feat(webui): add lightweight session messaging via mentions

2026-09-01 16:51:53 +03:00 · 2026-08-19 01:15:56 +08:00
parent 2bdb11eeba
commit 0e184965e8
76 changed files with 8297 additions and 658 deletions
@@ -2331,6 +2331,18 @@ function Shell({
      .map((key) => byKey.get(key))
      .filter((session): session is ChatSummary => session !== undefined);
  }, [activeTabKey, activeTabState, orderedWorkbenchTabsByKey, sessions]);
+  const collaborationSessions = useMemo(() => {
+    const nearby = workbenchPaneSessions.length > 0
+      ? workbenchPaneSessions
+      : activeSession
+        ? [activeSession]
+        : [];
+    const nearbyKeys = new Set(nearby.map((session) => session.key));
+    return [
+      ...nearby,
+      ...sessions.filter((session) => !nearbyKeys.has(session.key)),
+    ];
+  }, [activeSession, sessions, workbenchPaneSessions]);
  const paneChromeEnabled = Boolean(
    activeKey && activeSession && !temporaryChatActive && activeTabState,
  );
@@ -2379,6 +2391,7 @@ function Shell({
          key: session.key,
          chatId: session.chatId,
          title: titleForSession(session),
+          handle: session.handle,
        }));
      return [presentation.rowKey, {
        tabKey: orderedTab.tabKey,
@@ -2746,7 +2759,7 @@ function Shell({
                    return (
                      <ThreadShell
                        session={activeSession}
-                        sessions={sessions}
+                        sessions={collaborationSessions}
                        title={headerTitle}
                        temporary={temporaryChatRequested}
                        temporaryChatIds={temporaryChatIds}
@@ -2791,7 +2804,7 @@ function Shell({
                  return (
                    <ThreadShell
                      session={paneSession}
-                      sessions={sessions}
+                      sessions={collaborationSessions}
                      title={pane.title}
                      onToggleSidebar={toggleSidebar}
                      onNewChat={onNewChat}
@@ -50,6 +50,7 @@ import {
 } from "@/components/ui/tooltip";
 import { MAX_WORKBENCH_PANES } from "@/components/workbench/workbench-model";
 import { SIDEBAR_SELECTION_ITEM_CLASS } from "@/components/SidebarSelectionHighlight";
+import { SessionHandleHighlight, sessionHandleColor } from "@/components/CliAppMentionText";
 import { deriveTitle, relativeTime, visibleSessionPreview } from "@/lib/format";
 import {
  COLLAPSED_CHATS_VISIBLE_COUNT,
@@ -103,8 +104,10 @@ function SidebarItemTooltip({

 function SidebarSelectionTrack({
  active,
+  handle,
 }: {
  active: boolean;
+  handle: ChatSummary["handle"];
 }) {
  return (
    <span
@@ -112,14 +115,31 @@ function SidebarSelectionTrack({
      data-active={active ? "true" : "false"}
      aria-hidden
      className={cn(
-        "pointer-events-none absolute inset-x-0 bottom-0 h-0.5 origin-left rounded-full bg-current",
+        "pointer-events-none absolute inset-x-0 bottom-0 h-0.5 origin-left rounded-full",
        "transition-transform duration-200 ease-out motion-reduce:transition-none",
        active ? "scale-x-100" : "scale-x-0",
      )}
+      style={{
+        backgroundColor: handle ? sessionHandleColor(handle.color_slot) : "currentColor",
+      }}
    />
  );
 }

+function SidebarSessionHandle({ handle }: { handle: ChatSummary["handle"] }) {
+  if (!handle) return null;
+  return (
+    <span
+      data-sidebar-handle-handle
+      className="flex max-w-20 shrink-0 items-center overflow-hidden whitespace-nowrap text-[11px] font-medium leading-5"
+    >
+      <SessionHandleHighlight handle={handle}>
+        @{handle.name}
+      </SessionHandleHighlight>
+    </span>
+  );
+}
+
 function readCollapsedPaneGroups(): Set<string> {
  try {
    const value = JSON.parse(window.localStorage.getItem(
@@ -160,6 +180,7 @@ export interface SidebarPaneGroup {
    key: string;
    chatId: string;
    title: string;
+    handle?: ChatSummary["handle"];
  }>;
 }

@@ -965,27 +986,29 @@ export const ChatList = memo(function ChatList({
                                  partial={tabPartiallySelected}
                                />
                              ) : null}
-                              <span className="min-w-0 flex-1 overflow-hidden">
-                                {projectMode ? (
-                                  <span className="relative flex w-full min-w-0 items-baseline gap-2">
-                                    <span className="min-w-0 flex-1 truncate font-medium leading-5">
-                                      {title}
-                                    </span>
-                                    {isPinned ? <PinnedChatIndicator /> : null}
+                                <span className="min-w-0 flex-1 overflow-hidden">
+                                  {projectMode ? (
+                                    <span className="relative flex w-full min-w-0 items-baseline gap-2">
+                                      <SidebarSessionHandle handle={s.handle} />
+                                      <span className="min-w-0 flex-1 truncate font-medium leading-5">
+                                        {title}
+                                      </span>
+                                      {isPinned ? <PinnedChatIndicator /> : null}
                                    {timestamp ? (
                                      <span className="shrink-0 text-[11.5px] font-medium text-muted-foreground/58">
                                        {timestamp}
                                      </span>
                                    ) : null}
-                                    <SidebarSelectionTrack active={topicActive} />
+                                    <SidebarSelectionTrack active={topicActive} handle={s.handle} />
                                  </span>
                                ) : (
                                  <span className="relative flex w-full min-w-0 items-center gap-1.5">
+                                    <SidebarSessionHandle handle={s.handle} />
                                    <span className="min-w-0 flex-1 truncate font-medium leading-5">
                                      {title}
                                    </span>
                                    {isPinned ? <PinnedChatIndicator /> : null}
-                                    <SidebarSelectionTrack active={topicActive} />
+                                    <SidebarSelectionTrack active={topicActive} handle={s.handle} />
                                  </span>
                                )}
                                {showPreview ? (
@@ -1405,7 +1428,9 @@ function ActivePaneRows({
                  && "bg-sidebar-accent/55 text-sidebar-accent-foreground",
              )}
            >
-              <SidebarItemTooltip label={pane.title}>
+              <SidebarItemTooltip
+                label={pane.handle ? `@${pane.handle.name} · ${pane.title}` : pane.title}
+              >
                <button
                  type="button"
                  onClick={(event) => {
@@ -1437,9 +1462,10 @@ function ActivePaneRows({
                    <SelectionIndicator checked={selected} partial={false} />
                  ) : null}
                  <span className="relative flex min-w-0 flex-1 items-center gap-2 overflow-hidden">
+                    <SidebarSessionHandle handle={pane.handle} />
                    <span className="min-w-0 flex-1 truncate">{pane.title}</span>
                    {isPinned ? <PinnedChatIndicator /> : null}
-                    <SidebarSelectionTrack active={active} />
+                    <SidebarSelectionTrack active={active} handle={pane.handle} />
                  </span>
                </button>
              </SidebarItemTooltip>
@@ -1,4 +1,4 @@
-import { useMemo } from "react";
+import { useMemo, type ReactNode } from "react";
 import { useTranslation } from "react-i18next";

 import {
@@ -7,7 +7,12 @@ import {
 } from "@/components/InlineTokenHighlight";
 import { useLogoFallback } from "@/hooks/useLogoFallback";
 import { logoFallbackUrls } from "@/lib/provider-brand";
-import type { CliAppInfo, McpPresetInfo, SessionMention } from "@/lib/types";
+import type {
+  CliAppInfo,
+  McpPresetInfo,
+  SessionHandle,
+  SessionMention,
+} from "@/lib/types";
 import { cn } from "@/lib/utils";

 type CliAppMentionSegment =
@@ -17,8 +22,56 @@ type CliAppMentionSegment =
 export type CapabilityMentionSegment =
  | CliAppMentionSegment
  | { kind: "mcp"; text: string; preset: McpPresetInfo }
+  | { kind: "handle"; text: string; handle: SessionHandle };
+
+export type SessionReferenceSegment =
+  | { kind: "text"; text: string }
  | { kind: "session"; text: string; mention: SessionMention };

+export interface TokenSelection<T> {
+  mention: T;
+  start: number;
+  end: number;
+}
+
+export type SessionHandleSelection = TokenSelection<SessionHandle>;
+export type SessionMentionSelection = TokenSelection<SessionMention>;
+
+const SESSION_HANDLE_COLOR_COUNT = 8;
+
+export function sessionHandleColor(colorSlot: number): string {
+  const slot = Number.isFinite(colorSlot)
+    ? Math.abs(Math.trunc(colorSlot)) % SESSION_HANDLE_COLOR_COUNT
+    : 0;
+  return `var(--session-handle-${slot})`;
+}
+
+export function SessionHandleHighlight({
+  handle,
+  children,
+  className,
+  testId,
+}: {
+  handle: Pick<SessionHandle, "color_slot" | "name">;
+  children: ReactNode;
+  className?: string;
+  testId?: string;
+}) {
+  return (
+    <span
+      className="inline border-b-2"
+      style={{ borderBottomColor: sessionHandleColor(handle.color_slot) }}
+    >
+      <InlineTokenHighlight
+        testId={testId}
+        className={cn("text-foreground", className)}
+      >
+        {children}
+      </InlineTokenHighlight>
+    </span>
+  );
+}
+
 export function cliAppInitials(app: CliAppInfo): string {
  const value = app.display_name || app.name;
  return (
@@ -30,6 +83,7 @@ export function cliAppInitials(app: CliAppInfo): string {
      .join("") || app.name.slice(0, 2).toUpperCase()
  );
 }
+
 export function mcpPresetInitials(preset: Pick<McpPresetInfo, "name" | "display_name">): string {
  const value = preset.display_name || preset.name;
  return (
@@ -41,13 +95,15 @@ export function mcpPresetInitials(preset: Pick<McpPresetInfo, "name" | "display_
      .join("") || preset.name.slice(0, 2).toUpperCase()
  );
 }
+
 export function splitCapabilityMentionSegments(
  value: string,
  cliApps: CliAppInfo[],
  mcpPresets: McpPresetInfo[] = [],
-  sessionMentions: SessionMention[] = [],
+  sessionHandles: SessionHandle[] = [],
+  handleSelections?: SessionHandleSelection[],
 ): CapabilityMentionSegment[] {
-  if (!value || (cliApps.length === 0 && mcpPresets.length === 0 && sessionMentions.length === 0)) {
+  if (!value || (cliApps.length === 0 && mcpPresets.length === 0 && sessionHandles.length === 0)) {
    return value ? [{ kind: "text", text: value }] : [];
  }
  const cliAppsByName = new Map(
@@ -60,10 +116,13 @@ export function splitCapabilityMentionSegments(
      .filter((preset) => preset.installed && preset.configured)
      .map((preset) => [preset.name.toLowerCase(), preset]),
  );
-  const sessionsByName = new Map(
-    sessionMentions.map((mention) => [mention.name.toLowerCase(), mention]),
+  const handlesByName = new Map(
+    sessionHandles.map((handle) => [handle.name.toLowerCase(), handle]),
  );
-  if (cliAppsByName.size === 0 && mcpPresetsByName.size === 0 && sessionsByName.size === 0) {
+  const selectedSessionNames = new Set(
+    (handleSelections ?? []).map((selection) => selection.mention.name.toLowerCase()),
+  );
+  if (cliAppsByName.size === 0 && mcpPresetsByName.size === 0 && handlesByName.size === 0) {
    return [{ kind: "text", text: value }];
  }

@@ -75,13 +134,15 @@ export function splitCapabilityMentionSegments(
    const prefix = match[1] ?? "";
    const name = match[2] ?? "";
    const key = name.toLowerCase();
-    const app = cliAppsByName.get(key);
-    const preset = app ? null : mcpPresetsByName.get(key);
-    const session = app || preset ? null : sessionsByName.get(key);
-    if (!app && !preset && !session) continue;
-
    const mentionStart = match.index + prefix.length;
    const mentionEnd = mentionStart + name.length + 1;
+    const handle = handleSelections
+      ? selectedSessionNames.has(key) ? handlesByName.get(key) : undefined
+      : handlesByName.get(key);
+    const app = handle ? null : cliAppsByName.get(key);
+    const preset = handle || app ? null : mcpPresetsByName.get(key);
+    if (!app && !preset && !handle) continue;
+
    if (mentionStart > cursor) {
      segments.push({ kind: "text", text: value.slice(cursor, mentionStart) });
    }
@@ -89,18 +150,51 @@ export function splitCapabilityMentionSegments(
      segments.push({ kind: "cli", text: value.slice(mentionStart, mentionEnd), app });
    } else if (preset) {
      segments.push({ kind: "mcp", text: value.slice(mentionStart, mentionEnd), preset });
-    } else if (session) {
-      segments.push({
-        kind: "session",
-        text: value.slice(mentionStart, mentionEnd),
-        mention: session,
-      });
+    } else if (handle) {
+      segments.push({ kind: "handle", text: value.slice(mentionStart, mentionEnd), handle });
    }
    cursor = mentionEnd;
  }
-  if (cursor < value.length) {
-    segments.push({ kind: "text", text: value.slice(cursor) });
+  if (cursor < value.length) segments.push({ kind: "text", text: value.slice(cursor) });
+  return segments.length ? segments : [{ kind: "text", text: value }];
+}
+
+export function splitSessionReferenceSegments(
+  value: string,
+  sessionMentions: SessionMention[] = [],
+  sessionSelections?: SessionMentionSelection[],
+  allowLegacyAt = false,
+): SessionReferenceSegment[] {
+  if (!value || sessionMentions.length === 0) return value ? [{ kind: "text", text: value }] : [];
+  const sessionsByName = new Map(
+    sessionMentions.map((mention) => [mention.name.toLowerCase(), mention]),
+  );
+  const selectedSessionByStart = new Map(
+    (sessionSelections ?? []).map((selection) => [selection.start, selection]),
+  );
+  const segments: SessionReferenceSegment[] = [];
+  const referenceRe = allowLegacyAt
+    ? /(^|[\s([{])([#@])([\p{L}\p{N}_-]+)(?=$|[^\p{L}\p{N}_-])/giu
+    : /(^|[\s([{])(#)([\p{L}\p{N}_-]+)(?=$|[^\p{L}\p{N}_-])/giu;
+  let cursor = 0;
+  let match: RegExpExecArray | null;
+  while ((match = referenceRe.exec(value)) !== null) {
+    const prefix = match[1] ?? "";
+    const name = match[3] ?? "";
+    const start = match.index + prefix.length;
+    const end = start + name.length + 1;
+    const selected = selectedSessionByStart.get(start);
+    const mention = sessionSelections
+      ? selected?.end === end && selected.mention.name.toLowerCase() === name.toLowerCase()
+        ? selected.mention
+        : undefined
+      : sessionsByName.get(name.toLowerCase());
+    if (!mention) continue;
+    if (start > cursor) segments.push({ kind: "text", text: value.slice(cursor, start) });
+    segments.push({ kind: "session", text: value.slice(start, end), mention });
+    cursor = end;
  }
+  if (cursor < value.length) segments.push({ kind: "text", text: value.slice(cursor) });
  return segments.length ? segments : [{ kind: "text", text: value }];
 }

