feat: add fusion for multi-run sessions

Adds Run fusion for multi-run-like sessions
Combines sibling outputs into a new fusion session
Adds configurable Fusion prompts in Magic Prompts settings

packages/ui/src/components/icons/FusionIcon.tsx

@@ -0,0 +1,31 @@
+import type { SVGProps } from 'react';
+
+export function FusionIcon(props: SVGProps<SVGSVGElement>) {
+  return (
+    <svg
+      xmlns="http://www.w3.org/2000/svg"
+      viewBox="0 0 24 24"
+      fill="none"
+      aria-hidden="true"
+      {...props}
+    >
+      <path
+        d="M12 4.5v6.25M12 10.75v3.5M12 10.75H7.25A3.25 3.25 0 0 0 4 14v1.25M12 10.75h4.75A3.25 3.25 0 0 1 20 14v1.25"
+        stroke="currentColor"
+        strokeWidth="1.65"
+        strokeLinecap="round"
+        strokeLinejoin="round"
+      />
+      <path
+        d="M9.25 7.25 12 4.5l2.75 2.75"
+        stroke="currentColor"
+        strokeWidth="1.65"
+        strokeLinecap="round"
+        strokeLinejoin="round"
+      />
+      <circle cx="4" cy="17.25" r="1.55" stroke="currentColor" strokeWidth="1.65" />
+      <circle cx="12" cy="17.25" r="1.55" stroke="currentColor" strokeWidth="1.65" />
+      <circle cx="20" cy="17.25" r="1.55" stroke="currentColor" strokeWidth="1.65" />
+    </svg>
+  );
+}

packages/ui/src/components/multirun/AgentSelector.tsx

@@ -22,6 +22,8 @@ export interface AgentSelectorProps {
   disabled?: boolean;
   /** ID for accessibility */
   id?: string;
+  /** Portal menu to body instead of nearest dialog. */
+  portalToBody?: boolean;
 }
 
 /**
@@ -34,6 +36,7 @@ export const AgentSelector: React.FC<AgentSelectorProps> = ({
   className,
   disabled,
   id,
+  portalToBody,
 }) => {
   const { t } = useI18n();
   const getVisibleAgents = useConfigStore((state) => state.getVisibleAgents);
@@ -95,7 +98,7 @@ export const AgentSelector: React.FC<AgentSelectorProps> = ({
       >
         <SelectValue placeholder={t('multirun.agentSelector.placeholder')} />
       </SelectTrigger>
-      <SelectContent fitContent>
+      <SelectContent fitContent portalToBody={portalToBody}>
         {selectableAgents.length > 0 && (
           <SelectGroup>
             {selectableAgents.map((agent) => (

packages/ui/src/components/multirun/ModelMultiSelect.tsx

@@ -100,6 +100,14 @@ export interface ModelMultiSelectProps {
   maxModels?: number;
   /** Optional className for add model trigger button */
   addButtonClassName?: string;
+  /** Direction for the model picker popup. Multi-run launcher opens upward near the footer. */
+  dropdownSide?: 'top' | 'bottom';
+  /** Optional className for the picker popup. */
+  dropdownClassName?: string;
+  /** Optional className for the trigger/dropdown positioning container. */
+  containerClassName?: string;
+  /** Optional trigger icon override. */
+  triggerIcon?: React.ReactNode;
 }
 
 /**
@@ -115,6 +123,10 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
   showChips = true,
   maxModels,
   addButtonClassName,
+  dropdownSide = 'top',
+  dropdownClassName,
+  containerClassName,
+  triggerIcon,
 }) => {
   const { t } = useI18n();
   const providers = useConfigStore((state) => state.providers);
@@ -128,7 +140,8 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
   const dropdownRef = React.useRef<HTMLDivElement>(null);
   const triggerRef = React.useRef<HTMLButtonElement>(null);
   const itemRefs = React.useRef<(HTMLButtonElement | null)[]>([]);
-  const canAddModel = maxModels === undefined || selectedModels.length < maxModels;
+  const isSingleSelect = maxModels === 1;
+  const canAddModel = maxModels === undefined || selectedModels.length < maxModels || isSingleSelect;
 
   // Count occurrences of each model for display purposes
   const modelCounts = React.useMemo(() => {
@@ -208,12 +221,21 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
 
   const hasResults = filteredFavorites.length > 0 || filteredRecents.length > 0 || filteredProviders.length > 0;
 
-  // Calculate available height: space above trigger within visible area
+  // Calculate available height: multi-run opens upward inside a scroller; fusion opens downward and may extend past the dialog.
   React.useEffect(() => {
     if (!isOpen || !triggerRef.current) return;
 
     const triggerRect = triggerRef.current.getBoundingClientRect();
 
+    if (dropdownSide === 'bottom') {
+      const viewportHeight = window.visualViewport?.height ?? document.documentElement.clientHeight ?? window.innerHeight;
+      const spaceBelow = viewportHeight - triggerRect.bottom - 16;
+      // availableHeight is only the scrollable model list; reserve room for search + keyboard hint chrome.
+      const listSpaceBelow = spaceBelow - 112;
+      setAvailableHeight(Math.max(160, Math.min(320, listSpaceBelow)));
+      return;
+    }
+
     // Find the nearest dialog or overflow ancestor to constrain within
     let container: HTMLElement | null = triggerRef.current.parentElement;
     while (container) {
@@ -231,7 +253,7 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
     const spaceAbove = triggerRect.top - topBound - 16;
     // Cap: min 150, max 300
     setAvailableHeight(Math.max(150, Math.min(300, spaceAbove)));
-  }, [isOpen]);
+  }, [dropdownSide, isOpen]);
 
   // Focus search input when opened
   React.useEffect(() => {
@@ -292,12 +314,27 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
         type="button"
         disabled={!canAddModel}
         onClick={() => {
-          onAdd({
+          const nextModel = {
             providerID,
             modelID,
             displayName: (model.name as string) || modelID,
             instanceId: generateInstanceId(),
+          };
+          if (isSingleSelect && selectedModels.length > 0 && onUpdate) {
+            onUpdate(0, nextModel);
+            setIsOpen(false);
+            setSearchQuery('');
+            setSelectedIndex(0);
+            return;
+          }
+          onAdd({
+            ...nextModel,
           });
+          if (isSingleSelect) {
+            setIsOpen(false);
+            setSearchQuery('');
+            setSelectedIndex(0);
+          }
           // Don't close dropdown - allow selecting multiple
         }}
         onMouseEnter={() => setSelectedIndex(flatIndex)}
@@ -333,7 +370,7 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
     <div className="space-y-2">
       <div className="flex flex-wrap gap-1.5 items-center">
         {/* Add model button (dropdown trigger) */}
-        <div className="relative" ref={dropdownRef}>
+        <div className={cn('relative', containerClassName)} ref={dropdownRef}>
           <Button
             ref={triggerRef}
             type="button"
@@ -349,7 +386,7 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
               setIsOpen(!isOpen);
             }}
           >
-            <Icon name="add" className="h-3.5 w-3.5 mr-1" />
+            {triggerIcon ?? <Icon name="add" className="h-3.5 w-3.5 mr-1" />}
             {addButtonLabel ?? t('multirun.modelMultiSelect.actions.addModel')}
           </Button>
 
