');
+  assert.equal(buildSelectionComposerDraftFx('A detail', 'Why?'), '> A detail\n\nWhy?', 'Firefox draft builder should match Chrome');
+  assert.equal(buildSelectionComposerDraft('', 'draft'), 'draft');
+  assert.equal(buildSelectionComposerDraft('A detail', '> A detail\n\nWhy?'), '> A detail\n\nWhy?');
+  assert.equal(buildSelectionComposerDraft('A detail', ' '), '> A detail\n\n ');
+});
+
+test('selectionIsQuoteable requires one non-empty assistant answer element', () => {
+  const answer = {};
+  const otherAnswer = {};
+  const valid = { startTextElement: answer, endTextElement: answer, text: 'A detail' };
+  assert.equal(selectionIsQuoteable(valid), true);
+  assert.equal(selectionIsQuoteable({ ...valid, endTextElement: otherAnswer }), false);
+  assert.equal(selectionIsQuoteable({ ...valid, text: ' \n ' }), false);
+  assert.equal(selectionIsQuoteableFx(valid), true, 'Firefox eligibility should match Chrome');
+  assert.equal(selectionIsQuoteableFx({ ...valid, endTextElement: otherAnswer }), false);
+});
+
+test('selection quote helper stays byte-identical across browser builds', () => {
+  assert.equal(selectionQuoteSources[0], selectionQuoteSources[1]);
+});
+
+test('selectionTextFromContents skips in-bubble chrome and keeps answer text', () => {
+  const textNode = (value) => ({ nodeType: 3, nodeValue: value });
+  const element = (tagName, className, ...childNodes) => ({
+    nodeType: 1,
+    tagName,
+    className,
+    classList: { contains: (name) => String(className || '').split(/\s+/).includes(name) },
+    childNodes,
+  });
+  const tree = element(
+    'DIV',
+    'message-text',
+    textNode('Intro '),
+    element('DIV', 'code-block-wrapper',
+      element('DIV', 'code-block-header',
+        element('SPAN', 'code-lang', textNode('javascript')),
+        element('BUTTON', 'code-copy-btn', textNode('Copy')),
+      ),
+      element('PRE', '', element('CODE', '', textNode('const x = 1;'))),
+    ),
+    element('BR', ''),
+    textNode('Outro'),
+  );
+  const expected = 'Intro const x = 1;\nOutro';
+  assert.equal(selectionTextFromContents(tree), expected);
+  assert.equal(selectionTextFromContentsFx(tree), expected, 'Firefox chrome-stripping should match Chrome');
+  assert.equal(isSelectionQuoteChrome(element('BUTTON', 'code-copy-btn', textNode('Copy'))), true);
+  assert.equal(isSelectionQuoteChromeFx(element('SPAN', 'code-lang', textNode('javascript'))), true);
+  assert.equal(isSelectionQuoteChrome(element('CODE', '', textNode('const x = 1;'))), false);
+});
+
+test('selection answer action wiring covers show, dismiss, and tab/conversation changes in both sidepanels', () => {
+  for (const [index, source] of sidepanelSources.entries()) {
+    const switchToTabSource = sourceBetween(source, 'async function switchToTab', '\n}\n\nasync function refreshVisibleSidePanelState');
+    const clearConversationSource = sourceBetween(source, 'async function renderClearedConversationForTab', '\nconst TOOL_KEYS =');
+    const sendMessageSource = sourceBetween(source, 'async function sendMessage', '\nasync function continueAgent');
+    assert.match(source, /document\.addEventListener\('selectionchange', scheduleSelectionAskActionRefresh\)/);
+    assert.match(source, /document\.addEventListener\('pointerdown', handleSelectionAskPointerDown\)/);
+    assert.match(source, /document\.addEventListener\('pointerup', handleSelectionAskPointerUp\)/);
+    assert.match(source, /document\.addEventListener\('pointercancel', handleSelectionAskPointerUp\)/);
+    assert.match(source, /document\.addEventListener\('keyup', scheduleSelectionAskActionRefresh\)/);
+    assert.match(source, /if \(!force && selectionAskPointerDown\) return;/);
+    assert.match(source, /const text = selectionTextFromRange\(range\);/);
+    assert.match(source, /function applySelectionAskActionLabel\(\)/);
+    assert.match(source, /if \(selectionAskActionLocale === locale && selectionAskActionLabel[\s\S]*?selectionAskActionEl\.textContent === selectionAskActionLabel\)/);
+    assert.match(source, /selectionAskActionEl\.addEventListener\('click'/);
+    assert.match(source, /if \(!rect\.width && !rect\.height\) \{[\s\S]*?dismissSelectionAskAction\(\);/);
+    assert.match(source, /if \(!range\.startContainer\.isConnected \|\| !range\.endContainer\.isConnected\) return null;/);
+    assert.match(source, /const liveSelection = selectedAssistantAnswer\(\);/);
+    assert.match(source, /selectionAskActionEl && !selectionAskActionEl\.classList\.contains\('hidden'\)[\s\S]*?dismissSelectionAskAction\(\);/);
+    assert.match(switchToTabSource, /dismissSelectionAskAction\(\);/);
+    assert.match(clearConversationSource, /dismissSelectionAskAction\(\);/);
+    assert.match(sendMessageSource, /dismissSelectionAskAction\(\);/);
+    assert.match(source, /dismissSelectionAskAction\(\);\s*return;/);
+    assert.match(sidepanelHtmlSources[index], /id="selection-ask-action"/);
+    assert.doesNotMatch(sidepanelHtmlSources[index], /id="selection-ask-action"[^>]*aria-live/);
+    assert.match(sidepanelStyleSources[index], /\.selection-ask-action \{[\s\S]*?user-select:\s*none;/);
+  }
+});
+
 console.log('\nscreenshot redaction');
 
 test('selectRedactionRegions blurs password fields always', () => {