@@ -133,10 +227,42 @@ export function CapabilityMentionToken({
      />
    );
  }
-  return <SessionMentionToken mention={segment.mention} label={segment.text} variant={variant} />;
+  return <SessionHandleToken handle={segment.handle} label={segment.text} variant={variant} />;
 }

-export function SessionMentionToken({
+export function SessionHandleToken({
+  handle,
+  label,
+  variant,
+}: {
+  handle: SessionHandle;
+  label: string;
+  variant: "composer" | "message";
+}) {
+  const testIdPrefix = variant === "composer" ? "composer" : "message";
+  const color = sessionHandleColor(handle.color_slot);
+  const token = (
+    <SessionHandleHighlight
+      handle={handle}
+      testId={`${testIdPrefix}-handle-mention-${handle.name}`}
+      className={variant === "composer" ? "font-normal" : undefined}
+    >
+      {label}
+    </SessionHandleHighlight>
+  );
+  if (variant === "composer" || !handle.session_key) return token;
+  return (
+    <a
+      href={`#/chat/${encodeURIComponent(handle.session_key)}`}
+      className="rounded-sm underline-offset-2 hover:underline focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring/60"
+      style={{ textDecorationColor: color }}
+    >
+      {token}
+    </a>
+  );
+}
+
+export function SessionReferenceToken({
  mention,
  label,
  variant,
@@ -148,7 +274,7 @@ export function SessionMentionToken({
  const testIdPrefix = variant === "composer" ? "composer" : "message";
  const token = (
    <InlineTokenHighlight
-      testId={`${testIdPrefix}-session-mention-${mention.name}`}
+      testId={`${testIdPrefix}-session-reference-${mention.name}`}
      title={`Session: ${mention.title || mention.name}`}
      color={INLINE_TOKEN_HIGHLIGHT_COLOR}
      className={variant === "composer" ? "font-normal" : undefined}
@@ -13,7 +13,7 @@ export function InlineTokenHighlight({
 }: {
  children: ReactNode;
  className?: string;
-  color: string;
+  color?: string;
  testId?: string;
  title?: string;
 }) {
@@ -25,7 +25,7 @@ export function InlineTokenHighlight({
        "relative inline font-[550] transition-colors duration-150",
        className,
      )}
-      style={{ color }}
+      style={color ? { color } : undefined}
    >
      {children}
    </span>
@@ -8,6 +8,7 @@ import {
 } from "react";

 import { cn } from "@/lib/utils";
+import type { SessionHandle } from "@/lib/types";

 interface MarkdownTextProps {
  children: string;
@@ -15,6 +16,7 @@ interface MarkdownTextProps {
  streaming?: boolean;
  preserveStreamingLayout?: boolean;
  onOpenFilePreview?: (path: string) => void;
+  sessionHandles?: SessionHandle[];
 }

 const loadMarkdownRenderer = () => import("@/components/MarkdownTextRenderer");
@@ -26,12 +28,14 @@ const MemoizedMarkdownRenderer = memo(function MemoizedMarkdownRenderer({
  highlightCode,
  streaming,
  onOpenFilePreview,
+  sessionHandles,
 }: {
  source: string;
  className?: string;
  highlightCode: boolean;
  streaming: boolean;
  onOpenFilePreview?: (path: string) => void;
+  sessionHandles?: SessionHandle[];
 }) {
  return (
    <LazyMarkdownRenderer
@@ -39,6 +43,7 @@ const MemoizedMarkdownRenderer = memo(function MemoizedMarkdownRenderer({
      highlightCode={highlightCode}
      streaming={streaming}
      onOpenFilePreview={onOpenFilePreview}
+      sessionHandles={sessionHandles}
    >
      {source}
    </LazyMarkdownRenderer>
@@ -77,6 +82,7 @@ export function MarkdownText({
  streaming = false,
  preserveStreamingLayout = false,
  onOpenFilePreview,
+  sessionHandles,
 }: MarkdownTextProps) {
  const renderedSource = children;
  const renderPhase = streaming ? "streaming" : "complete";
@@ -108,6 +114,7 @@ export function MarkdownText({
          highlightCode={highlightCode}
          streaming={renderWithStreamingLayout}
          onOpenFilePreview={onOpenFilePreview}
+          sessionHandles={sessionHandles}
        />
      </Suspense>
    </MarkdownRendererBoundary>
@@ -16,6 +16,7 @@ import { Streamdown, type Components, type StreamdownProps } from "streamdown";

 import { AttachmentTile } from "@/components/AttachmentTile";
 import { CodeBlock } from "@/components/CodeBlock";
+import { SessionHandleHighlight, sessionHandleColor } from "@/components/CliAppMentionText";
 import {
  INLINE_TOKEN_HIGHLIGHT_COLOR,
  InlineTokenHighlight,
@@ -34,6 +35,7 @@ import { inferMediaKind } from "@/lib/media";
 import { browserSafeFaviconUrls } from "@/lib/provider-brand";
 import { remarkTexMath } from "@/lib/remark-tex-math";
 import { cn } from "@/lib/utils";
+import type { SessionHandle } from "@/lib/types";

 import "katex/dist/katex.min.css";
 import "streamdown/styles.css";
@@ -44,11 +46,13 @@ interface MarkdownTextRendererProps {
  highlightCode?: boolean;
  streaming?: boolean;
  onOpenFilePreview?: (path: string) => void;
+  sessionHandles?: SessionHandle[];
 }

 type MarkdownAstNode = {
  type: string;
  value?: string;
+  url?: string;
  children?: MarkdownAstNode[];
  data?: {
    hName?: string;
@@ -277,7 +281,108 @@ function remarkCjkStrongBoundaries() {
  };
 }

-const remarkPlugins: NonNullable<StreamdownProps["remarkPlugins"]> = [
+const SESSION_HANDLE_PATTERN = /@([\p{L}\p{N}_-]+)/gu;
+const SESSION_HANDLE_SKIP_NODES = new Set([
+  "code",
+  "html",
+  "inlineCode",
+  "inlineMath",
+  "link",
+  "linkReference",
+  "math",
+]);
+const VOID_HTML_TAGS = new Set([
+  "area",
+  "base",
+  "br",
+  "col",
+  "embed",
+  "hr",
+  "img",
+  "input",
+  "link",
+  "meta",
+  "param",
+  "source",
+  "track",
+  "wbr",
+]);
+const RAW_HTML_TAG_PATTERN = /<\s*(\/?)\s*([a-z][\w:-]*)(?:\s[^<>]*?)?(\/?)\s*>/giu;
+
+function normalizeSessionHandle(value: string): string {
+  return value.normalize("NFKC").toLocaleLowerCase();
+}
+
+function sessionHandleNodes(
+  value: string,
+  handlesByName: ReadonlyMap<string, SessionHandle>,
+): MarkdownAstNode[] | null {
+  const replacement: MarkdownAstNode[] = [];
+  let cursor = 0;
+  for (const match of value.matchAll(SESSION_HANDLE_PATTERN)) {
+    const start = match.index;
+    const previous = start > 0 ? value[start - 1] : "";
+    if (previous && /[\p{L}\p{N}_@-]/u.test(previous)) continue;
+    const handle = handlesByName.get(normalizeSessionHandle(match[1]));
+    if (!handle) continue;
+    if (start > cursor) replacement.push(safeText(value.slice(cursor, start)));
+    replacement.push({
+      type: "link",
+      url: `#session-handle/${encodeURIComponent(handle.session_key)}`,
+      children: [safeText(match[0])],
+    });
+    cursor = start + match[0].length;
+  }
+  if (cursor === 0) return null;
+  if (cursor < value.length) replacement.push(safeText(value.slice(cursor)));
+  return replacement;
+}
+
+function rawHtmlNestingDelta(value: string | undefined): number {
+  if (!value) return 0;
+  let delta = 0;
+  for (const match of value.matchAll(RAW_HTML_TAG_PATTERN)) {
+    const closing = match[1] === "/";
+    const tagName = match[2].toLowerCase();
+    const selfClosing = match[3] === "/" || VOID_HTML_TAGS.has(tagName);
+    if (closing) delta -= 1;
+    else if (!selfClosing) delta += 1;
+  }
+  return delta;
+}
+
+function transformKnownSessionHandles(
+  node: MarkdownAstNode,
+  handlesByName: ReadonlyMap<string, SessionHandle>,
+): void {
+  if (
+    !node.children
+    || SESSION_HANDLE_SKIP_NODES.has(node.type)
+    || node.type.startsWith("nanobotSafeHtml")
+  ) return;
+  let rawHtmlDepth = 0;
+  node.children = node.children.flatMap((child) => {
+    if (child.type === "html") {
+      rawHtmlDepth = Math.max(0, rawHtmlDepth + rawHtmlNestingDelta(child.value));
+      return [child];
+    }
+    if (rawHtmlDepth > 0) return [child];
+    if (child.type !== "text" || !child.value?.includes("@")) {
+      transformKnownSessionHandles(child, handlesByName);
+      return [child];
+    }
+    return sessionHandleNodes(child.value, handlesByName) ?? [child];
+  });
+}
+
+function remarkKnownSessionHandles({ handles }: { handles: SessionHandle[] }) {
+  const handlesByName = new Map(
+    handles.map((handle) => [normalizeSessionHandle(handle.name), handle]),
+  );
+  return (tree: MarkdownAstNode) => transformKnownSessionHandles(tree, handlesByName);
+}
+
+const baseRemarkPlugins: NonNullable<StreamdownProps["remarkPlugins"]> = [
  remarkBreaks,
  remarkGfm,
  [remarkMath, { singleDollarTextMath: false }],
@@ -517,8 +622,22 @@ export default function MarkdownTextRenderer({
  highlightCode = true,
  streaming = false,
  onOpenFilePreview,
+  sessionHandles = [],
 }: MarkdownTextRendererProps) {
  const { t } = useTranslation();
+  const handlesBySessionKey = useMemo(
+    () => new Map(sessionHandles.map((handle) => [handle.session_key, handle])),
+    [sessionHandles],
+  );
+  const remarkPlugins = useMemo(
+    () => sessionHandles.length > 0
+      ? [
+          ...baseRemarkPlugins,
+          [remarkKnownSessionHandles, { handles: sessionHandles }],
+        ] as NonNullable<StreamdownProps["remarkPlugins"]>
+      : baseRemarkPlugins,
+    [sessionHandles],
+  );
  const components = useMemo<Components>(
    () => ({
      code({ className: cls, children: kids, node: _node, ...props }) {
@@ -612,6 +731,30 @@ export default function MarkdownTextRenderer({
        if (href === "streamdown:incomplete-link") {
          return <>{markdownChildren}</>;
        }
+        if (href.startsWith("#session-handle/")) {
+          let handle: SessionHandle | undefined;
+          try {
+            handle = handlesBySessionKey.get(decodeURIComponent(href.slice("#session-handle/".length)));
+          } catch {
+            handle = undefined;
+          }
+          if (!handle) return <>{markdownChildren}</>;
+          const color = sessionHandleColor(handle.color_slot);
+          return (
+            <a
+              href={`#/chat/${encodeURIComponent(handle.session_key)}`}
+              className="rounded-sm no-underline focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring/60"
+              style={{ textDecorationColor: color }}
+            >
+              <SessionHandleHighlight
+                handle={handle}
+                testId={`message-handle-mention-${handle.name}`}
+              >
+                {markdownChildren}
+              </SessionHandleHighlight>
+            </a>
+          );
+        }
        const sessionHref = sessionReferenceHref(href);
        if (sessionHref) {
          return (
@@ -790,7 +933,7 @@ export default function MarkdownTextRenderer({
        );
      },
    }),
-    [highlightCode, onOpenFilePreview, t],
+    [highlightCode, onOpenFilePreview, handlesBySessionKey, t],
  );

  return (
@@ -20,6 +20,7 @@ import {
 import { useTranslation } from "react-i18next";

 import { AttachmentTile } from "@/components/AttachmentTile";
+import { sessionHandleColor } from "@/components/CliAppMentionText";
 import { ImageLightbox } from "@/components/ImageLightbox";
 import { MarkdownText } from "@/components/MarkdownText";
 import { SlashCommandText } from "@/components/SlashCommandText";
@@ -48,6 +49,7 @@ import type {
  UIMessage,
  MessageDeliveryErrorKind,
  MessageDeliveryStatus,
+  SessionHandle,
 } from "@/lib/types";

 interface MessageBubbleProps {
@@ -61,6 +63,7 @@ interface MessageBubbleProps {
  cliApps?: CliAppInfo[];
  mcpPresets?: McpPresetInfo[];
  slashCommands?: SlashCommand[];
+  sessionDirectory?: SessionHandle[];
  onOpenFilePreview?: (path: string) => void;
  onForkFromHere?: () => void;
 }
@@ -259,6 +262,77 @@ function UserDeliveryStatus({
  );
 }

+function IncomingSessionMessage({
+  message,
+  showCopyAction,
+  sessionDirectory,
+  onOpenFilePreview,
+}: {
+  message: UIMessage;
+  showCopyAction: boolean;
+  sessionDirectory: SessionHandle[];
+  onOpenFilePreview?: (path: string) => void;
+}) {
+  const handle = message.sessionMessage!.session;
+  const activeSession = sessionDirectory.find((candidate) => candidate.id === handle.id);
+  const color = sessionHandleColor(handle.color_slot);
+  const createdAtLabel = formatMessageEndTime(message.createdAt);
+  const handleName = `@${handle.name}`;
+  const name = <span className="font-medium text-foreground">{handleName}</span>;
+
+  return (
+    <div
+      data-handle-message="incoming"
+      className="group w-full text-[15px]"
+      style={{ lineHeight: "var(--cjk-line-height)" }}
+    >
+      <div
+        data-handle-message-body
+        className="min-w-0 rounded-es-[16px] border-s-2 bg-background pb-1 ps-2.5"
+        style={{ borderInlineStartColor: color }}
+      >
+        <div className="mb-1.5 flex items-center text-[12px] text-muted-foreground">
+          {activeSession?.session_key ? (
+            <a
+              href={`#/chat/${encodeURIComponent(activeSession.session_key)}`}
+              className="rounded-sm underline-offset-2 hover:underline focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring/60"
+            >
+              {name}
+            </a>
+          ) : name}
+        </div>
+        <div data-assistant-selectable="true" className="min-w-0">
+          <MarkdownText
+            preserveStreamingLayout
+            onOpenFilePreview={onOpenFilePreview}
+            sessionHandles={sessionDirectory}
+          >
+            {message.content}
+          </MarkdownText>
+        </div>
+      </div>
+      {createdAtLabel || showCopyAction ? (
+        <TooltipProvider delayDuration={220} skipDelayDuration={80}>
+          <div
+            data-handle-footer
+            className="mt-1 flex min-h-8 items-center gap-1.5 text-muted-foreground"
+          >
+            {showCopyAction ? <MessageCopyButton content={message.content} /> : null}
+            {createdAtLabel ? (
+              <MessageTimestamp
+                timestamp={message.createdAt}
+                tooltipLabel={fmtDateTime(message.createdAt)}
+              >
+                {createdAtLabel}
+              </MessageTimestamp>
+            ) : null}
+          </div>
+        </TooltipProvider>
+      ) : null}
+    </div>
+  );
+}
+
 /** Render user turns as compact bubbles and assistant turns as document-like prose. */
 export function MessageBubble({
  message,
@@ -268,6 +342,7 @@ export function MessageBubble({
  cliApps = [],
  mcpPresets = [],
  slashCommands = [],
+  sessionDirectory = [],
  onOpenFilePreview,
  onForkFromHere,
 }: MessageBubbleProps) {
@@ -285,6 +360,17 @@ export function MessageBubble({
    return <TraceGroup message={message} />;
  }