@@ -398,12 +435,22 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
                 e.stopPropagation();
                 const selectedItem = flatModelList[selectedIndex];
                 if (selectedItem && canAddModel) {
-                  onAdd({
+                  const nextModel = {
                     providerID: selectedItem.providerID,
                     modelID: selectedItem.modelID,
                     displayName: (selectedItem.model.name as string) || selectedItem.modelID,
                     instanceId: generateInstanceId(),
-                  });
+                  };
+                  if (isSingleSelect && selectedModels.length > 0 && onUpdate) {
+                    onUpdate(0, nextModel);
+                  } else {
+                    onAdd(nextModel);
+                  }
+                  if (isSingleSelect) {
+                    setIsOpen(false);
+                    setSearchQuery('');
+                    setSelectedIndex(0);
+                  }
                 }
               } else if (e.key === 'Escape') {
                 e.preventDefault();
@@ -418,7 +465,11 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
 
             return (
               <div
-                className="absolute bottom-full left-0 mb-1 z-50 w-[min(380px,calc(100vw-2rem))] max-w-[calc(100vw-2rem)] flex flex-col overflow-hidden rounded-xl border border-border/50 shadow-lg"
+                className={cn(
+                  'absolute left-0 z-50 w-[min(420px,calc(100vw-2rem))] max-w-[calc(100vw-2rem)] flex flex-col overflow-hidden rounded-xl border border-border/50 shadow-lg',
+                  dropdownSide === 'top' ? 'bottom-full mb-1' : 'top-full mt-1',
+                  dropdownClassName,
+                )}
                 style={{
                   background: 'linear-gradient(var(--surface-elevated),var(--surface-elevated)),linear-gradient(var(--surface-background),var(--surface-background))',
                 }}