+  if (message.role === "user" && message.sessionMessage?.direction === "incoming") {
+    return (
+      <IncomingSessionMessage
+        message={message}
+        showCopyAction={showCopyAction}
+        sessionDirectory={sessionDirectory}
+        onOpenFilePreview={onOpenFilePreview}
+      />
+    );
+  }
+
  if (message.role === "user") {
    const images = message.images ?? [];
    const media = message.media ?? [];
@@ -308,6 +394,9 @@ export function MessageBubble({
          cliApps={mentionCliApps}
          mcpPresets={mentionMcpPresets}
          sessionMentions={message.sessionMentions}
+          sessionHandles={message.sessionHandles}
+          attachedCliApps={message.cliApps}
+          attachedMcpPresets={message.mcpPresets}
        />
      </>
    ) : (
@@ -316,6 +405,9 @@ export function MessageBubble({
        cliApps={mentionCliApps}
        mcpPresets={mentionMcpPresets}
        sessionMentions={message.sessionMentions}
+        sessionHandles={message.sessionHandles}
+        attachedCliApps={message.cliApps}
+        attachedMcpPresets={message.mcpPresets}
      />
    );
    return (
@@ -433,6 +525,7 @@ export function MessageBubble({
              streaming={!!message.isStreaming}
              preserveStreamingLayout
              onOpenFilePreview={onOpenFilePreview}
+              sessionHandles={sessionDirectory}
            >
              {message.content}
            </MarkdownText>
@@ -3,14 +3,24 @@ import { useTranslation } from "react-i18next";

 import {
  CapabilityMentionToken,
+  SessionReferenceToken,
  splitCapabilityMentionSegments,
+  splitSessionReferenceSegments,
  type CapabilityMentionSegment,
+  type SessionReferenceSegment,
 } from "@/components/CliAppMentionText";
 import {
  INLINE_TOKEN_HIGHLIGHT_COLOR,
  InlineTokenHighlight,
 } from "@/components/InlineTokenHighlight";
-import type { CliAppInfo, McpPresetInfo, SessionMention } from "@/lib/types";
+import type {
+  CliAppInfo,
+  McpPresetInfo,
+  SessionHandle,
+  SessionMention,
+  UICliAppAttachment,
+  UIMcpPresetAttachment,
+} from "@/lib/types";

 type SkillReferenceSegment =
  | { kind: "text"; text: string }
@@ -18,6 +28,7 @@ type SkillReferenceSegment =

 type UserMessageSegment =
  | CapabilityMentionSegment
+  | SessionReferenceSegment
  | { kind: "skill"; text: string; name: string };

 function splitSkillReferenceSegments(value: string): SkillReferenceSegment[] {
@@ -49,18 +60,75 @@ function splitUserMessageSegments(
  cliApps: CliAppInfo[],
  mcpPresets: McpPresetInfo[],
  sessionMentions: SessionMention[],
+  sessionHandles: SessionHandle[],
+  attachedCliApps: UICliAppAttachment[],
+  attachedMcpPresets: UIMcpPresetAttachment[],
 ): UserMessageSegment[] {
  const segments: UserMessageSegment[] = [];
-  for (const segment of splitCapabilityMentionSegments(
-    value,
-    cliApps,
-    mcpPresets,
-    sessionMentions,
-  )) {
-    if (segment.kind === "text") {
-      segments.push(...splitSkillReferenceSegments(segment.text));
-    } else {
-      segments.push(segment);
+  const structuredAtNamespaces = new Map<string, "handle" | "cli" | "mcp">();
+  sessionHandles.forEach((handle) => {
+    structuredAtNamespaces.set(handle.name.toLowerCase(), "handle");
+  });
+  attachedCliApps.forEach((app) => {
+    const name = app.name.toLowerCase();
+    if (!structuredAtNamespaces.has(name)) structuredAtNamespaces.set(name, "cli");
+  });
+  attachedMcpPresets.forEach((preset) => {
+    const name = preset.name.toLowerCase();
+    if (!structuredAtNamespaces.has(name)) structuredAtNamespaces.set(name, "mcp");
+  });
+  const structuredAtNames = new Set(structuredAtNamespaces.keys());
+  const replayCliApps = cliApps.filter((app) => {
+    const owner = structuredAtNamespaces.get(app.name.toLowerCase());
+    return owner === undefined || owner === "cli";
+  });
+  const replayMcpPresets = mcpPresets.filter((preset) => {
+    const owner = structuredAtNamespaces.get(preset.name.toLowerCase());
+    return owner === undefined || owner === "mcp";
+  });
+  const replaySessionHandles = sessionHandles.filter((handle) => (
+    structuredAtNamespaces.get(handle.name.toLowerCase()) === "handle"
+  ));
+  const hashSegments = splitSessionReferenceSegments(value, sessionMentions);
+  const hashSessionKeys = new Set(hashSegments.flatMap((segment) => (
+    segment.kind === "session" ? [segment.mention.session_key] : []
+  )));
+  const legacySessionMentions = sessionMentions.filter((mention) => (
+    !hashSessionKeys.has(mention.session_key)
+    && !structuredAtNames.has(mention.name.toLowerCase())
+  ));
+
+  const appendCapabilitiesAndSkills = (text: string) => {
+    for (const capability of splitCapabilityMentionSegments(
+      text,
+      replayCliApps,
+      replayMcpPresets,
+      replaySessionHandles,
+    )) {
+      if (capability.kind === "text") {
+        segments.push(...splitSkillReferenceSegments(capability.text));
+      } else {
+        segments.push(capability);
+      }
+    }
+  };
+
+  for (const hashSegment of hashSegments) {
+    if (hashSegment.kind === "session") {
+      segments.push(hashSegment);
+      continue;
+    }
+    for (const legacySegment of splitSessionReferenceSegments(
+      hashSegment.text,
+      legacySessionMentions,
+      undefined,
+      true,
+    )) {
+      if (legacySegment.kind === "session") {
+        segments.push(legacySegment);
+      } else {
+        appendCapabilitiesAndSkills(legacySegment.text);
+      }
    }
  }
  return segments;
@@ -71,14 +139,28 @@ export function UserMessageText({
  cliApps,
  mcpPresets,
  sessionMentions = [],
+  sessionHandles = [],
+  attachedCliApps = [],
+  attachedMcpPresets = [],
 }: {
  text: string;
  cliApps: CliAppInfo[];
  mcpPresets: McpPresetInfo[];
  sessionMentions?: SessionMention[];
+  sessionHandles?: SessionHandle[];
+  attachedCliApps?: UICliAppAttachment[];
+  attachedMcpPresets?: UIMcpPresetAttachment[];
 }) {
  const { t } = useTranslation();
-  const segments = splitUserMessageSegments(text, cliApps, mcpPresets, sessionMentions);
+  const segments = splitUserMessageSegments(
+    text,
+    cliApps,
+    mcpPresets,
+    sessionMentions,
+    sessionHandles,
+    attachedCliApps,
+    attachedMcpPresets,
+  );
  return (
    <>
      {segments.map((segment, index) => {
@@ -95,6 +177,14 @@ export function UserMessageText({
            {segment.name}
          </InlineTokenHighlight>
        );
+        if (segment.kind === "session") return (
+          <SessionReferenceToken
+            key={`session-${segment.mention.session_key}-${index}`}
+            mention={segment.mention}
+            label={segment.text}
+            variant="message"
+          />
+        );
        return (
          <CapabilityMentionToken
            key={`${segment.kind}-${index}`}
@@ -3,6 +3,7 @@ import { type ReactNode } from "react";
 import { useTranslation } from "react-i18next";

 import { Button } from "@/components/ui/button";
+import { SessionHandleHighlight } from "@/components/CliAppMentionText";
 import {
  Tooltip,
  TooltipContent,
@@ -10,9 +11,11 @@ import {
  TooltipTrigger,
 } from "@/components/ui/tooltip";
 import { cn } from "@/lib/utils";
+import type { SessionHandle } from "@/lib/types";

 interface ThreadHeaderProps {
  title: string;
+  handle?: SessionHandle | null;
  onToggleSidebar: () => void;
  theme: "light" | "dark";
  onToggleTheme: () => void;
@@ -32,6 +35,7 @@ interface ThreadHeaderProps {

 export function ThreadHeader({
  title,
+  handle = null,
  onToggleSidebar,
  theme,
  onToggleTheme,
@@ -79,6 +83,16 @@ export function ThreadHeader({
            <span className="max-w-[min(60vw,32rem)] truncate">{title}</span>
          </div>
        ) : null}
+        {handle ? (
+          <span
+            data-testid="thread-handle-handle"
+            className="flex shrink-0 items-center rounded-md px-1.5 py-1 text-[12px] font-medium"
+          >
+            <SessionHandleHighlight handle={handle}>
+              @{handle.name}
+            </SessionHandleHighlight>
+          </span>
+        ) : null}
      </div>

      <div className="ml-auto flex shrink-0 items-center gap-1">
@@ -4,7 +4,13 @@ import { MessageBubble } from "@/components/MessageBubble";
 import { AgentActivityCluster } from "@/components/thread/AgentActivityCluster";
 import { AssistantSelectionAction } from "@/components/thread/AssistantSelectionAction";
 import { normalizeActivityTimeline, type TurnUnit } from "@/lib/activity-timeline";
-import type { CliAppInfo, McpPresetInfo, SlashCommand, UIMessage } from "@/lib/types";
+import type {
+  CliAppInfo,
+  McpPresetInfo,
+  SessionHandle,
+  SlashCommand,
+  UIMessage,
+} from "@/lib/types";

 interface ThreadMessagesProps {
  messages: UIMessage[];
@@ -18,6 +24,7 @@ interface ThreadMessagesProps {
  cliApps?: CliAppInfo[];
  mcpPresets?: McpPresetInfo[];
  slashCommands?: SlashCommand[];
+  sessionDirectory?: SessionHandle[];
  forkBoundaryMessageCount?: number | null;
  onOpenFilePreview?: (path: string) => void;
  onForkFromMessage?: (beforeUserIndex: number) => void;
@@ -62,6 +69,7 @@ export function ThreadMessages({
  cliApps = [],
  mcpPresets = [],
  slashCommands = [],
+  sessionDirectory = [],
  forkBoundaryMessageCount = null,
  onOpenFilePreview,
  onForkFromMessage,
@@ -159,6 +167,7 @@ export function ThreadMessages({
            cliApps={cliApps}
            mcpPresets={mcpPresets}
            slashCommands={slashCommands}
+            sessionDirectory={sessionDirectory}
            onOpenFilePreview={onOpenFilePreview}
            onForkFromMessage={onForkFromMessage}
          />
@@ -240,6 +249,7 @@ interface ThreadDisplayUnitProps {
  cliApps: CliAppInfo[];
  mcpPresets: McpPresetInfo[];
  slashCommands: SlashCommand[];
+  sessionDirectory: SessionHandle[];
  onOpenFilePreview?: (path: string) => void;
  onForkFromMessage?: (beforeUserIndex: number) => void;
 }
@@ -258,6 +268,7 @@ const ThreadDisplayUnit = memo(function ThreadDisplayUnit({
  cliApps,
  mcpPresets,
  slashCommands,
+  sessionDirectory,
  onOpenFilePreview,
  onForkFromMessage,
 }: ThreadDisplayUnitProps) {
@@ -296,6 +307,7 @@ const ThreadDisplayUnit = memo(function ThreadDisplayUnit({
            cliApps={cliApps}
            mcpPresets={mcpPresets}
            slashCommands={slashCommands}
+            sessionDirectory={sessionDirectory}
            onOpenFilePreview={onOpenFilePreview}
            onForkFromHere={forkIndex !== undefined ? onForkFromHere : undefined}
          />
@@ -324,6 +336,7 @@ function threadDisplayUnitPropsEqual(
    && previous.cliApps === next.cliApps
    && previous.mcpPresets === next.mcpPresets
    && previous.slashCommands === next.slashCommands
+    && previous.sessionDirectory === next.sessionDirectory
    && previous.onOpenFilePreview === next.onOpenFilePreview
    && previous.onForkFromMessage === next.onForkFromMessage
  );
@@ -5,6 +5,7 @@ import { useTranslation } from "react-i18next";

 import { FilePreviewAvailabilityProvider } from "@/components/FilePreviewAvailabilityContext";
 import { FilePreviewPanel } from "@/components/FilePreviewPanel";
+import { SessionHandleHighlight } from "@/components/CliAppMentionText";
 import { PromptNavigator } from "@/components/thread/PromptNavigator";
 import { SessionInfoPopover } from "@/components/thread/SessionInfoPopover";
 import { ThreadComposer } from "@/components/thread/ThreadComposer";
@@ -36,6 +37,7 @@ import type { CanonicalRunSnapshot, StreamError } from "@/lib/nanobot-client";
 import { inferProviderFromModelName, providerDisplayLabel } from "@/lib/provider-brand";
 import type {
  ChatSummary,
+  SessionHandle,
  SettingsPayload,
  SlashCommand,
  SkillSummary,
@@ -637,7 +639,7 @@ export function ThreadShell({
  const { t } = useTranslation();
  const chatId = session?.chatId ?? null;
  const historyKey = temporary ? null : session?.key ?? null;
-  const mentionSessions = useMemo(
+  const referenceSessions = useMemo(
    () => sessions.filter((candidate) => (
      candidate.key !== historyKey
      && (
@@ -647,6 +649,18 @@ export function ThreadShell({
    )),
    [historyKey, sessions, workspaceScope],
  );
+  const handleSessions = useMemo(() => {
+    if (temporary) return [];
+    return sessions;
+  }, [sessions, temporary]);
+  const sessionDirectory = useMemo<SessionHandle[]>(() => {
+    const handles = new Map<string, SessionHandle>();
+    if (session?.handle) handles.set(session.handle.id, session.handle);
+    for (const candidate of handleSessions) {
+      if (candidate.handle) handles.set(candidate.handle.id, candidate.handle);
+    }
+    return [...handles.values()];
+  }, [handleSessions, session?.handle]);
  const {
    messages: historical,
    loading,
@@ -1316,7 +1330,14 @@ export function ThreadShell({
      setPendingFirstTargetChatId(newId);
      return true;
    },
-    [booting, client, localModelPreset, onCreateChat, withWorkspaceScope, workspaceScope],
+    [
+      booting,
+      client,
+      localModelPreset,
+      onCreateChat,
+      withWorkspaceScope,
+      workspaceScope,
+    ],
  );

  const handleThreadSend = useCallback(
@@ -1469,7 +1490,8 @@ export function ThreadShell({
          slashCommands={availableSlashCommands}
          cliApps={cliApps}
          mcpPresets={mcpPresets}
-          sessions={mentionSessions}
+          sessions={referenceSessions}
+          handleSessions={handleSessions}
          skills={skills}
          onStop={stop}
          onTranscribeAudio={transcribeAudio}
@@ -1516,7 +1538,8 @@ export function ThreadShell({
          slashCommands={availableSlashCommands}
          cliApps={cliApps}
          mcpPresets={mcpPresets}
-          sessions={mentionSessions}
+          sessions={referenceSessions}
+          handleSessions={handleSessions}
          skills={skills}
          surfaceRef={composerSurfaceRef}
          onTranscribeAudio={transcribeAudio}
@@ -1560,6 +1583,7 @@ export function ThreadShell({
  const threadHeader = !hideHeader ? (
    <ThreadHeader
      title={title}
+      handle={temporary || hideHeaderTitle ? null : session?.handle}
      onToggleSidebar={onToggleSidebar}
      theme={theme}
      onToggleTheme={onToggleTheme}
@@ -1583,6 +1607,23 @@ export function ThreadShell({
  return (
    <section ref={shellRef} className="relative flex min-h-0 flex-1 overflow-hidden">
      <div className="relative flex min-w-0 flex-1 flex-col overflow-hidden">
+        {hideHeaderTitle && !temporary && session?.handle ? (
+          <div
+            data-testid="pane-handle-identity"
+            data-active={headerActive ? "true" : "false"}
+            aria-label={`Session @${session.handle.name}`}
+            className="flex h-8 shrink-0 items-center px-3 text-[12px]"
+          >
+            <span
+              data-pane-handle-handle
+              className="shrink-0"
+            >
+              <SessionHandleHighlight handle={session.handle}>
+                @{session.handle.name}
+              </SessionHandleHighlight>
+            </span>
+          </div>
+        ) : null}
        {headerPortalTarget === undefined ? threadHeader : null}
        <FilePreviewAvailabilityProvider
          resolve={historyKey ? resolveFilePreviewAvailability : undefined}
@@ -1602,6 +1643,7 @@ export function ThreadShell({
            showScrollToBottomButton={!!session}
            cliApps={cliApps}
            mcpPresets={mcpPresets}
+            sessionDirectory={sessionDirectory}
            slashCommands={availableSlashCommands}
            forkBoundaryMessageCount={forkBoundaryMessageCount}
            hasMoreBefore={hasMoreBefore}
@@ -26,7 +26,13 @@ import {
  promptTop,
 } from "@/components/thread/promptNavigation";
 import { cn } from "@/lib/utils";
-import type { CliAppInfo, McpPresetInfo, SlashCommand, UIMessage } from "@/lib/types";
+import type {
+  CliAppInfo,
+  McpPresetInfo,
+  SessionHandle,
+  SlashCommand,
+  UIMessage,
+} from "@/lib/types";

 export interface ThreadViewportHandle {
  jumpToUserPrompt: (promptId: string) => void;
@@ -50,6 +56,7 @@ interface ThreadViewportProps {
  cliApps?: CliAppInfo[];
  mcpPresets?: McpPresetInfo[];
  slashCommands?: SlashCommand[];
+  sessionDirectory?: SessionHandle[];
  forkBoundaryMessageCount?: number | null;
  hasMoreBefore?: boolean;
  loadingOlder?: boolean;
@@ -69,6 +76,7 @@ const SOFT_KEYBOARD_MIN_INSET_PX = 80;
 const SESSION_HANDOFF_EXIT_DURATION_MS = 80;
 const SESSION_HANDOFF_ENTER_DURATION_MS = 140;
 const SESSION_HANDOFF_OPACITY = 0.82;
+const EMPTY_SESSION_DIRECTORY: SessionHandle[] = [];
 export const INITIAL_HISTORY_WINDOW = 160;
 export const HISTORY_WINDOW_INCREMENT = 120;

@@ -104,11 +112,6 @@ function isKeyboardEditableElement(element: Element | null): element is HTMLElem
  ].includes(element.type);
 }

-function isThreadDisclosureTarget(target: EventTarget | null): boolean {
-  return target instanceof Element
-    && target.closest("[data-thread-disclosure]") !== null;
-}
-
 function isKeyboardControl(element: Element | null): boolean {
  return element instanceof HTMLElement
    && element.closest(
@@ -116,6 +119,11 @@ function isKeyboardControl(element: Element | null): boolean {
    ) !== null;
 }

+function isThreadDisclosureTarget(target: EventTarget | null): boolean {
+  return target instanceof Element
+    && target.closest("[data-thread-disclosure]") !== null;
+}
+
 type ThreadScrollDirection = "backward" | "forward";

 const KEYBOARD_SCROLL_DIRECTIONS: Readonly<
@@ -185,6 +193,7 @@ export const ThreadViewport = forwardRef<ThreadViewportHandle, ThreadViewportPro
  cliApps = [],
  mcpPresets = [],
  slashCommands = [],
+  sessionDirectory = EMPTY_SESSION_DIRECTORY,
  forkBoundaryMessageCount = null,
  hasMoreBefore = false,
  loadingOlder = false,
@@ -762,6 +771,7 @@ export const ThreadViewport = forwardRef<ThreadViewportHandle, ThreadViewportPro
                  cliApps={cliApps}
                  mcpPresets={mcpPresets}
                  slashCommands={slashCommands}
+                  sessionDirectory={sessionDirectory}
                  forkBoundaryMessageCount={visibleForkBoundaryMessageCount}
                  onOpenFilePreview={onOpenFilePreview}
                  onForkFromMessage={onForkFromMessage}
@@ -15,6 +15,8 @@ export interface ToolField {
    | "key"
    | "label"
    | "name"
+    | "to"
+    | "expect_reply"
    | "channel"
    | "chat_id"
    | "session_id"
@@ -119,7 +121,7 @@ export function describeGenericToolRun(items: GenericToolRunItem[]): GenericTool
    status,
    label: activityLabel(family, status, collected, name, items),
    detail: activityDetail(items, family, name),
-    aside: activityAside(items, family),
+    aside: activityAside(items, family, name),
  };
 }

@@ -168,6 +170,7 @@ function safeFields(args: unknown): ToolField[] {
    "key",
    "label",
    "name",
+    "to",
    "channel",
    "chat_id",
    "session_id",
@@ -178,6 +181,17 @@ function safeFields(args: unknown): ToolField[] {
      fields.push({ key, value: value.trim() });
    }
  }
+  const expectReply = record.expect_reply;
+  if (typeof expectReply === "boolean") {
+    fields.push({ key: "expect_reply", value: String(expectReply) });
+  } else if (typeof expectReply === "string") {
+    const normalized = expectReply.toLowerCase();
+    if (["true", "1", "yes"].includes(normalized)) {
+      fields.push({ key: "expect_reply", value: "true" });
+    } else if (["false", "0", "no"].includes(normalized)) {
+      fields.push({ key: "expect_reply", value: "false" });
+    }
+  }
  return fields;
 }

@@ -226,6 +240,18 @@ function activityLabel(
      return statusCopy(status, "Generating image", "Generated image", "Could not generate image");
    case "spawn":
      return statusCopy(status, "Delegating task", "Delegated task", "Could not delegate task");
+    case "send_session_message":
+      if (items.length > 1) {
+        return statusCopy(
+          status,
+          "Sending messages",
+          "Sent messages",
+          "Could not send messages",
+        );
+      }
+      return fieldValue(items[0]?.trace, "expect_reply") === "true"
+        ? statusCopy(status, "Asking", "Asked", "Could not reach")
+        : statusCopy(status, "Sending to", "Sent to", "Could not reach");
    case "message":
      return statusCopy(status, "Sending message", "Sent message", "Could not send message");
    case "my":
@@ -281,6 +307,8 @@ function activityDetail(items: GenericToolRunItem[], family: ToolFamily, name: s
  switch (name) {
    case "spawn":
      return safeText(fieldValue(trace, "label"));
+    case "send_session_message":
+      return safeText(fieldValue(trace, "to"));
    case "message":
      return safeText(fieldValue(trace, "channel"));
    case "my":
@@ -301,10 +329,15 @@ function activityDetail(items: GenericToolRunItem[], family: ToolFamily, name: s
  }
 }

-function activityAside(items: GenericToolRunItem[], family: ToolFamily): string {
+function activityAside(
+  items: GenericToolRunItem[],
+  family: ToolFamily,
+  name: string,
+): string {
  const pathCount = uniqueValues(items, ["path", "file_path"]).length;
  if (pathCount > 1) return `${pathCount} files`;
  if (items.length <= 1) return "";
+  if (name === "send_session_message") return `${items.length} messages`;
  if (family === "content-search" || family === "file-search" || family === "memory") {
    return `${items.length} searches`;
  }
@@ -33,6 +33,14 @@
    --input: 40 8% 90.5%;
    --ring: 0 0% 3.9%;
    --inline-token-highlight: #ef8e30;
+    --session-handle-0: #b45f36;
+    --session-handle-1: #9b6b16;
+    --session-handle-2: #3f7a4f;
+    --session-handle-3: #267b78;
+    --session-handle-4: #3c6fa8;
+    --session-handle-5: #655fb0;
+    --session-handle-6: #98558f;
+    --session-handle-7: #a54f62;
    --temporary-control-active: #ef8e30;
    --temporary-accent: 24 95% 53%;
    --temporary-foreground: 17 88% 32%;
@@ -81,6 +89,14 @@
    --input: var(--border);
    --ring: 0 0% 83.1%;
    --inline-token-highlight: #ef8e30;
+    --session-handle-0: #e58a62;
+    --session-handle-1: #d2a44d;
+    --session-handle-2: #73b985;
+    --session-handle-3: #55b8b2;
+    --session-handle-4: #72a5dc;
+    --session-handle-5: #9a91e3;
+    --session-handle-6: #cf83c5;
+    --session-handle-7: #dc7e91;
    --temporary-control-active: #ef8e30;
    --temporary-accent: 24 95% 53%;
    --temporary-foreground: 32 98% 73%;
@@ -33,6 +33,7 @@ import type {
  OutboundCliAppMention,
  OutboundMcpPresetMention,
  OutboundMedia,
+  SessionHandle,
  SessionMention,
  GoalStateWsPayload,
  MessageDeliveryStatus,
@@ -169,6 +170,7 @@ export interface SendOptions {
  cliApps?: OutboundCliAppMention[];
  mcpPresets?: OutboundMcpPresetMention[];
  sessionMentions?: SessionMention[];
+  sessionHandles?: SessionHandle[];
  quotedContext?: string;
  workspaceScope?: WorkspaceScopePayload | null;
  sideChannel?: boolean;
@@ -188,6 +190,7 @@ function eventExtendsModelActivity(ev: InboundEvent): boolean {
    ev.event === "delta"
    || ev.event === "reasoning_delta"
    || ev.event === "file_edit"
+    || ev.event === "session_message"
  ) return true;
  return ev.event === "message"
    && (ev.kind === "tool_hint" || ev.kind === "progress" || ev.kind === "reasoning");
@@ -218,6 +221,33 @@ function transitionTurnDelivery(
  return changed ? next : messages;
 }

+function appendLiveSessionMessage(
+  messages: UIMessage[],
+  event: Extract<InboundEvent, { event: "session_message" }>,
+): UIMessage[] {
+  const messageId = event.session_message?.message_id?.trim();
+  if (!messageId || event.session_message.direction !== "incoming") return messages;
+  if (messages.some((message) => message.sessionMessage?.message_id === messageId)) return messages;
+
+  const row: UIMessage = {
+    id: `session-message:${messageId}`,
+    role: "user",
+    content: event.text,
+    createdAt: Number.isFinite(event.created_at_ms) ? event.created_at_ms : Date.now(),
+    sessionMessage: event.session_message,
+    ...turnFieldsFromEvent(event, "user"),
+  };
+  const sameTurnIndex = event.turn_id
+    ? messages.findIndex((message) => message.turnId === event.turn_id)
+    : -1;
+  if (sameTurnIndex < 0) return [...messages, row];
+  return [
+    ...messages.slice(0, sameTurnIndex),
+    row,
+    ...messages.slice(sameTurnIndex),
+  ];
+}
+
 export function useNanobotStream(
  chatId: string | null,
  initialMessages: UIMessage[] = [],
@@ -645,6 +675,18 @@ export function useNanobotStream(
    });
  }, [cancelStreamEndTimer, client]);

+  useEffect(() => {
+    return client.onRunStatus((updatedChatId, startedAt) => {
+      if (updatedChatId !== chatId) return;
+      // Canonical HTTP reconciliation can settle a turn before its delayed
+      // WebSocket completion frame reaches this mounted thread. The client
+      // then fences that duplicate frame, so keep the pane-local timer in
+      // sync with the client's authoritative per-chat run projection.
+      setRunStartedAt(startedAt);
+      if (startedAt !== null) setIsStreaming(true);
+    });
+  }, [chatId, client]);
+
  // Reset local state when switching chats. Do not reset on every
  // ``initialMessages`` update: a brand-new chat can receive an empty/404
  // history response after the optimistic first message has already rendered.
@@ -802,12 +844,20 @@ export function useNanobotStream(

      const shouldCloseAnswerBeforeEvent =
        ev.event === "file_edit"
+        || ev.event === "session_message"
        || (
          ev.event === "message"
          && (ev.kind === "tool_hint" || ev.kind === "progress")
        );
      flushPendingStreamEvents({ closeAnswerSegment: shouldCloseAnswerBeforeEvent });