packages/ui/src/components/multirun/MultiRunFusionDialog.tsx

@@ -0,0 +1,259 @@
+import React from 'react';
+import type { Session } from '@opencode-ai/sdk/v2/client';
+import { toast } from '@/components/ui';
+import { Button } from '@/components/ui/button';
+import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle } from '@/components/ui/dialog';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+import { Icon } from '@/components/icon/Icon';
+import { ProviderLogo } from '@/components/ui/ProviderLogo';
+import { useI18n } from '@/lib/i18n';
+import { opencodeClient } from '@/lib/opencode/client';
+import { useConfigStore } from '@/stores/useConfigStore';
+import { resolveGlobalSessionDirectory, useGlobalSessionsStore } from '@/stores/useGlobalSessionsStore';
+import { useSessionUIStore } from '@/sync/session-ui-store';
+import { useAllLiveSessions } from '@/sync/sync-context';
+import { getSyncMessages, getSyncParts } from '@/sync/sync-refs';
+import { flattenAssistantTextParts } from '@/lib/messages/messageText';
+import { getFusionSessionTitle, parseMultiRunSessionTitle } from '@/lib/multirun/title';
+import { renderMagicPrompt } from '@/lib/magicPrompts';
+import { AgentSelector } from './AgentSelector';
+import { ModelMultiSelect, generateInstanceId, type ModelSelectionWithId } from './ModelMultiSelect';
+
+type FusionSource = {
+  session: Session;
+  directory: string | null;
+  projectDirectory: string | null;
+};
+
+const buildSourcePart = (source: FusionSource, text: string, index: number): string => {
+  const title = source.session.title?.trim() || source.session.id;
+  return `\n\n--- RESULT ${index + 1}: ${title} ---\n${text.trim()}\n--- END RESULT ${index + 1} ---`;
+};
+
+const getSessionProjectDirectory = (sessionId: string, directory: string | null): string | null => {
+  const metadata = useSessionUIStore.getState().getWorktreeMetadata(sessionId);
+  return metadata?.projectDirectory ?? directory;
+};
+
+const getLastAssistantText = async (source: FusionSource): Promise<string> => {
+  const directory = source.directory ?? undefined;
+  const messages = getSyncMessages(source.session.id, directory);
+
+  if (messages.length === 0 && source.directory) {
+    const result = await opencodeClient.withDirectory(source.directory, () =>
+      opencodeClient.getSdkClient().session.messages({
+        sessionID: source.session.id,
+        directory: source.directory ?? undefined,
+        limit: 50,
+      })
+    );
+    const records = result.data ?? [];
+    for (let index = records.length - 1; index >= 0; index -= 1) {
+      const record = records[index] as { info?: { role?: string }; parts?: unknown[] };
+      if (record.info?.role !== 'assistant') continue;
+      return flattenAssistantTextParts((record.parts ?? []) as Parameters<typeof flattenAssistantTextParts>[0]).trim();
+    }
+    return '';
+  }
+
+  for (let index = messages.length - 1; index >= 0; index -= 1) {
+    const message = messages[index];
+    if (message.role !== 'assistant') continue;
+    return flattenAssistantTextParts(getSyncParts(message.id, directory)).trim();
+  }
+
+  return '';
+};
+
+export function MultiRunFusionDialog({
+  session,
+  open,
+  onOpenChange,
+}: {
+  session: Session;
+  open: boolean;
+  onOpenChange: (open: boolean) => void;
+}) {
+  const { t } = useI18n();
+  const liveSessions = useAllLiveSessions();
+  const activeSessions = useGlobalSessionsStore((state) => state.activeSessions);
+  const archivedSessions = useGlobalSessionsStore((state) => state.archivedSessions);
+  const providers = useConfigStore((state) => state.providers);
+  const currentProviderId = useConfigStore((state) => state.currentProviderId);
+  const currentModelId = useConfigStore((state) => state.currentModelId);
+  const currentAgentName = useConfigStore((state) => state.currentAgentName);
+  const [providerID, setProviderID] = React.useState(currentProviderId ?? '');
+  const [modelID, setModelID] = React.useState(currentModelId ?? '');
+  const [selectedModelSelection, setSelectedModelSelection] = React.useState<ModelSelectionWithId[]>(() => (
+    currentProviderId && currentModelId
+      ? [{ providerID: currentProviderId, modelID: currentModelId, instanceId: generateInstanceId() }]
+      : []
+  ));
+  const [variant, setVariant] = React.useState<string>('');
+  const [agent, setAgent] = React.useState(currentAgentName ?? '');
+  const [sources, setSources] = React.useState<FusionSource[]>([]);
+  const [isStarting, setIsStarting] = React.useState(false);
+
+  const parsed = React.useMemo(() => parseMultiRunSessionTitle(session.title), [session.title]);
+  const allSessions = React.useMemo(() => {
+    const byId = new Map<string, Session>();
+    for (const candidate of liveSessions) byId.set(candidate.id, candidate);
+    for (const candidate of activeSessions) byId.set(candidate.id, candidate);
+    for (const candidate of archivedSessions) byId.set(candidate.id, candidate);
+    if (session.id) byId.set(session.id, session);
+    return Array.from(byId.values());
+  }, [activeSessions, archivedSessions, liveSessions, session]);
+
+  React.useEffect(() => {
+    if (!open || !parsed) return;
+
+    const currentDirectory = useSessionUIStore.getState().getDirectoryForSession(session.id);
+    const currentProjectDirectory = getSessionProjectDirectory(session.id, currentDirectory);
+    const nextSources = allSessions
+      .map((candidate): FusionSource | null => {
+        const candidateParsed = parseMultiRunSessionTitle(candidate.title);
+        if (!candidateParsed || candidateParsed.groupSlug !== parsed.groupSlug || candidateParsed.fusion) return null;
+        const directory = useSessionUIStore.getState().getDirectoryForSession(candidate.id)
+          ?? resolveGlobalSessionDirectory(candidate);
+        const projectDirectory = getSessionProjectDirectory(candidate.id, directory);
+        if (currentProjectDirectory && projectDirectory && currentProjectDirectory !== projectDirectory) return null;
+        return { session: candidate, directory, projectDirectory };
+      })
+      .filter((source): source is FusionSource => source !== null)
+      .sort((a, b) => (a.session.time?.created ?? 0) - (b.session.time?.created ?? 0));
+
+    setSources(nextSources);
+  }, [allSessions, open, parsed, session.id]);
+
+  const selectedProvider = providers.find((provider) => provider.id === providerID);
+  const selectedProviderModel = selectedProvider?.models.find((model) => model.id === modelID) as { variants?: Record<string, unknown> } | undefined;
+  const variantKeys = selectedProviderModel?.variants ? Object.keys(selectedProviderModel.variants) : [];
+  const canStart = Boolean(parsed && providerID && modelID && sources.length > 0 && !isStarting);
+
+  const handleModelSelect = React.useCallback((model: ModelSelectionWithId) => {
+    setSelectedModelSelection([model]);
+    setProviderID(model.providerID);
+    setModelID(model.modelID);
+    setVariant('');
+  }, []);
+
+  const selectedModelLabel = selectedModelSelection[0]?.displayName || selectedModelSelection[0]?.modelID || t('multirun.fusion.model.placeholder');
+
+  const handleStart = async () => {
+    if (!parsed || !providerID || !modelID) return;
+    setIsStarting(true);
+    try {
+      const sourceTexts = await Promise.all(sources.map((source) => getLastAssistantText(source)));
+      const usableSources = sources
+        .map((source, index) => ({ source, text: sourceTexts[index] ?? '' }))
+        .filter((item) => item.text.trim().length > 0);
+
+      if (usableSources.length === 0) {
+        toast.error(t('multirun.fusion.toast.noOutputs'));
+        return;
+      }
+
+      const directory = sources[0]?.projectDirectory ?? sources[0]?.directory ?? null;
+      const fusionTitle = getFusionSessionTitle(parsed.groupSlug, providerID, modelID);
+      const [visiblePrompt, instructionsPrompt] = await Promise.all([
+        renderMagicPrompt('session.fusion.visible'),
+        renderMagicPrompt('session.fusion.instructions'),
+      ]);
+      const fusionSession = await useSessionUIStore.getState().createSession(fusionTitle, directory, null);
+      if (!fusionSession) throw new Error('Failed to create fusion session');
+
+      useSessionUIStore.getState().setCurrentSession(fusionSession.id, directory);
+      onOpenChange(false);
+
+      await opencodeClient.withDirectory(directory ?? opencodeClient.getDirectory(), () =>
+        opencodeClient.sendMessage({
+          id: fusionSession.id,
+          providerID,
+          modelID,
+          variant: variant || undefined,
+          agent: agent || undefined,
+          text: visiblePrompt,
+          additionalParts: [
+            { text: instructionsPrompt, synthetic: true },
+            ...usableSources.map((item, index) => ({ text: buildSourcePart(item.source, item.text, index), synthetic: true })),
+            { text: '\n\n--- FUSION INPUTS END ---\nNow write the final fused answer.', synthetic: true },
+          ],
+        })
+      );
+    } catch (error) {
+      console.error('[MultiRunFusion] Failed to start fusion', error);
+      toast.error(t('multirun.fusion.toast.failed'));
+    } finally {
+      setIsStarting(false);
+    }
+  };
+
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent className="max-w-xl overflow-visible">
+        <DialogHeader>
+          <DialogTitle>{t('multirun.fusion.title')}</DialogTitle>
+          <DialogDescription>{t('multirun.fusion.description')}</DialogDescription>
+        </DialogHeader>
+
+        <div className="flex flex-wrap items-center gap-2">
+          <div className="max-w-full">
+            <ModelMultiSelect
+              selectedModels={selectedModelSelection}
+              onAdd={handleModelSelect}
+              onUpdate={(_, model) => handleModelSelect(model)}
+              onRemove={() => {
+                setSelectedModelSelection([]);
+                setProviderID('');
+                setModelID('');
+                setVariant('');
+              }}
+              maxModels={1}
+              addButtonLabel={selectedModelLabel}
+              showChips={false}
+              addButtonClassName="h-8 w-fit max-w-[min(28rem,calc(100vw-8rem))] justify-start rounded-[9px] [corner-shape:squircle] supports-[corner-shape:squircle]:rounded-[50px] px-3 py-1.5"
+              dropdownSide="bottom"
+              dropdownClassName="w-[min(28rem,calc(100vw-8rem))]"
+              triggerIcon={providerID ? <ProviderLogo providerId={providerID} className="h-3.5 w-3.5 mr-1" /> : undefined}
+            />
+          </div>
+
+          {variantKeys.length > 0 ? (
+            <Select value={variant || '__default__'} onValueChange={(value) => setVariant(value === '__default__' ? '' : value)}>
+              <SelectTrigger size="lg" className="h-8 w-fit rounded-[9px] [corner-shape:squircle] supports-[corner-shape:squircle]:rounded-[50px] !border-border/80 !bg-[var(--surface-subtle)] hover:!bg-[var(--interactive-hover)]/70 typography-meta font-medium text-foreground px-3 py-1.5">
+                <Icon name="brain-ai-3" className="h-3.5 w-3.5 text-muted-foreground" />
+                <SelectValue>{(value) => value === '__default__' ? t('multirun.modelMultiSelect.variant.default') : value}</SelectValue>
+              </SelectTrigger>
+              <SelectContent fitContent portalToBody>
+                <SelectItem value="__default__">{t('multirun.modelMultiSelect.variant.default')}</SelectItem>
+                {variantKeys.map((key) => <SelectItem key={key} value={key}>{key}</SelectItem>)}
+              </SelectContent>
+            </Select>
+          ) : null}
+
+          <AgentSelector value={agent} onChange={setAgent} portalToBody className="h-8 rounded-[9px] [corner-shape:squircle] supports-[corner-shape:squircle]:rounded-[50px] px-3 py-1.5" />
+        </div>
+
+        <div className="space-y-2">
+          <div className="typography-meta font-medium text-foreground">{t('multirun.fusion.sources.label', { count: sources.length })}</div>
+          <div className="max-h-56 space-y-1 overflow-auto rounded-lg border border-[var(--interactive-border)] p-1">
+            {sources.map((source) => (
+              <div key={source.session.id} className="flex items-center gap-2 rounded-md px-2 py-1.5 typography-meta">
+                <ProviderLogo providerId={parseMultiRunSessionTitle(source.session.title)?.providerID ?? ''} className="h-4 w-4" />
+                <span className="min-w-0 flex-1 truncate">{source.session.title || source.session.id}</span>
+                <button type="button" onClick={() => setSources((prev) => prev.filter((item) => item.session.id !== source.session.id))} className="text-muted-foreground hover:text-foreground">
+                  <Icon name="close" className="h-4 w-4" />
+                </button>
+              </div>
+            ))}
+          </div>
+        </div>
+
+        <DialogFooter>
+          <Button variant="ghost" onClick={() => onOpenChange(false)}>{t('multirun.fusion.actions.cancel')}</Button>
+          <Button onClick={handleStart} disabled={!canStart}>{isStarting ? t('multirun.fusion.actions.starting') : t('multirun.fusion.actions.start')}</Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  );
+}