+      if (ev.event === "session_message") {
+        clearActivitySegment();
+        setIsStreaming(true);
+        setMessages((prev) => appendLiveSessionMessage(prev, ev));
+        return;
+      }
+
      if (ev.event === "reasoning_end") {
        if (suppressStreamUntilTurnEndRef.current) return;
        setMessages((prev) => closeReasoningStream(prev, Date.now()));
@@ -1138,6 +1188,9 @@ export function useNanobotStream(
            ...(options?.sessionMentions?.length
              ? { sessionMentions: options.sessionMentions }
              : {}),
+            ...(options?.sessionHandles?.length
+              ? { sessionHandles: options.sessionHandles }
+              : {}),
          },
        ];
      });
@@ -1180,7 +1180,6 @@
      "placeholderStreaming": "Model is responding…",
      "inputAria": "Message input",
      "sendHint": "Enter to send · Shift+Enter for newline",
-      "runRuntimeTitle": "Running · {{elapsed}}",
      "goalStateStrip": "Goal · {{label}}",
      "goalStateFallback": "Goal",
      "goalStateExpandAria": "Show full goal",
@@ -1324,9 +1323,7 @@
        "cliDescription": "Use @{{name}} as a local CLI app",
        "mcpDescription": "Use @{{name}} as an MCP server",
        "cliTitle": "CLI app: {{name}}",
-        "mcpTitle": "MCP server: {{name}}",
-        "sessionBadge": "Nanobot conversation",
-        "sessionDescription": "Reference @{{name}} as a previous chat"
+        "mcpTitle": "MCP server: {{name}}"
      },
      "encoding": "Encoding…",
      "remove": "Remove attachment",
@@ -1167,7 +1167,6 @@
      "placeholderStreaming": "El modelo está respondiendo…",
      "inputAria": "Entrada de mensaje",
      "sendHint": "Enter para enviar · Shift+Enter para nueva línea",
-      "runRuntimeTitle": "En ejecución · {{elapsed}}",
      "goalStateStrip": "Objetivo · {{label}}",
      "goalStateFallback": "Objetivo",
      "goalStateExpandAria": "Ver objetivo completo",
@@ -1327,9 +1326,7 @@
        "cliDescription": "Usar @{{name}} como aplicación CLI local",
        "mcpDescription": "Usar @{{name}} como servidor MCP",
        "cliTitle": "Aplicación CLI: {{name}}",
-        "mcpTitle": "Servidor MCP: {{name}}",
-        "sessionBadge": "Conversación de Nanobot",
-        "sessionDescription": "Referenciar @{{name}} como chat anterior"
+        "mcpTitle": "Servidor MCP: {{name}}"
      },
      "workspace": {
        "accessAria": "Modo de acceso al espacio de trabajo",
@@ -1166,7 +1166,6 @@
      "placeholderStreaming": "Le modèle est en train de répondre…",
      "inputAria": "Champ de message",
      "sendHint": "Entrée pour envoyer · Maj+Entrée pour un retour à la ligne",
-      "runRuntimeTitle": "Exécution · {{elapsed}}",
      "goalStateStrip": "Objectif · {{label}}",
      "goalStateFallback": "Objectif",
      "goalStateExpandAria": "Afficher l’objectif complet",
@@ -1326,9 +1325,7 @@
        "cliDescription": "Utiliser @{{name}} comme application CLI locale",
        "mcpDescription": "Utiliser @{{name}} comme serveur MCP",
        "cliTitle": "Application CLI : {{name}}",
-        "mcpTitle": "Serveur MCP : {{name}}",
-        "sessionBadge": "Conversation Nanobot",
-        "sessionDescription": "Référencer @{{name}} comme discussion précédente"
+        "mcpTitle": "Serveur MCP : {{name}}"
      },
      "workspace": {
        "accessAria": "Mode d’accès à l’espace de travail",
@@ -1166,7 +1166,6 @@
      "placeholderStreaming": "Model sedang merespons…",
      "inputAria": "Input pesan",
      "sendHint": "Enter untuk kirim · Shift+Enter untuk baris baru",
-      "runRuntimeTitle": "Berjalan · {{elapsed}}",
      "goalStateStrip": "Tujuan · {{label}}",
      "goalStateFallback": "Tujuan",
      "goalStateExpandAria": "Lihat tujuan lengkap",
@@ -1326,9 +1325,7 @@
        "cliDescription": "Gunakan @{{name}} sebagai aplikasi CLI lokal",
        "mcpDescription": "Gunakan @{{name}} sebagai server MCP",
        "cliTitle": "Aplikasi CLI: {{name}}",
-        "mcpTitle": "Server MCP: {{name}}",
-        "sessionBadge": "Percakapan Nanobot",
-        "sessionDescription": "Referensikan @{{name}} sebagai chat sebelumnya"
+        "mcpTitle": "Server MCP: {{name}}"
      },
      "workspace": {
        "accessAria": "Mode akses ruang kerja",
@@ -1166,7 +1166,6 @@
      "placeholderStreaming": "モデルが応答しています…",
      "inputAria": "メッセージ入力欄",
      "sendHint": "Enter で送信 · Shift+Enter で改行",
-      "runRuntimeTitle": "実行中 · {{elapsed}}",
      "goalStateStrip": "目標 · {{label}}",
      "goalStateFallback": "目標",
      "goalStateExpandAria": "目標の全文を表示",
@@ -1326,9 +1325,7 @@
        "cliDescription": "@{{name}} をローカル CLI アプリとして使用",
        "mcpDescription": "@{{name}} を MCP サーバーとして使用",
        "cliTitle": "CLI アプリ: {{name}}",
-        "mcpTitle": "MCP サーバー: {{name}}",
-        "sessionBadge": "Nanobot の会話",
-        "sessionDescription": "@{{name}} を過去のチャットとして参照"
+        "mcpTitle": "MCP サーバー: {{name}}"
      },
      "workspace": {
        "accessAria": "ワークスペースのアクセスモード",
@@ -1166,7 +1166,6 @@
      "placeholderStreaming": "모델이 응답 중입니다…",
      "inputAria": "메시지 입력",
      "sendHint": "Enter로 전송 · Shift+Enter로 줄바꿈",
-      "runRuntimeTitle": "실행 중 · {{elapsed}}",
      "goalStateStrip": "목표 · {{label}}",
      "goalStateFallback": "목표",
      "goalStateExpandAria": "전체 목표 보기",
@@ -1326,9 +1325,7 @@
        "cliDescription": "@{{name}}을 로컬 CLI 앱으로 사용",
        "mcpDescription": "@{{name}}을 MCP 서버로 사용",
        "cliTitle": "CLI 앱: {{name}}",
-        "mcpTitle": "MCP 서버: {{name}}",
-        "sessionBadge": "Nanobot 대화",
-        "sessionDescription": "@{{name}}을 이전 채팅으로 참조"
+        "mcpTitle": "MCP 서버: {{name}}"
      },
      "workspace": {
        "accessAria": "작업공간 접근 모드",
@@ -1180,7 +1180,6 @@
      "placeholderStreaming": "O modelo está respondendo…",
      "inputAria": "Campo de mensagem",
      "sendHint": "Enter para enviar · Shift+Enter para nova linha",
-      "runRuntimeTitle": "Executando · {{elapsed}}",
      "goalStateStrip": "Objetivo · {{label}}",
      "goalStateFallback": "Objetivo",
      "goalStateExpandAria": "Mostrar objetivo completo",
@@ -1324,9 +1323,7 @@
        "cliDescription": "Usar @{{name}} como aplicativo CLI local",
        "mcpDescription": "Usar @{{name}} como servidor MCP",
        "cliTitle": "Aplicativo CLI: {{name}}",
-        "mcpTitle": "Servidor MCP: {{name}}",
-        "sessionBadge": "Conversa do Nanobot",
-        "sessionDescription": "Referenciar @{{name}} como chat anterior"
+        "mcpTitle": "Servidor MCP: {{name}}"
      },
      "encoding": "Codificando…",
      "remove": "Remover anexo",
@@ -1166,7 +1166,6 @@
      "placeholderStreaming": "Mô hình đang trả lời…",
      "inputAria": "Ô nhập tin nhắn",
      "sendHint": "Enter để gửi · Shift+Enter để xuống dòng",
-      "runRuntimeTitle": "Đang chạy · {{elapsed}}",
      "goalStateStrip": "Mục tiêu · {{label}}",
      "goalStateFallback": "Mục tiêu",
      "goalStateExpandAria": "Xem đầy đủ mục tiêu",
@@ -1326,9 +1325,7 @@
        "cliDescription": "Dùng @{{name}} như ứng dụng CLI cục bộ",
        "mcpDescription": "Dùng @{{name}} như máy chủ MCP",
        "cliTitle": "Ứng dụng CLI: {{name}}",
-        "mcpTitle": "Máy chủ MCP: {{name}}",
-        "sessionBadge": "Cuộc trò chuyện Nanobot",
-        "sessionDescription": "Tham chiếu @{{name}} như cuộc trò chuyện trước"
+        "mcpTitle": "Máy chủ MCP: {{name}}"
      },
      "workspace": {
        "accessAria": "Chế độ truy cập không gian làm việc",
@@ -1180,7 +1180,6 @@
      "placeholderStreaming": "模型正在回复…",
      "inputAria": "消息输入框",
      "sendHint": "Enter 发送 · Shift+Enter 换行",
-      "runRuntimeTitle": "运行中 · {{elapsed}}",
      "goalStateStrip": "目标 · {{label}}",
      "goalStateFallback": "目标",
      "goalStateExpandAria": "查看完整目标",
@@ -1323,9 +1322,7 @@
        "cliDescription": "使用 @{{name}} 调用本地 CLI",
        "mcpDescription": "使用 @{{name}} 调用 MCP 服务",
        "cliTitle": "CLI 应用：{{name}}",
-        "mcpTitle": "MCP 服务：{{name}}",
-        "sessionBadge": "Nanobot 对话",
-        "sessionDescription": "引用历史会话 @{{name}}"
+        "mcpTitle": "MCP 服务：{{name}}"
      },
      "encoding": "处理中…",
      "remove": "移除附件",
@@ -1166,7 +1166,6 @@
      "placeholderStreaming": "模型正在回覆…",
      "inputAria": "訊息輸入框",
      "sendHint": "Enter 送出 · Shift+Enter 換行",
-      "runRuntimeTitle": "執行中 · {{elapsed}}",
      "goalStateStrip": "目標 · {{label}}",
      "goalStateFallback": "目標",
      "goalStateExpandAria": "檢視完整目標",
@@ -1326,9 +1325,7 @@
        "cliDescription": "將 @{{name}} 作為本機 CLI 應用程式使用",
        "mcpDescription": "將 @{{name}} 作為 MCP 伺服器使用",
        "cliTitle": "CLI 應用程式：{{name}}",
-        "mcpTitle": "MCP 伺服器：{{name}}",
-        "sessionBadge": "Nanobot 對話",
-        "sessionDescription": "引用先前的對話 @{{name}}"
+        "mcpTitle": "MCP 伺服器：{{name}}"
      },
      "workspace": {
        "accessAria": "工作區存取模式",
@@ -23,6 +23,7 @@ import type {
  ProviderOAuthLoginResult,
  ProviderSettingsUpdate,
  SessionDeleteResult,
+  SessionListHandle,
  SessionAutomationsPayload,
  SettingsPayload,
  SettingsUpdate,
@@ -166,6 +167,22 @@ function splitKey(key: string): { channel: string; chatId: string } {
  return { channel: key.slice(0, idx), chatId: key.slice(idx + 1) };
 }

+function normalizeSessionListHandle(value: unknown): SessionListHandle | null {
+  if (!value || typeof value !== "object") return null;
+  const handle = value as Partial<SessionListHandle>;
+  const id = typeof handle.id === "string" ? handle.id.trim() : "";
+  const name = typeof handle.name === "string" ? handle.name.trim() : "";
+  if (
+    !/^handle_[a-f0-9]{32}$/i.test(id)
+    || !name
+    || !/^[\p{L}\p{N}_-]+$/u.test(name)
+    || !Number.isInteger(handle.color_slot)
+    || (handle.color_slot ?? -1) < 0
+    || (handle.color_slot ?? 8) >= 8
+  ) return null;
+  return { id, name, color_slot: handle.color_slot as number };
+}
+
 export async function listSessions(
  token: string,
  base: string = "",
@@ -179,6 +196,7 @@ export async function listSessions(
    model_preset?: string | null;
    run_started_at?: number | null;
    workspace_scope?: WorkspaceScopePayload | null;
+    handle?: SessionListHandle | null;
  };
  const body = await request<{ sessions: Row[] }>(
    `${base}/api/sessions`,
@@ -186,17 +204,22 @@ export async function listSessions(
    undefined,
    API_READ_TIMEOUT_MS,
  );
-  return body.sessions.map((s) => ({
-    key: s.key,
-    ...splitKey(s.key),
-    createdAt: s.created_at,
-    updatedAt: s.updated_at,
-    title: s.title ?? "",
-    preview: s.preview ?? "",
-    modelPreset: s.model_preset ?? null,
-    runStartedAt: s.run_started_at ?? null,
-    workspaceScope: s.workspace_scope ?? null,
-  }));
+  return body.sessions.map((s) => {
+    const rawSession = normalizeSessionListHandle(s.handle);
+    const handle = rawSession ? { ...rawSession, session_key: s.key } : null;
+    return {
+      key: s.key,
+      ...splitKey(s.key),
+      createdAt: s.created_at,
+      updatedAt: s.updated_at,
+      title: s.title ?? "",
+      preview: s.preview ?? "",
+      modelPreset: s.model_preset ?? null,
+      runStartedAt: s.run_started_at ?? null,
+      workspaceScope: s.workspace_scope ?? null,
+      handle,
+    };
+  });
 }

 /** Disk-backed WebUI display thread snapshot (separate from agent session). */
@@ -5,6 +5,7 @@ import type {
  OutboundCliAppMention,
  OutboundMcpPresetMention,
  OutboundMedia,
+  SessionHandle,
  SessionMention,
  SidebarStatePayload,
  GoalStateWsPayload,
@@ -195,7 +196,7 @@ export class NanobotClient {
  private knownChats = new Set<string>();
  /** Temporary chats are connection-owned and intentionally not reattached. */
  private temporaryChatIds = new Set<string>();
-  /** Wall-clock run strip: updated from ``goal_status`` even with no ``onChat`` subscriber. */
+  /** Per-chat run projection, started optimistically and reconciled by lifecycle events. */
  private runStartedAtByChatId = new Map<string, number>();
  /** Per-turn clocks let a rejected newer turn fall back without borrowing its timer. */
  private runStartedAtByTurnKey = new Map<string, number>();
@@ -537,6 +538,14 @@ export class NanobotClient {
    }
  }

+  private startRunLocally(chatId: string, turnId: string): void {
+    const startedAt = Date.now() / 1000;
+    this.runStartedAtByTurnKey.set(this.runSendKey(chatId, turnId), startedAt);
+    const previous = this.runStartedAtByChatId.get(chatId);
+    this.runStartedAtByChatId.set(chatId, startedAt);
+    if (previous !== startedAt) this.emitRunStatus(chatId, startedAt);
+  }
+
  private settleRunTurn(chatId: string, turnId?: string): void {
    if (!turnId) return;
    this.clearPendingMessageSend(chatId, turnId);
@@ -716,7 +725,7 @@ export class NanobotClient {
    }
  }

-  private recordGoalStatusForRunStrip(chatId: string, ev: InboundEvent): void {
+  private recordRunStatus(chatId: string, ev: InboundEvent): void {
    if (ev.event === "turn_end") {
      this.recordRunCompletion(chatId, ev.turn_id);
      return;
@@ -967,6 +976,7 @@ export class NanobotClient {
      cliApps?: OutboundCliAppMention[];
      mcpPresets?: OutboundMcpPresetMention[];
      sessionMentions?: SessionMention[];
+      sessionHandles?: SessionHandle[];
      quotedContext?: string;
      workspaceScope?: WorkspaceScopePayload | null;
      turnId?: string;
@@ -986,6 +996,9 @@ export class NanobotClient {
      ...(options?.sessionMentions?.length
        ? { session_mentions: options.sessionMentions }
        : {}),
+      ...(options?.sessionHandles?.length
+        ? { session_handles: options.sessionHandles }
+        : {}),
      ...(options?.quotedContext?.trim() ? { quoted_context: options.quotedContext.trim() } : {}),
      ...(options?.workspaceScope ? { workspace_scope: options.workspaceScope } : {}),
      ...(options?.turnId ? { turn_id: options.turnId } : {}),
@@ -1004,7 +1017,10 @@ export class NanobotClient {
    }
    if (options?.turnId && !isSystemCommandTurnId(options.turnId)) {
      const startsNewRun = options.startsNewRun !== false;
-      if (startsNewRun) this.advanceRunGeneration(chatId, options.turnId);
+      if (startsNewRun) {
+        this.advanceRunGeneration(chatId, options.turnId);
+        this.startRunLocally(chatId, options.turnId);
+      }
      this.trackPendingMessageSend(chatId, options.turnId, startsNewRun);
    }
    this.queueSend(frame);
@@ -1240,7 +1256,7 @@ export class NanobotClient {
    if (chatId) {
      if (this.isCanonicalCompletedTurnEvent(chatId, parsed)) return;
      const supersededRunCompletion = this.isSupersededRunCompletion(chatId, parsed);
-      this.recordGoalStatusForRunStrip(chatId, parsed);
+      this.recordRunStatus(chatId, parsed);
      if (supersededRunCompletion) return;
      this.recordGoalStateSnapshot(chatId, parsed);
      this.dispatch(chatId, parsed);
@@ -66,6 +66,8 @@ export interface UIMessage {
  mcpPresets?: UIMcpPresetAttachment[];
  /** Persisted sessions explicitly referenced by this user turn. */
  sessionMentions?: SessionMention[];
+  /** Active session handles structurally selected by this user turn. */
+  sessionHandles?: SessionHandle[];
  /** Assistant turn: accumulated model reasoning / thinking text. Built up
   * incrementally from ``reasoning_delta`` frames; finalized when
   * ``reasoning_end`` arrives. */
@@ -79,6 +81,8 @@ export interface UIMessage {
  completedAt?: number;
  /** Lightweight provenance for proactive assistant messages. */
  source?: UIMessageSource;
+  /** Structured provenance for a message delivered by another session. */
+  sessionMessage?: UISessionMessage;
  /** Stable protocol metadata for grouping all activity emitted by one user turn. */
  turnId?: string;
  turnPhase?: UITurnPhase;
@@ -110,13 +114,31 @@ export interface UIMcpPresetAttachment {
 }

 export interface SessionMention {
-  /** Text token inserted in the composer, without the leading @. */
+  /** Text token inserted in the composer, without the leading #. */
  name: string;
  /** Stable persisted-session identifier used by read_session. */
  session_key: string;
  title: string;
 }

+/** Exact public handle DTO returned by the session-list endpoint. */
+export interface SessionListHandle {
+  id: string;
+  name: string;
+  color_slot: number;
+}
+
+/** Public session handle enriched with its UI navigation target. */
+export interface SessionHandle extends SessionListHandle {
+  session_key: string;
+}
+
+export interface UISessionMessage {
+  direction: "incoming" | "outgoing";
+  message_id: string;
+  session: SessionListHandle;
+}
+
 export interface SessionAutomationJob {
  id: string;
  name: string;
@@ -337,6 +359,8 @@ export interface ChatSummary {
  /** Unix epoch seconds when this session currently has a turn in flight. */
  runStartedAt?: number | null;
  workspaceScope?: WorkspaceScopePayload | null;
+  /** Stable, server-owned @handle for this session. */
+  handle?: SessionHandle | null;
 }

 export type WorkspaceAccessMode = "restricted" | "full";
@@ -1248,6 +1272,13 @@ export type InboundEvent =
      /** Optional structured payload on progress frames (channel-specific). */
      agent_ui?: AgentUIBlob;
    } & InboundTurnMetadata)
+  | ({
+      event: "session_message";
+      chat_id: string;
+      text: string;
+      created_at_ms: number;
+      session_message: UISessionMessage;
+    } & InboundTurnMetadata)
  | ({
      event: "file_edit";
      chat_id: string;
@@ -1442,6 +1473,7 @@ export type Outbound =
      cli_apps?: OutboundCliAppMention[];
      mcp_presets?: OutboundMcpPresetMention[];
      session_mentions?: SessionMention[];
+      session_handles?: SessionHandle[];
      quoted_context?: string;
      workspace_scope?: WorkspaceScopePayload;
      turn_id?: string;
@@ -1049,7 +1049,7 @@ describe("webui API helpers", () => {
    );
  });

-  it("maps generated session titles from the sessions list", async () => {
+  it("maps title-free handle handles", async () => {
    vi.mocked(fetch).mockResolvedValueOnce({
      ok: true,
      json: async () => ({
@@ -1061,6 +1061,11 @@ describe("webui API helpers", () => {
            title: "优化 WebUI 标题",
            model_preset: "fast",
            run_started_at: 1_700_000_000,
+            handle: {
+              id: "handle_1234567890abcdef1234567890abcdef",
+              name: "webui-review",
+              color_slot: 5,
+            },
          },
        ],
      }),
@@ -1073,10 +1078,39 @@ describe("webui API helpers", () => {
        preview: "",
        modelPreset: "fast",
        runStartedAt: 1_700_000_000,
+        handle: {
+          id: "handle_1234567890abcdef1234567890abcdef",
+          name: "webui-review",
+          color_slot: 5,
+          session_key: "websocket:chat-1",
+        },
      },
    ]);
  });

+  it("rejects malformed session-list handle DTOs instead of trusting enriched fields", async () => {
+    vi.mocked(fetch).mockResolvedValueOnce({
+      ok: true,
+      json: async () => ({
+        sessions: [
+          {
+            key: "websocket:chat-1",
+            created_at: null,
+            updated_at: null,
+            handle: {
+              id: "handle_1234567890abcdef1234567890abcdef",
+              name: "valid-handle",
+              color_slot: 8,
+              session_key: "websocket:attacker-controlled",
+            },
+          },
+        ],
+      }),
+    } as Response);
+
+    await expect(listSessions("tok")).resolves.toMatchObject([{ handle: null }]);
+  });
+
  it("maps slash command metadata from the commands endpoint", async () => {
    vi.mocked(fetch).mockResolvedValueOnce({
      ok: true,
@@ -519,7 +519,7 @@ describe("App layout", () => {

    await waitFor(() => expect(connectSpy).toHaveBeenCalled());
    const firstMessage = "keep this first turn visible";
-    fireEvent.change(screen.getByRole("textbox", { name: "Message input" }), {
+    fireEvent.change(screen.getByRole("combobox", { name: "Message input" }), {
      target: { value: firstMessage },
    });
    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
@@ -3375,7 +3375,7 @@ describe("App layout", () => {
      .toEqual(["Alpha", "New topic"]);

    const activeComposer = screen.getByTestId("active-pane-composer");
-    const paneInput = within(activeComposer).getByRole("textbox", {
+    const paneInput = within(activeComposer).getByRole("combobox", {
      name: "Message New topic",
    });
    expect(paneInput).toHaveClass("min-h-[50px]");
@@ -66,6 +66,104 @@ describe("ChatList", () => {
    expect(onTogglePin).toHaveBeenCalledWith("websocket:review");
  });

+  it("keeps each handle handle visible beside its conversation title", () => {
+    render(
+      <ChatList
+        sessions={[session({
+          chatId: "review",
+          title: "Review the patch",
+          handle: {
+            id: "handle_1234",
+            name: "mira",
+            color_slot: 3,
+            session_key: "websocket:review",
+          },
+        })]}
+        activeKey="websocket:review"
+        onSelect={vi.fn()}
+        onRequestDelete={vi.fn()}
+        onTogglePin={vi.fn()}
+        onRequestRename={vi.fn()}
+        onToggleArchive={vi.fn()}
+      />,
+    );
+
+    const conversation = screen.getByRole("button", {
+      name: "@mira Review the patch",
+    });
+    expect(conversation).toHaveTextContent("Review the patch");
+    expect(conversation).toHaveTextContent("@mira");
+    expect(conversation.querySelector("[data-sidebar-handle-handle]"))
+      .toHaveClass("max-w-20", "shrink-0");
+    const handle = conversation.querySelector("[data-sidebar-handle-handle]");
+    expect(handle?.querySelector("[aria-hidden]")).toBeNull();
+    const decoration = handle?.querySelector("span[style*='border-bottom-color']");
+    expect(decoration?.getAttribute("style"))
+      .toContain("var(--session-handle-3)");
+    expect(decoration?.querySelector("[data-testid], .text-foreground"))
+      .toHaveClass("text-foreground");
+    const selectionTrack = conversation.querySelector("[data-sidebar-selection-track]");
+    expect(selectionTrack).toHaveAttribute("data-active", "true");
+    expect(selectionTrack?.getAttribute("style")).toContain("var(--session-handle-3)");
+  });
+
+  it("keeps aligned handle handles when conversations become grouped panes", () => {
+    const mira = {
+      id: "handle_1234",
+      name: "mira",
+      color_slot: 3,
+      session_key: "websocket:root",
+    };
+    const nora = {
+      id: "handle_5678",
+      name: "nora",
+      color_slot: 5,
+      session_key: "websocket:child",
+    };
+    render(
+      <ChatList
+        sessions={[session({
+          key: "tab:group",
+          chatId: "workbench-tab:group",
+          title: "Grouped work",
+        })]}
+        activeKey="websocket:root"
+        paneGroups={{
+          "tab:group": {
+            tabKey: "tab:group",
+            title: "Grouped work",
+            activePaneKey: "websocket:root",
+            visible: true,
+            panes: [
+              { key: "websocket:root", chatId: "root", title: "Short", handle: mira },
+              {
+                key: "websocket:child",
+                chatId: "child",
+                title: "A much longer conversation title",
+                handle: nora,
+              },
+            ],
+          },
+        }}
+        onSelect={vi.fn()}
+        onRequestDelete={vi.fn()}
+        onTogglePin={vi.fn()}
+        onRequestRename={vi.fn()}
+        onToggleArchive={vi.fn()}
+      />,
+    );
+
+    const root = screen.getByRole("button", { name: "@mira Short" });
+    const child = screen.getByRole("button", {
+      name: "@nora A much longer conversation title",
+    });
+    expect(root).toHaveTextContent("@mira");
+    expect(child).toHaveTextContent("@nora");
+    for (const handle of document.querySelectorAll("[data-sidebar-handle-handle]")) {
+      expect(handle).toHaveClass("max-w-20", "shrink-0");
+    }
+  });
+
  it("keeps tab grouping out of drag protocols while exposing inactive panes as mention sources", () => {
    render(
      <ChatList
@@ -982,8 +1080,10 @@ describe("ChatList", () => {

    const activeButton = screen.getByRole("button", { name: "Active topic" });
    expect(activeButton).toHaveAttribute("aria-current", "page");
-    expect(activeButton.querySelector("[data-sidebar-selection-track]"))
-      .toHaveClass("origin-left", "scale-x-100", "transition-transform", "bg-current");
+    const activeTrack = activeButton.querySelector("[data-sidebar-selection-track]");
+    expect(activeTrack)
+      .toHaveClass("origin-left", "scale-x-100", "transition-transform");
+    expect(activeTrack?.getAttribute("style")).toContain("currentcolor");

    rerender(
      <ChatList
@@ -23,6 +23,7 @@ describe("generic tool activity semantics", () => {
    ['generate_image({"prompt":"private launch art"})', "Generated image", ""],
    ['spawn({"label":"Research competitors","task":"private task"})', "Delegated task", "Research competitors"],
    ['message({"channel":"telegram","content":"private message"})', "Sent message", "telegram"],
+    ['send_session_message({"to":"@reviewer","content":"private message","expect_reply":true})', "Asked", "@reviewer"],
    ['my({"action":"check","key":"context_window_tokens"})', "Checked agent settings", "context_window_tokens"],
    ['my({"action":"set","key":"model","value":"private-model"})', "Updated agent settings", "model"],
    ['cron({"action":"add","name":"Daily digest","message":"private prompt"})', "Scheduled automation", "Daily digest"],
@@ -40,6 +41,60 @@ describe("generic tool activity semantics", () => {
    expect(`${presentation.label} ${presentation.detail}`).not.toMatch(/[{}]|private|tool-results/);
  });

+  it("renders a handle target once and uses plural copy for grouped messages", () => {
+    const first = parseGenericToolTrace(
+      'send_session_message({"to":"@kai","content":"first","expect_reply":false})',
+    )!;
+    const second = parseGenericToolTrace(
+      'send_session_message({"to":"@mira","content":"second","expect_reply":false})',
+    )!;
+
+    const single = describeGenericToolRun([{ trace: first, status: "done" }]);
+    expect([single.label, single.detail].filter(Boolean).join(" ")).toBe("Sent to @kai");
+
+    const grouped = describeGenericToolRun([
+      { trace: first, status: "done" },
+      { trace: second, status: "done" },
+    ]);
+    expect(grouped).toMatchObject({
+      label: "Sent messages",
+      detail: "",
+      aside: "2 messages",
+    });
+  });
+
+  it.each([
+    [true, "running", "Asking"],
+    [true, "done", "Asked"],
+    [false, "running", "Sending to"],
+    [false, "done", "Sent to"],
+    [false, "error", "Could not reach"],
+  ] as const)(
+    "describes expect_reply=%s handle activity while %s",
+    (expectReply, status, label) => {
+      const presentation = describeRun(
+        `send_session_message({"to":"@kai","content":"private","expect_reply":${expectReply}})`,
+        status,
+      );
+      expect(presentation).toMatchObject({ label, detail: "@kai" });
+    },
+  );
+
+  it.each([
+    ["true", "Asked"],
+    ["1", "Asked"],
+    ["yes", "Asked"],
+    ["false", "Sent to"],
+    ["0", "Sent to"],
+    ["no", "Sent to"],
+  ])("matches backend boolean casting for expect_reply=%s", (expectReply, label) => {
+    const presentation = describeRun(
+      `send_session_message({"to":"@kai","content":"private","expect_reply":"${expectReply}"})`,
+      "done",
+    );
+    expect(presentation).toMatchObject({ label, detail: "@kai" });
+  });
+
  it.each([
    ["running", "Generating image"],
    ["done", "Generated image"],
@@ -28,6 +28,53 @@ describe("MarkdownTextRenderer", () => {
    );
  });

+  it("highlights only known handle handles in prose with their identity color", () => {
+    render(
+      <MarkdownTextRenderer
+        sessionHandles={[{
+          id: "handle-jules",
+          name: "jules",
+          session_key: "websocket:jules",
+          color_slot: 0,
+        }]}
+      >
+        {"已直接回复 @jules；未知 @ghost；邮箱 hello@jules.test；代码 `@jules`。"}
+      </MarkdownTextRenderer>,
+    );
+
+    const mention = screen.getByTestId("message-handle-mention-jules");
+    expect(mention).toHaveTextContent("@jules");
+    expect(mention).toHaveClass("text-foreground");
+    expect(mention.parentElement?.getAttribute("style"))
+      .toContain("var(--session-handle-0)");
+    expect(mention.closest("a")).toHaveAttribute(
+      "href",
+      "#/chat/websocket%3Ajules",
+    );
+    expect(screen.getByText("@jules", { selector: "code" })).toBeInTheDocument();
+    expect(screen.getByText(/未知 @ghost/)).toBeInTheDocument();
+    expect(screen.getByText(/hello@jules\.test/)).toBeInTheDocument();
+    expect(screen.getAllByText("@jules")).toHaveLength(2);
+  });
+
+  it("does not highlight handle handles inside raw or normalized HTML", () => {
+    render(
+      <MarkdownTextRenderer
+        sessionHandles={[{
+          id: "handle-jules",
+          name: "jules",
+          session_key: "websocket:jules",
+          color_slot: 0,
+        }]}
+      >
+        {"<code>@jules</code> <span>@jules</span> <mark>@jules</mark> outside @jules"}
+      </MarkdownTextRenderer>,
+    );
+
+    expect(screen.getAllByTestId("message-handle-mention-jules")).toHaveLength(1);
+    expect(screen.getByTestId("message-handle-mention-jules")).toHaveTextContent("@jules");
+  });
+
  it("does not link non-WebUI session references", () => {
    const { container } = render(
      <MarkdownTextRenderer>
@@ -2,6 +2,7 @@ import { act, fireEvent, render, screen, waitFor } from "@testing-library/react"
 import { describe, expect, it, vi } from "vitest";

 import { MessageBubble } from "@/components/MessageBubble";
+import { preloadMarkdownText } from "@/components/MarkdownText";
 import { fmtDateTime, formatMessageEndTime } from "@/lib/format";
 import type {
  CliAppInfo,
@@ -593,11 +594,11 @@ describe("MessageBubble", () => {
    expect(screen.getByTestId("message-mcp-mention-logo-browserbase")).toBeInTheDocument();
  });