packages/ui/src/components/sections/magic-prompts/MagicPromptsPage.tsx

@@ -140,6 +140,14 @@ const PROMPT_PAGE_MAP: Record<string, PromptPageConfig> = {
       { id: 'session.review.instructions', titleKey: 'settings.magicPrompts.page.block.instructions' },
     ],
   },
+  'session.fusion': {
+    titleKey: 'settings.magicPrompts.page.group.sessionFusion.title',
+    descriptionKey: 'settings.magicPrompts.page.group.sessionFusion.description',
+    blocks: [
+      { id: 'session.fusion.visible', titleKey: 'settings.magicPrompts.page.block.visiblePrompt' },
+      { id: 'session.fusion.instructions', titleKey: 'settings.magicPrompts.page.block.instructions' },
+    ],
+  },
 };
 
 const hasOwn = (input: Record<string, string>, key: string) => Object.prototype.hasOwnProperty.call(input, key);

packages/ui/src/components/sections/magic-prompts/MagicPromptsSidebar.tsx

@@ -47,6 +47,7 @@ export const MagicPromptsSidebar: React.FC<MagicPromptsSidebarProps> = ({ onItem
         items: [
           { id: 'session.summary', titleKey: 'settings.magicPrompts.sidebar.item.sessionSummary' },
           { id: 'session.review', titleKey: 'settings.magicPrompts.sidebar.item.sessionWorkspaceReview' },
+          { id: 'session.fusion', titleKey: 'settings.magicPrompts.sidebar.item.sessionFusion' },
         ],
       },
     ] as const;

packages/ui/src/components/session/sidebar/SessionNodeItem.tsx

@@ -29,6 +29,9 @@ import { useSessionDisplayStore } from '@/stores/useSessionDisplayStore';
 import { useSessionUnseenCount } from '@/sync/notification-store';
 import { useSessionMultiSelectStore } from '@/stores/useSessionMultiSelectStore';
 import { useI18n } from '@/lib/i18n';
+import { parseMultiRunSessionTitle } from '@/lib/multirun/title';
+import { MultiRunFusionDialog } from '@/components/multirun/MultiRunFusionDialog';
+import { FusionIcon } from '@/components/icons/FusionIcon';
 
 type Folder = { id: string; name: string; sessionIds: string[] };
 
@@ -319,6 +322,8 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
   const sessionUpdatedLabel = formatSessionDateLabel(sessionTimestamp);
   const sessionCompactUpdatedLabel = formatSessionCompactDateLabel(sessionTimestamp);
   const isMenuOpen = openSidebarMenuKey === menuInstanceKey;
+  const isMultiRunLikeSession = React.useMemo(() => parseMultiRunSessionTitle(resolvedSession.title) !== null, [resolvedSession.title]);
+  const [fusionDialogOpen, setFusionDialogOpen] = React.useState(false);
 
   const descendantCount = React.useMemo(() => collectNodeDescendantIds(node).length, [collectNodeDescendantIds, node]);
 
@@ -670,6 +675,12 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
         <Icon name="download" className="mr-1 h-4 w-4" />
         {t('sessions.sidebar.session.menu.exportMarkdown')}
       </DropdownMenuItem>
+      {isMultiRunLikeSession ? (
+        <DropdownMenuItem onClick={() => setFusionDialogOpen(true)} className="[&>svg]:mr-1">
+          <FusionIcon className="mr-1 h-4 w-4" />
+          {t('sessions.sidebar.session.menu.runFusion')}
+        </DropdownMenuItem>
+      ) : null}
 
       {sessionDirectory && !archivedBucket ? (() => {
         const scopeFolders = getFoldersForScope(sessionDirectory);
@@ -980,6 +991,13 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
           </DialogFooter>
         </DialogContent>
       </Dialog>
+      {isMultiRunLikeSession ? (
+        <MultiRunFusionDialog
+          session={resolvedSession}
+          open={fusionDialogOpen}
+          onOpenChange={setFusionDialogOpen}
+        />
+      ) : null}
     </React.Fragment>
   );
 }

packages/ui/src/components/ui/select.tsx

@@ -155,6 +155,7 @@ function SelectTrigger({
 type SelectContentExtra = {
   position?: "popper" | "item-aligned";
   fitContent?: boolean;
+  portalToBody?: boolean;
   sideOffset?: number;
   side?: "top" | "right" | "bottom" | "left";
   align?: "start" | "center" | "end";
@@ -165,6 +166,7 @@ function SelectContent({
   children,
   position = "popper",
   fitContent = false,
+  portalToBody = false,
   sideOffset,
   side,
   align,
@@ -175,13 +177,13 @@ function SelectContent({
   const portalContainer = portalContext?.portalContainer ?? null;
 
   return (
-    <BaseSelect.Portal container={portalContainer || undefined}>
+    <BaseSelect.Portal container={portalToBody ? undefined : portalContainer || undefined}>
       <BaseSelect.Positioner
         alignItemWithTrigger={alignItemWithTrigger}
         sideOffset={sideOffset}
         side={side}
         align={align}
-        className="z-[120] pointer-events-auto"
+        className="absolute z-[120] pointer-events-auto"
       >
         <BaseSelect.Popup
           data-slot="select-content"

packages/ui/src/lib/i18n/messages/en.settings.ts

@@ -164,6 +164,7 @@ export const settingsDict = {
   'settings.magicPrompts.sidebar.item.planImplement': 'Implement Plan',
   'settings.magicPrompts.sidebar.item.sessionSummary': 'Session Summary',
   'settings.magicPrompts.sidebar.item.sessionWorkspaceReview': 'Workspace Review',
+  'settings.magicPrompts.sidebar.item.sessionFusion': 'Fusion',
   'settings.remoteInstances.sidebar.title': 'Remote Instances',
   'settings.remoteInstances.sidebar.total': 'Total {count}',
   'settings.remoteInstances.sidebar.newSshInstanceName': 'New SSH Instance',
@@ -1541,6 +1542,8 @@ export const settingsDict = {
   'settings.magicPrompts.page.group.sessionSummary.description': 'Prompts used by the /summary slash command: visible user message + hidden instructions. Non-destructive - does not compact session history.',
   'settings.magicPrompts.page.group.sessionWorkspaceReview.title': 'Workspace Review',
   'settings.magicPrompts.page.group.sessionWorkspaceReview.description': 'Prompts used by the /workspace-review slash command: visible user message + hidden instructions. Reviews current workspace changes for high-signal issues only.',
+  'settings.magicPrompts.page.group.sessionFusion.title': 'Fusion',
+  'settings.magicPrompts.page.group.sessionFusion.description': 'Prompts used when combining multi-run outputs into one final answer: visible user message + hidden instructions before source results.',
   'settings.magicPrompts.page.actions.resetting': 'Resetting...',
   'settings.magicPrompts.page.actions.resetAllOverrides': 'Reset All Overrides',
   'settings.magicPrompts.page.actions.resetToDefault': 'Reset to Default',

packages/ui/src/lib/i18n/messages/en.ts

@@ -180,6 +180,16 @@ export const dict = {
   'multirun.modelMultiSelect.validation.minOnly': 'Select at least {min} models.',
   'multirun.modelMultiSelect.validation.minToMax': 'Select from {min} to {max} models.',
   'multirun.agentSelector.placeholder': 'Select an agent',
+  'multirun.fusion.title': 'Run fusion',
+  'multirun.fusion.description': 'Combine the selected multi-run outputs into one stronger answer.',
+  'multirun.fusion.provider.placeholder': 'Provider',
+  'multirun.fusion.model.placeholder': 'Model',
+  'multirun.fusion.sources.label': 'Sources ({count})',
+  'multirun.fusion.actions.cancel': 'Cancel',
+  'multirun.fusion.actions.start': 'Start fusion',
+  'multirun.fusion.actions.starting': 'Starting...',
+  'multirun.fusion.toast.noOutputs': 'No assistant outputs found to fuse.',
+  'multirun.fusion.toast.failed': 'Failed to start fusion.',
   'sessions.sidebar.header.actions.searchSessions': 'Search sessions',
   'sessions.sidebar.header.actions.exitSelection': 'Exit selection',
   'sessions.sidebar.header.actions.selectSessions': 'Select sessions',
@@ -242,6 +252,7 @@ export const dict = {
   'sessions.sidebar.session.menu.copyLink': 'Copy link',
   'sessions.sidebar.session.menu.unshare': 'Unshare',
   'sessions.sidebar.session.menu.exportMarkdown': 'Export Markdown',
+  'sessions.sidebar.session.menu.runFusion': 'Run fusion',
   'sessions.sidebar.session.menu.openInSidePanel': 'Open in Side Panel',
   'sessions.sidebar.session.menu.betaBadge': 'beta',
   'sessions.sidebar.session.menu.label': 'Session menu',

packages/ui/src/lib/i18n/messages/es.settings.ts

@@ -164,6 +164,7 @@ export const settingsDict = {
   "settings.magicPrompts.sidebar.item.planImplement": "Implementar plan",
   "settings.magicPrompts.sidebar.item.sessionSummary": "Resumen de sesión",
   "settings.magicPrompts.sidebar.item.sessionWorkspaceReview": "Revisión del espacio de trabajo",
+  "settings.magicPrompts.sidebar.item.sessionFusion": "Fusion",
   "settings.remoteInstances.sidebar.title": "Instancias remotas",
   "settings.remoteInstances.sidebar.total": "Total {count}",
   "settings.remoteInstances.sidebar.newSshInstanceName": "Nueva instancia SSH",
@@ -1541,6 +1542,8 @@ export const settingsDict = {
   "settings.magicPrompts.page.group.sessionSummary.description": "Prompts usados por el comando /summary: mensaje visible del usuario + instrucciones ocultas. No destructivo: no compacta el historial de la sesión.",
   "settings.magicPrompts.page.group.sessionWorkspaceReview.title": "Revisión del espacio de trabajo",
   "settings.magicPrompts.page.group.sessionWorkspaceReview.description": "Prompts usados por el comando /workspace-review: mensaje visible del usuario + instrucciones ocultas. Revisa los cambios actuales del espacio de trabajo solo para problemas de alta señal.",
+  "settings.magicPrompts.page.group.sessionFusion.title": "Fusion",
+  "settings.magicPrompts.page.group.sessionFusion.description": "Prompts usados para combinar salidas de multi-run en una respuesta final: mensaje visible del usuario + instrucciones ocultas antes de los resultados fuente.",
   "settings.magicPrompts.page.actions.resetting": "Restableciendo...",
   "settings.magicPrompts.page.actions.resetAllOverrides": "Restablecer todas las sobrescrituras",
   "settings.magicPrompts.page.actions.resetToDefault": "Restablecer valores predeterminados",

packages/ui/src/lib/i18n/messages/es.ts

@@ -181,6 +181,16 @@ export const dict: Record<I18nKey, string> = {
   "multirun.modelMultiSelect.validation.minOnly": "Selecciona al menos {min} modelos.",
   "multirun.modelMultiSelect.validation.minToMax": "Selecciona entre {min} y {max} modelos.",
   "multirun.agentSelector.placeholder": "Selecciona un agente",
+  "multirun.fusion.title": "Ejecutar fusion",
+  "multirun.fusion.description": "Combina los resultados seleccionados del multi-run en una respuesta más sólida.",
+  "multirun.fusion.provider.placeholder": "Proveedor",
+  "multirun.fusion.model.placeholder": "Modelo",
+  "multirun.fusion.sources.label": "Fuentes ({count})",
+  "multirun.fusion.actions.cancel": "Cancelar",
+  "multirun.fusion.actions.start": "Iniciar fusion",
+  "multirun.fusion.actions.starting": "Iniciando...",
+  "multirun.fusion.toast.noOutputs": "No se encontraron respuestas del asistente para fusionar.",
+  "multirun.fusion.toast.failed": "No se pudo iniciar fusion.",
   "sessions.sidebar.header.actions.searchSessions": "Buscar sesiones",
   "sessions.sidebar.header.actions.exitSelection": "Salir de selección",
   "sessions.sidebar.header.actions.selectSessions": "Seleccionar sesiones",
@@ -243,6 +253,7 @@ export const dict: Record<I18nKey, string> = {
   "sessions.sidebar.session.menu.copyLink": "Copiar enlace",
   "sessions.sidebar.session.menu.unshare": "Dejar de compartir",
   "sessions.sidebar.session.menu.exportMarkdown": "Exportar Markdown",
+  "sessions.sidebar.session.menu.runFusion": "Ejecutar fusion",
   "sessions.sidebar.session.menu.openInSidePanel": "Abrir en panel lateral",
   "sessions.sidebar.session.menu.betaBadge": "beta",
   "sessions.sidebar.session.menu.label": "Menú de sesión",

packages/ui/src/lib/i18n/messages/ko.settings.ts

@@ -164,6 +164,7 @@ export const settingsDict = {
   'settings.magicPrompts.sidebar.item.planImplement': '계획 구현',
   'settings.magicPrompts.sidebar.item.sessionSummary': '세션 요약',
   'settings.magicPrompts.sidebar.item.sessionWorkspaceReview': '워크스페이스 리뷰',
+  'settings.magicPrompts.sidebar.item.sessionFusion': 'Fusion',
   'settings.remoteInstances.sidebar.title': '원격 인스턴스',
   'settings.remoteInstances.sidebar.total': '총 {count}개',
   'settings.remoteInstances.sidebar.newSshInstanceName': '새 SSH 인스턴스',
@@ -1541,6 +1542,8 @@ export const settingsDict = {
   'settings.magicPrompts.page.group.sessionSummary.description': '/summary slash command에서 사용하는 프롬프트입니다: 표시 사용자 메시지 + 숨겨진 지침. 비파괴적이며 세션 기록을 압축하지 않습니다.',
   'settings.magicPrompts.page.group.sessionWorkspaceReview.title': '워크스페이스 리뷰',
   'settings.magicPrompts.page.group.sessionWorkspaceReview.description': '/workspace-review slash command에서 사용하는 프롬프트입니다: 표시 사용자 메시지 + 숨겨진 지침. 현재 workspace 변경 사항에서 중요한 문제만 리뷰합니다.',
+  'settings.magicPrompts.page.group.sessionFusion.title': 'Fusion',
+  'settings.magicPrompts.page.group.sessionFusion.description': 'multi-run 출력을 하나의 최종 답변으로 결합할 때 사용하는 프롬프트입니다: 보이는 사용자 메시지 + 소스 결과 앞의 숨겨진 지침.',
   'settings.magicPrompts.page.actions.resetting': '초기화 중...',
   'settings.magicPrompts.page.actions.resetAllOverrides': '모든 오버라이드 초기화',
   'settings.magicPrompts.page.actions.resetToDefault': '기본값으로 초기화',