-  it("renders persisted session mentions inside sent user messages", () => {
+  it("renders new # session references as links", () => {
    const message: UIMessage = {
      id: "u-session",
      role: "user",
-      content: "Use @收费设计 as context",
+      content: "Use #收费设计",
      createdAt: Date.now(),
      sessionMentions: [{
        name: "收费设计",
@@ -608,13 +609,113 @@ describe("MessageBubble", () => {

    render(<MessageBubble message={message} />);

-    const token = screen.getByTestId("message-session-mention-收费设计");
-    expect(token).toHaveTextContent("@收费设计");
+    const token = screen.getByTestId("message-session-reference-收费设计");
+    expect(token).toHaveTextContent("#收费设计");
    expect(token).toHaveAttribute("title", "Session: 收费设计");
    expect(token.closest("a")).toHaveAttribute("href", "#/chat/websocket%3Apricing");
-    expect(token.closest("a")?.getAttribute("style")).toContain(
-      "text-decoration-color: var(--inline-token-highlight)",
+  });
+
+  it("prefers legacy @ session metadata over a same-name catalog capability", () => {
+    const message: UIMessage = {
+      id: "u-legacy-session",
+      role: "user",
+      content: "Review @zoom",
+      createdAt: Date.now(),
+      sessionMentions: [{
+        name: "zoom",
+        session_key: "websocket:zoom-notes",
+        title: "Zoom notes",
+      }],
+    };
+
+    render(<MessageBubble message={message} cliApps={CLI_APPS} />);
+
+    const token = screen.getByTestId("message-session-reference-zoom");
+    expect(token).toHaveTextContent("@zoom");
+    expect(token.closest("a")).toHaveAttribute("href", "#/chat/websocket%3Azoom-notes");
+    expect(screen.queryByTestId("message-cli-mention-zoom")).not.toBeInTheDocument();
+  });
+
+  it("keeps a new # reference distinct from a structured same-name capability", () => {
+    const message: UIMessage = {
+      id: "u-session-and-cli",
+      role: "user",
+      content: "Compare #zoom with @zoom",
+      createdAt: Date.now(),
+      sessionMentions: [{
+        name: "zoom",
+        session_key: "websocket:zoom-notes",
+        title: "Zoom notes",
+      }],
+      cliApps: [{ name: "zoom" }],
+    };
+
+    render(<MessageBubble message={message} cliApps={CLI_APPS} />);
+
+    expect(screen.getByTestId("message-session-reference-zoom")).toHaveTextContent("#zoom");
+    expect(screen.getByTestId("message-cli-mention-zoom")).toHaveTextContent("@zoom");
+  });
+
+  it("renders incoming handle input as assistant markdown with session provenance", async () => {
+    await act(async () => {
+      await preloadMarkdownText();
+    });
+    const message: UIMessage = {
+      id: "handle-input-1",
+      role: "user",
+      content: "**Please verify** the release notes.",
+      createdAt: Date.now(),
+      sessionMessage: {
+        direction: "incoming",
+        message_id: "handle-message-1",
+        session: {
+          id: "handle_reviewer",
+          name: "reviewer",
+          color_slot: 4,
+          session_key: "websocket:reviewer",
+        },
+      },
+    };
+
+    const { container } = render(
+      <MessageBubble message={message} sessionDirectory={[message.sessionMessage!.session]} />,
    );
+
+    const sessionMessage = container.querySelector('[data-handle-message="incoming"]');
+    expect(sessionMessage).toHaveClass("w-full");
+    expect(screen.getByText("Please verify").tagName).toBe("STRONG");
+    const sessionLink = screen.getByRole("link", { name: "@reviewer" });
+    expect(sessionLink).toHaveAttribute("href", "#/chat/websocket%3Areviewer");
+    const sessionRange = sessionMessage?.querySelector("[data-handle-message-body]");
+    expect(sessionRange).toHaveClass("border-s-2", "rounded-es-[16px]", "ps-2.5");
+    expect(sessionRange?.getAttribute("style")).toContain("var(--session-handle-4)");
+  });
+
+  it("renders provenance for a deleted handle as plain text", async () => {
+    await act(async () => {
+      await preloadMarkdownText();
+    });
+    const message: UIMessage = {
+      id: "handle-input-deleted",
+      role: "user",
+      content: "This message remains in history.",
+      createdAt: Date.now(),
+      sessionMessage: {
+        direction: "incoming",
+        message_id: "handle-message-deleted",
+        session: {
+          id: "handle_deleted",
+          name: "noah",
+          color_slot: 2,
+          session_key: "websocket:noah",
+        },
+      },
+    };
+
+    render(<MessageBubble message={message} sessionDirectory={[]} />);
+
+    expect(screen.getByText("@noah")).toBeInTheDocument();
+    expect(screen.queryByRole("link", { name: "@noah" })).not.toBeInTheDocument();
  });

  it("copies completed assistant replies from the action row", async () => {
@@ -504,7 +504,7 @@ describe("NanobotClient", () => {
    expect(handler).toHaveBeenCalledTimes(3);
  });

-  it("records goal_status run strip without an onChat subscriber", () => {
+  it("records canonical run status without an onChat subscriber", () => {
    const client = new NanobotClient({
      url: "ws://test",
      reconnect: false,
@@ -527,7 +527,50 @@ describe("NanobotClient", () => {
    expect(client.getRunStartedAt("chat-strip")).toBeNull();
  });

-  it("clears the local run strip immediately when a stop is requested", () => {
+  it("starts the run projection immediately when a lifecycle message is submitted", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-08-13T10:00:00.000Z"));
+    const client = new NanobotClient({
+      url: "ws://test",
+      reconnect: false,
+      socketFactory: (url) => new FakeSocket(url) as unknown as WebSocket,
+    });
+    const handler = vi.fn();
+    client.onRunStatus(handler);
+    client.connect();
+    lastSocket().fakeOpen();
+
+    client.sendMessage("chat-optimistic", "hello", undefined, {
+      turnId: "turn-optimistic",
+    });
+
+    const submittedAt = Date.now() / 1000;
+    expect(client.getRunStartedAt("chat-optimistic")).toBe(submittedAt);
+    expect(handler).toHaveBeenLastCalledWith("chat-optimistic", submittedAt);
+    expect(client.hasUnsettledRun("chat-optimistic")).toBe(true);
+  });
+
+  it("does not start a separate run projection for side-channel guidance", () => {
+    const client = new NanobotClient({
+      url: "ws://test",
+      reconnect: false,
+      socketFactory: (url) => new FakeSocket(url) as unknown as WebSocket,
+    });
+    const handler = vi.fn();
+    client.onRunStatus(handler);
+    client.connect();
+    lastSocket().fakeOpen();
+
+    client.sendMessage("chat-guidance-only", "focus here", undefined, {
+      turnId: "turn-guidance-only",
+      startsNewRun: false,
+    });
+
+    expect(client.getRunStartedAt("chat-guidance-only")).toBeNull();
+    expect(handler).not.toHaveBeenCalled();
+  });
+
+  it("clears the local run status immediately when a stop is requested", () => {
    const client = new NanobotClient({
      url: "ws://test",
      reconnect: false,
@@ -552,7 +595,7 @@ describe("NanobotClient", () => {
    expect(handler).toHaveBeenLastCalledWith("chat-stop", null);
  });

-  it("clears stale run strip when reconnecting after a dropped socket", async () => {
+  it("clears stale run status when reconnecting after a dropped socket", async () => {
    const client = new NanobotClient({
      url: "ws://test",
      reconnect: true,
@@ -578,7 +621,7 @@ describe("NanobotClient", () => {
    expect(FakeSocket.instances.length).toBeGreaterThan(1);
  });

-  it("clears run strip when a turn_end arrives without idle", () => {
+  it("clears run status when a turn_end arrives without idle", () => {
    const client = new NanobotClient({
      url: "ws://test",
      reconnect: false,
@@ -728,6 +771,7 @@ describe("NanobotClient", () => {
    expect(
      client.reconcileCanonicalCompletion("chat-rejected", requestGeneration, []),
    ).toBe(true);
+    expect(client.getRunStartedAt("chat-rejected")).toBeNull();
  });

  it("does not let an older rejection settle or stop a newer run", () => {
@@ -2062,7 +2106,7 @@ describe("NanobotClient", () => {
    );
  });

-  it("includes session mentions in outbound messages", () => {
+  it("keeps session references and handle mentions separate on the wire", () => {
    const client = new NanobotClient({
      url: "ws://test",
      reconnect: false,
@@ -2071,23 +2115,35 @@ describe("NanobotClient", () => {
    client.connect();
    lastSocket().fakeOpen();

-    client.sendMessage("chat-current", "Use @pricing", undefined, {
+    client.sendMessage("chat-current", "Use #pricing and ask @mira", undefined, {
      sessionMentions: [{
        name: "pricing",
        session_key: "websocket:pricing",
        title: "Pricing",
      }],
+      sessionHandles: [{
+        id: "handle_mira",
+        name: "mira",
+        session_key: "websocket:mira",
+        color_slot: 3,
+      }],
    });

    expect(lastSocket().sent).toContain(JSON.stringify({
      type: "message",
      chat_id: "chat-current",
-      content: "Use @pricing",
+      content: "Use #pricing and ask @mira",
      session_mentions: [{
        name: "pricing",
        session_key: "websocket:pricing",
        title: "Pricing",
      }],
+      session_handles: [{
+        id: "handle_mira",
+        name: "mira",
+        session_key: "websocket:mira",
+        color_slot: 3,
+      }],
      webui: true,
    }));
  });
@@ -127,7 +127,12 @@ const MCP_PRESETS: McpPresetInfo[] = [
  },
 ];

-function session(chatId: string, title: string, preview = ""): ChatSummary {
+function session(
+  chatId: string,
+  title: string,
+  preview = "",
+  mentionName = title,
+): ChatSummary {
  return {
    key: `websocket:${chatId}`,
    channel: "websocket",
@@ -136,6 +141,12 @@ function session(chatId: string, title: string, preview = ""): ChatSummary {
    updatedAt: null,
    title,
    preview,
+    handle: {
+      id: `handle_${chatId}`,
+      name: mentionName,
+      color_slot: 2,
+      session_key: `websocket:${chatId}`,
+    },
  };
 }

@@ -1722,30 +1733,31 @@ describe("ThreadComposer", () => {

    const input = screen.getByLabelText("Message input");
    fireEvent.change(input, {
-      target: { value: "普通文字 @收费设计", selectionStart: 10 },
+      target: { value: "普通文字 #收费设计", selectionStart: 10 },
    });
-    expect(screen.queryByTestId("composer-session-mention-收费设计")).not.toBeInTheDocument();
+    expect(screen.queryByTestId("composer-session-reference-收费设计")).not.toBeInTheDocument();
    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
-    expect(onSend).toHaveBeenLastCalledWith("普通文字 @收费设计", undefined, undefined);
+    expect(onSend).toHaveBeenLastCalledWith("普通文字 #收费设计", undefined, undefined);

    fireEvent.change(input, {
-      target: { value: "参考 @收费", selectionStart: 6 },
+      target: { value: "参考 #收费", selectionStart: 6 },
    });

    expect(screen.getByRole("group", { name: "Nanobot conversations" })).toBeInTheDocument();
-    expect(screen.getByRole("option", { name: /@收费设计/i })).toBeInTheDocument();
+    expect(screen.getByRole("option", { name: /^收费设计 #收费设计$/i }))
+      .toBeInTheDocument();
    fireEvent.keyDown(input, { key: "Tab" });

-    expect(input).toHaveValue("参考 @收费设计 ");
-    const mention = screen.getByTestId("composer-session-mention-收费设计");
-    expect(mention).toHaveTextContent("@收费设计");
+    expect(input).toHaveValue("参考 #收费设计 ");
+    const mention = screen.getByTestId("composer-session-reference-收费设计");
+    expect(mention).toHaveTextContent("#收费设计");
    expect(mention).toHaveClass("font-normal");
    expect(mention).not.toHaveClass("font-[550]");
    expect(mention.closest("a")).toBeNull();

    fireEvent.click(screen.getByRole("button", { name: "Send message" }));

-    expect(onSend).toHaveBeenCalledWith("参考 @收费设计", undefined, {
+    expect(onSend).toHaveBeenCalledWith("参考 #收费设计", undefined, {
      sessionMentions: [{
        name: "收费设计",
        session_key: "websocket:pricing",
@@ -1754,6 +1766,198 @@ describe("ThreadComposer", () => {
    });
  });