packages/ui/src/lib/i18n/messages/ko.ts

@@ -181,6 +181,16 @@ export const dict: Record<I18nKey, string> = {
   'multirun.modelMultiSelect.validation.minOnly': '모델을 최소 {min}개 선택하세요.',
   'multirun.modelMultiSelect.validation.minToMax': '모델을 {min}~{max}개 선택하세요.',
   'multirun.agentSelector.placeholder': '에이전트 선택',
+  'multirun.fusion.title': 'fusion 실행',
+  'multirun.fusion.description': '선택한 multi-run 출력을 하나의 더 강한 답변으로 결합합니다.',
+  'multirun.fusion.provider.placeholder': 'Provider',
+  'multirun.fusion.model.placeholder': 'Model',
+  'multirun.fusion.sources.label': '소스({count})',
+  'multirun.fusion.actions.cancel': '취소',
+  'multirun.fusion.actions.start': 'fusion 시작',
+  'multirun.fusion.actions.starting': '시작 중...',
+  'multirun.fusion.toast.noOutputs': 'fusion할 어시스턴트 응답을 찾지 못했습니다.',
+  'multirun.fusion.toast.failed': 'fusion을 시작하지 못했습니다.',
   'sessions.sidebar.header.actions.searchSessions': '세션 검색',
   'sessions.sidebar.header.actions.exitSelection': '선택 종료',
   'sessions.sidebar.header.actions.selectSessions': '세션 선택',
@@ -243,6 +253,7 @@ export const dict: Record<I18nKey, string> = {
   'sessions.sidebar.session.menu.copyLink': '링크 복사',
   'sessions.sidebar.session.menu.unshare': '공유 해제',
   'sessions.sidebar.session.menu.exportMarkdown': 'Markdown 내보내기',
+  'sessions.sidebar.session.menu.runFusion': 'fusion 실행',
   'sessions.sidebar.session.menu.openInSidePanel': '사이드 패널에서 열기',
   'sessions.sidebar.session.menu.betaBadge': 'beta',
   'sessions.sidebar.session.menu.label': '세션 메뉴',

packages/ui/src/lib/i18n/messages/pl.settings.ts

@@ -280,6 +280,8 @@ export const settingsDict = {
   'settings.magicPrompts.page.group.sessionSummary.title': 'Podsumowanie Sesji',
   'settings.magicPrompts.page.group.sessionWorkspaceReview.description': 'Prompty używane przez polecenie /workspace-review: widoczna wiadomość użytkownika + ukryte instrukcje. Przegląda zmiany w bieżącym obszarze roboczym tylko pod kątem istotnych problemów.',
   'settings.magicPrompts.page.group.sessionWorkspaceReview.title': 'Przegląd obszaru roboczego',
+  'settings.magicPrompts.page.group.sessionFusion.title': 'Fusion',
+  'settings.magicPrompts.page.group.sessionFusion.description': 'Prompty używane do łączenia wyników multi-run w jedną końcową odpowiedź: widoczna wiadomość użytkownika + ukryte instrukcje przed wynikami źródłowymi.',
   'settings.magicPrompts.page.loading.aria': 'Ładowanie',
   'settings.magicPrompts.page.loading.text': 'Ładowanie Magicznych Promptów...',
   'settings.magicPrompts.page.placeholdersLabel': 'Placeholdery:',
@@ -314,6 +316,7 @@ export const settingsDict = {
   'settings.magicPrompts.sidebar.item.planTodo': 'Planowanie Todo',
   'settings.magicPrompts.sidebar.item.sessionSummary': 'Podsumowanie Sesji',
   'settings.magicPrompts.sidebar.item.sessionWorkspaceReview': 'Przegląd obszaru roboczego',
+  'settings.magicPrompts.sidebar.item.sessionFusion': 'Fusion',
   'settings.magicPrompts.sidebar.title': 'Magiczne Prompty',
   'settings.mcp.page.actions.authorize': 'Autoryzuj',
   'settings.mcp.page.actions.clearAuth': 'Wyczyść autoryzację',

packages/ui/src/lib/i18n/messages/pl.ts

@@ -84,6 +84,7 @@ export const dict: Record<I18nKey, string> = {
   'sessions.sidebar.session.menu.copyLink': 'Kopiuj link',
   'sessions.sidebar.session.menu.unshare': 'Cofnij udostępnienie',
   'sessions.sidebar.session.menu.exportMarkdown': 'Eksportuj Markdown',
+  'sessions.sidebar.session.menu.runFusion': 'Uruchom fusion',
   'sessions.sidebar.session.menu.openInSidePanel': 'Otwórz w panelu bocznym',
   'sessions.sidebar.session.menu.betaBadge': 'beta',
   'sessions.sidebar.session.menu.label': 'Menu sesji',
@@ -256,6 +257,16 @@ export const dict: Record<I18nKey, string> = {
   'multirun.modelMultiSelect.validation.minOnly': 'Wybierz przynajmniej {min} modele.',
   'multirun.modelMultiSelect.validation.minToMax': 'Wybierz od {min} do {max} modeli.',
   'multirun.agentSelector.placeholder': 'Wybierz agenta',
+  'multirun.fusion.title': 'Uruchom fusion',
+  'multirun.fusion.description': 'Połącz wybrane wyniki multi-run w jedną mocniejszą odpowiedź.',
+  'multirun.fusion.provider.placeholder': 'Provider',
+  'multirun.fusion.model.placeholder': 'Model',
+  'multirun.fusion.sources.label': 'Źródła ({count})',
+  'multirun.fusion.actions.cancel': 'Anuluj',
+  'multirun.fusion.actions.start': 'Uruchom fusion',
+  'multirun.fusion.actions.starting': 'Uruchamianie...',
+  'multirun.fusion.toast.noOutputs': 'Nie znaleziono odpowiedzi asystenta do fusion.',
+  'multirun.fusion.toast.failed': 'Nie udało się uruchomić fusion.',
   'sessions.sidebar.session.export.dialog.includeSubtasks': 'Dołącz pod-agentów',
   'sessions.sidebar.session.export.dialog.confirm': 'Eksportuj',
   'sessions.sidebar.session.status.active': 'Sesja aktywna',

packages/ui/src/lib/i18n/messages/pt-BR.settings.ts

@@ -164,6 +164,7 @@ export const settingsDict = {
   "settings.magicPrompts.sidebar.item.planImplement": "Implementar plano",
   "settings.magicPrompts.sidebar.item.sessionSummary": "Resumo de sessão",
   "settings.magicPrompts.sidebar.item.sessionWorkspaceReview": "Revisão do workspace",
+  "settings.magicPrompts.sidebar.item.sessionFusion": "Fusion",
   "settings.remoteInstances.sidebar.title": "Instâncias remotas",
   "settings.remoteInstances.sidebar.total": "Total {count}",
   "settings.remoteInstances.sidebar.newSshInstanceName": "Nova instância SSH",
@@ -1541,6 +1542,8 @@ export const settingsDict = {
   "settings.magicPrompts.page.group.sessionSummary.description": "Prompts usados pelo comando /summary: mensagem visível do usuário + instruções ocultas. Não destrutivo: não compacta o histórico da sessão.",
   "settings.magicPrompts.page.group.sessionWorkspaceReview.title": "Revisão do workspace",
   "settings.magicPrompts.page.group.sessionWorkspaceReview.description": "Prompts usados pelo comando /workspace-review: mensagem visível do usuário + instruções ocultas. Revise apenas problemas importantes nas alterações atuais do workspace.",
+  "settings.magicPrompts.page.group.sessionFusion.title": "Fusion",
+  "settings.magicPrompts.page.group.sessionFusion.description": "Prompts usados para combinar saídas de multi-run em uma resposta final: mensagem visível do usuário + instruções ocultas antes dos resultados de origem.",
   "settings.magicPrompts.page.actions.resetting": "Redefinindo...",
   "settings.magicPrompts.page.actions.resetAllOverrides": "Reiniciar todas as sobrescrituras",
   "settings.magicPrompts.page.actions.resetToDefault": "Reiniciar valores padrões",

packages/ui/src/lib/i18n/messages/pt-BR.ts

@@ -181,6 +181,16 @@ export const dict: Record<I18nKey, string> = {
   "multirun.modelMultiSelect.validation.minOnly": "Selecione ao menos {min} modelos.",
   "multirun.modelMultiSelect.validation.minToMax": "Selecione entre {min} e {max} modelos.",
   "multirun.agentSelector.placeholder": "Selecione um agente",
+  "multirun.fusion.title": "Executar fusion",
+  "multirun.fusion.description": "Combine os resultados selecionados do multi-run em uma resposta mais forte.",
+  "multirun.fusion.provider.placeholder": "Provedor",
+  "multirun.fusion.model.placeholder": "Modelo",
+  "multirun.fusion.sources.label": "Fontes ({count})",
+  "multirun.fusion.actions.cancel": "Cancelar",
+  "multirun.fusion.actions.start": "Iniciar fusion",
+  "multirun.fusion.actions.starting": "Iniciando...",
+  "multirun.fusion.toast.noOutputs": "Nenhuma resposta do assistente encontrada para fusion.",
+  "multirun.fusion.toast.failed": "Falha ao iniciar fusion.",
   "sessions.sidebar.header.actions.searchSessions": "Pesquisar sessões",
   "sessions.sidebar.header.actions.exitSelection": "Sair da seleção",
   "sessions.sidebar.header.actions.selectSessions": "Selecionar sessões",
@@ -243,6 +253,7 @@ export const dict: Record<I18nKey, string> = {
   "sessions.sidebar.session.menu.copyLink": "Copiar link",
   "sessions.sidebar.session.menu.unshare": "Parar de compartilhar",
   "sessions.sidebar.session.menu.exportMarkdown": "Exportar Markdown",
+  "sessions.sidebar.session.menu.runFusion": "Executar fusion",
   "sessions.sidebar.session.menu.openInSidePanel": "Abrir no painel lateral",
   "sessions.sidebar.session.menu.betaBadge": "beta",
   "sessions.sidebar.session.menu.label": "Menu da sessão",

packages/ui/src/lib/i18n/messages/uk.settings.ts

@@ -164,6 +164,7 @@ export const settingsDict = {
   "settings.magicPrompts.sidebar.item.planImplement": "Реалізувати план",
   "settings.magicPrompts.sidebar.item.sessionSummary": "Підсумок сесії",
   "settings.magicPrompts.sidebar.item.sessionWorkspaceReview": "Огляд робочого простору",
+  "settings.magicPrompts.sidebar.item.sessionFusion": "Fusion",
   "settings.remoteInstances.sidebar.title": "Віддалені інстанси",
   "settings.remoteInstances.sidebar.total": "Усього {count}",
   "settings.remoteInstances.sidebar.newSshInstanceName": "Новий інстанс SSH",
@@ -1541,6 +1542,8 @@ export const settingsDict = {
   "settings.magicPrompts.page.group.sessionSummary.description": "Промпти, які використовуються командою /summary: видиме повідомлення користувача + приховані інструкції. Неруйнівний – не стискає історію сесії.",
   "settings.magicPrompts.page.group.sessionWorkspaceReview.title": "Огляд робочого простору",
   "settings.magicPrompts.page.group.sessionWorkspaceReview.description": "Промпти, які використовуються командою /workspace-review: видиме повідомлення користувача + приховані інструкції. Переглядає поточні зміни робочого простору лише для проблем із сильним сигналом.",
+  "settings.magicPrompts.page.group.sessionFusion.title": "Fusion",
+  "settings.magicPrompts.page.group.sessionFusion.description": "Промпти для обʼєднання результатів multi-run в одну фінальну відповідь: видиме повідомлення користувача + приховані інструкції перед результатами джерел.",
   "settings.magicPrompts.page.actions.resetting": "Скидання...",
   "settings.magicPrompts.page.actions.resetAllOverrides": "Скинути всі перевизначення",
   "settings.magicPrompts.page.actions.resetToDefault": "Скинути до замовчування",

packages/ui/src/lib/i18n/messages/uk.ts

@@ -181,6 +181,16 @@ export const dict: Record<I18nKey, string> = {
   "multirun.modelMultiSelect.validation.minOnly": "Виберіть щонайменше моделей: {min}.",
   "multirun.modelMultiSelect.validation.minToMax": "Виберіть від {min} до {max} моделей.",
   "multirun.agentSelector.placeholder": "Вибрати агента",
+  "multirun.fusion.title": "Запустити fusion",
+  "multirun.fusion.description": "Обʼєднайте вибрані результати multi-run в одну сильнішу відповідь.",
+  "multirun.fusion.provider.placeholder": "Провайдер",
+  "multirun.fusion.model.placeholder": "Модель",
+  "multirun.fusion.sources.label": "Джерела ({count})",
+  "multirun.fusion.actions.cancel": "Скасувати",
+  "multirun.fusion.actions.start": "Запустити fusion",
+  "multirun.fusion.actions.starting": "Запуск...",
+  "multirun.fusion.toast.noOutputs": "Не знайдено відповідей асистента для fusion.",
+  "multirun.fusion.toast.failed": "Не вдалося запустити fusion.",
   "sessions.sidebar.header.actions.searchSessions": "Пошук сесій",
   "sessions.sidebar.header.actions.exitSelection": "Вийти з вибору",
   "sessions.sidebar.header.actions.selectSessions": "Вибрати сесії",
@@ -243,6 +253,7 @@ export const dict: Record<I18nKey, string> = {
   "sessions.sidebar.session.menu.copyLink": "Копіювати посилання",
   "sessions.sidebar.session.menu.unshare": "Скасувати спільний доступ",
   "sessions.sidebar.session.menu.exportMarkdown": "Експорт Markdown",
+  "sessions.sidebar.session.menu.runFusion": "Запустити fusion",
   "sessions.sidebar.session.menu.openInSidePanel": "Відкрити на бічній панелі",
   "sessions.sidebar.session.menu.betaBadge": "бета-версія",
   "sessions.sidebar.session.menu.label": "Меню сесії",

packages/ui/src/lib/i18n/messages/zh-CN.settings.ts

@@ -164,6 +164,7 @@ export const settingsDict = {
   'settings.magicPrompts.sidebar.item.planImplement': '执行计划',
   'settings.magicPrompts.sidebar.item.sessionSummary': '会话总结',
   'settings.magicPrompts.sidebar.item.sessionWorkspaceReview': '工作区审查',
+  'settings.magicPrompts.sidebar.item.sessionFusion': 'Fusion',
   'settings.remoteInstances.sidebar.title': '远程实例',
   'settings.remoteInstances.sidebar.total': '总计 {count}',
   'settings.remoteInstances.sidebar.newSshInstanceName': '新建 SSH 实例',
@@ -1541,6 +1542,8 @@ export const settingsDict = {
   'settings.magicPrompts.page.group.sessionSummary.description': '由 /summary 斜杠命令使用的提示词：可见用户消息 + 隐藏说明。非破坏性，不会压缩会话历史。',
   'settings.magicPrompts.page.group.sessionWorkspaceReview.title': '工作区审查',
   'settings.magicPrompts.page.group.sessionWorkspaceReview.description': '由 /workspace-review 斜杠命令使用的提示词：可见用户消息 + 隐藏说明。仅审查当前工作区的高信号问题。',
+  'settings.magicPrompts.page.group.sessionFusion.title': 'Fusion',
+  'settings.magicPrompts.page.group.sessionFusion.description': '用于将 multi-run 输出合并为一个最终答案的提示词：可见用户消息 + 源结果前的隐藏说明。',
   'settings.magicPrompts.page.actions.resetting': '重置中...',
   'settings.magicPrompts.page.actions.resetAllOverrides': '重置全部覆盖',
   'settings.magicPrompts.page.actions.resetToDefault': '重置为默认',

packages/ui/src/lib/i18n/messages/zh-CN.ts

@@ -181,6 +181,16 @@ export const dict: Record<I18nKey, string> = {
   'multirun.modelMultiSelect.validation.minOnly': '请至少选择 {min} 个模型。',
   'multirun.modelMultiSelect.validation.minToMax': '请选择 {min} 到 {max} 个模型。',
   'multirun.agentSelector.placeholder': '选择智能体',
+  'multirun.fusion.title': '运行 fusion',
+  'multirun.fusion.description': '将选中的 multi-run 输出合并为一个更强的答案。',
+  'multirun.fusion.provider.placeholder': 'Provider',
+  'multirun.fusion.model.placeholder': 'Model',
+  'multirun.fusion.sources.label': '来源（{count}）',
+  'multirun.fusion.actions.cancel': '取消',
+  'multirun.fusion.actions.start': '开始 fusion',
+  'multirun.fusion.actions.starting': '正在开始...',
+  'multirun.fusion.toast.noOutputs': '未找到可用于 fusion 的助手输出。',
+  'multirun.fusion.toast.failed': '启动 fusion 失败。',
   'sessions.sidebar.header.actions.searchSessions': '搜索会话',
   'sessions.sidebar.header.actions.exitSelection': '退出选择',
   'sessions.sidebar.header.actions.selectSessions': '选择会话',
@@ -243,6 +253,7 @@ export const dict: Record<I18nKey, string> = {
   'sessions.sidebar.session.menu.copyLink': '复制链接',
   'sessions.sidebar.session.menu.unshare': '取消分享',
   'sessions.sidebar.session.menu.exportMarkdown': '导出 Markdown',
+  'sessions.sidebar.session.menu.runFusion': '运行 fusion',
   'sessions.sidebar.session.menu.openInSidePanel': '在侧边面板中打开',
   'sessions.sidebar.session.menu.betaBadge': 'beta',
   'sessions.sidebar.session.menu.label': '会话菜单',

packages/ui/src/lib/magicPrompts.ts

@@ -26,7 +26,9 @@ export type MagicPromptId =
   | 'session.summary.visible'
   | 'session.summary.instructions'
   | 'session.review.visible'
-  | 'session.review.instructions';
+  | 'session.review.instructions'
+  | 'session.fusion.visible'
+  | 'session.fusion.instructions';
 
 export interface MagicPromptDefinition {
   id: MagicPromptId;
@@ -570,6 +572,26 @@ Output:
 
 Keep the review concise and practical.`,
   },
+  {
+    id: 'session.fusion.visible',
+    title: 'Fusion Visible Prompt',
+    group: 'Session',
+    description: 'Visible user message for multi-run fusion sessions.',
+    template: 'Create the best combined answer from the multi-run results.',
+  },
+  {
+    id: 'session.fusion.instructions',
+    title: 'Fusion Instructions',
+    group: 'Session',
+    description: 'Hidden instructions used before multi-run source outputs in fusion sessions.',
+    template: `You are performing fusion over multiple model outputs from the same original task.
+
+Goal: produce the strongest possible final answer by combining complementary information, resolving conflicts, removing duplicates, and preserving useful nuance.
+
+Use the results below as source material. Do not mention that the inputs were hidden parts. If sources disagree, prefer the most specific, well-supported, and internally consistent answer.
+
+--- FUSION INPUTS START ---`,
+  },
 ] as const;
 
 const MAGIC_PROMPT_DEFINITION_BY_ID = new Map<MagicPromptId, MagicPromptDefinition>(

packages/ui/src/lib/multirun/title.ts

@@ -0,0 +1,42 @@
+export type ParsedMultiRunTitle = {
+  groupSlug: string;
+  providerID: string;
+  modelID: string;
+  index?: number;
+  fusion: boolean;
+};
+
+const GROUP_SLUG_PATTERN = /^[a-z0-9](?:[a-z0-9-]{0,48}[a-z0-9])?$/;
+
+export const parseMultiRunSessionTitle = (title?: string | null): ParsedMultiRunTitle | null => {
+  if (!title) return null;
+  const segments = title.split('/');
+  if (segments.length !== 3 && segments.length !== 4) return null;
+
+  const [groupSlug, providerID, modelID, suffix] = segments;
+  if (!GROUP_SLUG_PATTERN.test(groupSlug)) return null;
+  if (!providerID?.trim() || !modelID?.trim()) return null;
+  if (providerID !== providerID.trim() || modelID !== modelID.trim()) return null;
+
+  if (segments.length === 3) {
+    return { groupSlug, providerID, modelID, fusion: false };
+  }
+
+  if (suffix === 'fusion') {
+    return { groupSlug, providerID, modelID, fusion: true };
+  }
+
+  if (!/^\d+$/.test(suffix)) return null;
+  const index = Number.parseInt(suffix, 10);
+  if (!Number.isSafeInteger(index) || index <= 0) return null;
+
+  return { groupSlug, providerID, modelID, index, fusion: false };
+};
+
+export const isMultiRunSessionTitle = (title?: string | null): boolean => {
+  return parseMultiRunSessionTitle(title) !== null;
+};
+
+export const getFusionSessionTitle = (groupSlug: string, providerID: string, modelID: string): string => {
+  return `${groupSlug}/${providerID}/${modelID}/fusion`;
+};