+  it("keeps a selected session reference bound across title refreshes", () => {
+    const onSend = vi.fn();
+    const target = session("planning", "Plan");
+    const { rerender } = render(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        sessions={[target]}
+      />,
+    );
+
+    const input = screen.getByLabelText("Message input");
+    fireEvent.change(input, { target: { value: "#Pla", selectionStart: 4 } });
+    fireEvent.keyDown(input, { key: "Tab" });
+
+    rerender(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        sessions={[{ ...target, title: "Renamed plan" }]}
+      />,
+    );
+
+    expect(screen.getByTestId("composer-session-reference-Plan"))
+      .toHaveTextContent("#Plan");
+    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
+    expect(onSend).toHaveBeenCalledWith("#Plan", undefined, {
+      sessionMentions: [{
+        name: "Plan",
+        session_key: "websocket:planning",
+        title: "Renamed plan",
+      }],
+    });
+  });
+
+  it("does not revive structured session identity after its token is removed", () => {
+    const onSend = vi.fn();
+    render(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        sessions={[session("pricing", "收费设计", "讨论云存储")]}
+      />,
+    );
+
+    const input = screen.getByLabelText("Message input");
+    fireEvent.change(input, {
+      target: { value: "#收费", selectionStart: 3 },
+    });
+    fireEvent.keyDown(input, { key: "Tab" });
+    expect(screen.getByTestId("composer-session-reference-收费设计")).toBeInTheDocument();
+
+    fireEvent.change(input, { target: { value: "", selectionStart: 0 } });
+    fireEvent.change(input, {
+      target: { value: "普通文字 #收费设计", selectionStart: 10 },
+    });
+
+    expect(screen.queryByTestId("composer-session-reference-收费设计")).not.toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
+    expect(onSend).toHaveBeenCalledWith("普通文字 #收费设计", undefined, undefined);
+  });
+
+  it("does not migrate a structured identity across an atomic select-all replacement", () => {
+    const onSend = vi.fn();
+    render(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        sessions={[session("pricing", "收费设计", "讨论云存储")]}
+      />,
+    );
+
+    const input = screen.getByLabelText("Message input") as HTMLTextAreaElement;
+    fireEvent.change(input, { target: { value: "#收费", selectionStart: 3 } });
+    fireEvent.keyDown(input, { key: "Tab" });
+    expect(screen.getByTestId("composer-session-reference-收费设计")).toBeInTheDocument();
+
+    input.setSelectionRange(0, input.value.length);
+    fireEvent.select(input);
+    const replacement = "普通文字 #收费设计";
+    fireEvent.change(input, {
+      target: {
+        value: replacement,
+        selectionStart: replacement.length,
+        selectionEnd: replacement.length,
+      },
+    });
+
+    expect(screen.queryByTestId("composer-session-reference-收费设计")).not.toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
+    expect(onSend).toHaveBeenCalledWith(replacement, undefined, undefined);
+  });
+
+  it("keeps same-name session references distinct from capability mentions", () => {
+    const onSend = vi.fn();
+    render(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        cliApps={CLI_APPS}
+        sessions={[session("blender-chat", "blender")]}
+      />,
+    );
+
+    const input = screen.getByLabelText("Message input");
+    fireEvent.change(input, { target: { value: "#blend", selectionStart: 6 } });
+    fireEvent.keyDown(input, { key: "Enter" });
+    expect(screen.getByTestId("composer-session-reference-blender")).toBeInTheDocument();
+
+    const next = "#blender @blend";
+    fireEvent.change(input, { target: { value: next, selectionStart: next.length } });
+    fireEvent.keyDown(input, { key: "Enter" });
+
+    expect(screen.getByTestId("composer-session-reference-blender")).toBeInTheDocument();
+    expect(screen.getByTestId("composer-cli-mention-blender")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
+    expect(onSend).toHaveBeenCalledWith("#blender @blender", undefined, {
+      cliApps: [expect.objectContaining({ name: "blender" })],
+      sessionMentions: [{
+        name: "blender",
+        session_key: "websocket:blender-chat",
+        title: "blender",
+      }],
+    });
+  });
+
+  it("drops structured session semantics when the identity leaves the current catalog", () => {
+    const onSend = vi.fn();
+    const target = session("pricing", "pricing", "", "pricing");
+    const { rerender } = render(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        sessions={[target]}
+      />,
+    );
+
+    const input = screen.getByLabelText("Message input");
+    fireEvent.change(input, { target: { value: "#pricing", selectionStart: 8 } });
+    fireEvent.keyDown(input, { key: "Enter" });
+    expect(screen.getByTestId("composer-session-reference-pricing")).toBeInTheDocument();
+
+    rerender(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        sessions={[]}
+      />,
+    );
+    expect(screen.queryByTestId("composer-session-reference-pricing")).not.toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
+    expect(onSend).toHaveBeenCalledWith("#pricing", undefined, undefined);
+  });
+
+  it("exposes mention suggestions as an aria-activedescendant combobox and ignores IME Enter", () => {
+    render(
+      <ThreadComposer
+        onSend={vi.fn()}
+        placeholder="Type your message..."
+        cliApps={CLI_APPS}
+      />,
+    );
+
+    const input = screen.getByLabelText("Message input");
+    fireEvent.change(input, { target: { value: "@", selectionStart: 1 } });
+    const combobox = screen.getByRole("combobox", { name: "Message input" });
+    const listbox = screen.getByRole("listbox", { name: "Mentions" });
+    const firstOption = screen.getByRole("option", { name: /@gimp/i });
+    expect(combobox).toHaveAttribute("aria-expanded", "true");
+    expect(combobox).toHaveAttribute("aria-controls", listbox.id);
+    expect(combobox).toHaveAttribute("aria-activedescendant", firstOption.id);
+    expect(firstOption).toHaveAttribute("tabindex", "-1");
+
+    fireEvent.keyDown(input, { key: "Enter", isComposing: true });
+    expect(input).toHaveValue("@");
+    expect(listbox).toBeInTheDocument();
+
+    fireEvent.keyDown(input, { key: "ArrowDown" });
+    const secondOption = screen.getByRole("option", { name: /@blender/i });
+    expect(combobox).toHaveAttribute("aria-activedescendant", secondOption.id);
+  });
+
+  it("keeps combobox semantics when the mention popup is closed", () => {
+    render(<ThreadComposer onSend={vi.fn()} placeholder="Type your message..." />);
+
+    const input = screen.getByRole("combobox", { name: "Message input" });
+    expect(input).toHaveAttribute("aria-autocomplete", "list");
+    expect(input).toHaveAttribute("aria-expanded", "false");
+    expect(input).not.toHaveAttribute("aria-controls");
+    expect(input).not.toHaveAttribute("aria-activedescendant");
+  });
+
  it("turns a dropped sidebar session into the shared structured mention", () => {
    const onSend = vi.fn();
    render(
@@ -1782,7 +1986,7 @@ describe("ThreadComposer", () => {

    expect(input).toHaveValue("Compare notes");
    expect(screen.getByTestId("composer-session-drag-preview"))
-      .toHaveTextContent("@收费设计");
+      .toHaveTextContent("#收费设计");

    fireEvent.dragEnd(document);
    expect(screen.queryByTestId("composer-session-drag-preview")).not.toBeInTheDocument();
@@ -1792,13 +1996,13 @@ describe("ThreadComposer", () => {

    fireEvent.drop(input, { dataTransfer });

-    expect(input).toHaveValue("Compare @收费设计 notes");
+    expect(input).toHaveValue("Compare #收费设计 notes");
    expect(screen.queryByTestId("composer-session-drag-preview")).not.toBeInTheDocument();
-    expect(screen.getByTestId("composer-session-mention-收费设计"))
-      .toHaveTextContent("@收费设计");
+    expect(screen.getByTestId("composer-session-reference-收费设计"))
+      .toHaveTextContent("#收费设计");

    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
-    expect(onSend).toHaveBeenCalledWith("Compare @收费设计 notes", undefined, {
+    expect(onSend).toHaveBeenCalledWith("Compare #收费设计 notes", undefined, {
      sessionMentions: [{
        name: "收费设计",
        session_key: "websocket:pricing",
@@ -1829,17 +2033,19 @@ describe("ThreadComposer", () => {
    expect(screen.queryByTestId("composer-session-drag-preview")).not.toBeInTheDocument();
  });

-  it("disambiguates duplicate and capability-colliding session names", () => {
+  it("uses stable handle identities without exposing session titles", () => {
+    const handles = [
+      session("a", "First planning title", "", "Plan"),
+      session("b", "Second planning title", "", "Plan-2"),
+      session("blender-chat", "3D notes", "", "Blender"),
+    ];
    render(
      <ThreadComposer
        onSend={vi.fn()}
        placeholder="Type your message..."
        cliApps={CLI_APPS}
        mcpPresets={MCP_PRESETS}
-        sessions={[
-          ...["a", "b"].map((chatId) => session(chatId, "Plan")),
-          session("blender-chat", "Blender", "3D notes"),
-        ]}
+        handleSessions={handles}
      />,
    );

@@ -1849,18 +2055,130 @@ describe("ThreadComposer", () => {
    const palette = screen.getByRole("listbox", { name: "Mentions" });
    expect(within(palette).getAllByRole("group").map((group) => (
      group.getAttribute("aria-label")
-    ))).toEqual(["CLI apps", "MCP services", "Nanobot conversations"]);
-    const options = screen.getAllByRole("option", { name: /Plan @Plan/i });
-    expect(options.map((option) => option.textContent)).toEqual([
-      expect.stringContaining("@Plan"),
-      expect.stringContaining("@Plan-chat"),
-    ]);
-    expect(screen.getByRole("group", { name: "Nanobot conversations" })).toBeInTheDocument();
+    ))).toEqual(["Nanobot conversations", "CLI apps", "MCP services"]);
+    const firstSession = screen.getByRole("option", { name: /^@Plan$/i });
+    expect(firstSession).toHaveAttribute("aria-selected", "true");
+    expect(input).toHaveAttribute("aria-activedescendant", firstSession.id);
+    expect(screen.getByRole("option", { name: /^@Plan-2$/i }))
+      .toBeInTheDocument();
+    expect(screen.getByRole("group", { name: "Nanobot conversations" }))
+      .toBeInTheDocument();
    expect(screen.getByRole("group", { name: "CLI apps" })).toBeInTheDocument();
-    expect(screen.getByRole("option", { name: /Blender @Blender-chat Reference/i }))
+    expect(screen.getByRole("option", { name: /^@Blender$/i }))
      .toBeInTheDocument();
    expect(screen.getByRole("option", { name: /Blender @blender Use/i }))
      .toBeInTheDocument();
+    expect(screen.queryByText("First planning title")).not.toBeInTheDocument();
+    expect(screen.queryByText("Second planning title")).not.toBeInTheDocument();
+  });
+
+  it("binds every same-name occurrence to one selected namespace across queue replay", () => {
+    const onSend = vi.fn();
+    const sameNameSession = session("blender-handle", "Session title", "", "blender");
+    render(
+      <ThreadComposer
+        onSend={onSend}
+        onStop={vi.fn()}
+        isStreaming
+        placeholder="Type your message..."
+        cliApps={CLI_APPS}
+        handleSessions={[sameNameSession]}
+      />,
+    );
+
+    const input = screen.getByRole("combobox", { name: "Message input" });
+    fireEvent.change(input, { target: { value: "@blend", selectionStart: 6 } });
+    fireEvent.keyDown(input, { key: "Enter" });
+    expect(screen.getByTestId("composer-handle-mention-blender")).toBeInTheDocument();
+
+    const withSecondOccurrence = "@blender then @blender";
+    fireEvent.change(input, {
+      target: { value: withSecondOccurrence, selectionStart: withSecondOccurrence.length },
+    });
+    expect(screen.getAllByTestId("composer-handle-mention-blender")).toHaveLength(2);
+
+    input.setSelectionRange("@blender then ".length, withSecondOccurrence.length);
+    fireEvent.select(input);
+    fireEvent.change(input, {
+      target: { value: "@blender then @blend", selectionStart: 20 },
+    });
+    const cliOption = screen.getByRole("option", { name: /Blender @blender .* CLI/i });
+    fireEvent.mouseDown(cliOption);
+
+    expect(screen.getAllByTestId("composer-cli-mention-blender")).toHaveLength(2);
+    expect(screen.queryByTestId("composer-handle-mention-blender")).not.toBeInTheDocument();
+    fireEvent.keyDown(input, { key: "Enter" });
+    fireEvent.keyDown(input, { key: "Enter" });
+
+    expect(onSend).toHaveBeenCalledWith("@blender then @blender", undefined, {
+      cliApps: [expect.objectContaining({ name: "blender" })],
+      continueActiveTurn: true,
+    });
+  });
+
+  it("does not reinterpret a disappeared handle as a same-name CLI app", () => {
+    const onSend = vi.fn();
+    const handle = session("blender-handle", "Session title", "", "blender");
+    const { rerender } = render(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        cliApps={CLI_APPS}
+        handleSessions={[handle]}
+      />,
+    );
+
+    const input = screen.getByRole("combobox", { name: "Message input" });
+    fireEvent.change(input, { target: { value: "@blend", selectionStart: 6 } });
+    fireEvent.keyDown(input, { key: "Tab" });
+    expect(screen.getByTestId("composer-handle-mention-blender")).toBeInTheDocument();
+
+    rerender(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        cliApps={CLI_APPS}
+        handleSessions={[]}
+      />,
+    );
+
+    expect(screen.queryByTestId("composer-handle-mention-blender")).not.toBeInTheDocument();
+    expect(screen.queryByTestId("composer-cli-mention-blender")).not.toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
+    expect(onSend).toHaveBeenCalledWith("@blender", undefined, undefined);
+  });
+
+  it("supports a prototype-named MCP through live and queued mention parsing", () => {
+    const onSend = vi.fn();
+    const constructorPreset: McpPresetInfo = {
+      ...MCP_PRESETS[0],
+      name: "constructor",
+      display_name: "Constructor",
+    };
+    render(
+      <ThreadComposer
+        onSend={onSend}
+        onStop={vi.fn()}
+        isStreaming
+        placeholder="Type your message..."
+        mcpPresets={[constructorPreset]}
+      />,
+    );
+
+    const input = screen.getByRole("combobox", { name: "Message input" });
+    fireEvent.change(input, {
+      target: { value: "use @constructor", selectionStart: 16 },
+    });
+    expect(screen.getByTestId("composer-mcp-mention-constructor")).toBeInTheDocument();
+
+    fireEvent.keyDown(input, { key: "Enter" });
+    fireEvent.keyDown(input, { key: "Enter" });
+    expect(screen.getByText("use @constructor")).toBeInTheDocument();
+    fireEvent.keyDown(input, { key: "Enter" });
+    expect(onSend).toHaveBeenCalledWith("use @constructor", undefined, {
+      mcpPresets: [expect.objectContaining({ name: "constructor" })],
+      continueActiveTurn: true,
+    });
  });

  it("releases the eight-session limit when a mention is removed", () => {
@@ -1878,11 +2196,21 @@ describe("ThreadComposer", () => {

    const input = screen.getByLabelText("Message input") as HTMLTextAreaElement;
    for (let index = 0; index < 8; index += 1) {
-      const value = `${input.value}${input.value ? " " : ""}@Topic${index}`;
+      const value = `${input.value}${input.value ? " " : ""}#Topic${index}`;
+      input.setSelectionRange(input.value.length, input.value.length);
+      fireEvent.select(input);
      fireEvent.change(input, { target: { value, selectionStart: value.length } });
      fireEvent.keyDown(input, { key: "Tab" });
    }
-    const replacement = `${input.value.replace("@Topic0 ", "")} @Topic8`;
+    const withoutFirst = input.value.replace("#Topic0 ", "");
+    input.setSelectionRange(0, "#Topic0 ".length);
+    fireEvent.select(input);
+    fireEvent.change(input, {
+      target: { value: withoutFirst, selectionStart: 0 },
+    });
+    const replacement = `${withoutFirst}#Topic8`;
+    input.setSelectionRange(withoutFirst.length, withoutFirst.length);
+    fireEvent.select(input);
    fireEvent.change(input, {
      target: { value: replacement, selectionStart: replacement.length },
    });
@@ -1896,7 +2224,7 @@ describe("ThreadComposer", () => {
    ))).toEqual(expect.arrayContaining(["websocket:topic-8"]));
  });

-  it("keeps a selected session stable across refreshes and queued guidance", () => {
+  it("keeps a selected handle mention when queuing guidance for the active turn", () => {
    const onSend = vi.fn();
    const target = session("z-target", "Plan", "Original plan");
    const { rerender } = render(
@@ -1905,7 +2233,7 @@ describe("ThreadComposer", () => {
        onStop={vi.fn()}
        isStreaming
        placeholder="Type your message..."
-        sessions={[target]}
+        handleSessions={[target]}
      />,
    );

@@ -1919,22 +2247,26 @@ describe("ThreadComposer", () => {
        onStop={vi.fn()}
        isStreaming
        placeholder="Type your message..."
-        sessions={[
+        handleSessions={[
          { ...target, title: "Renamed plan" },
-          session("a-new", "Plan", target.preview),
+          session("a-new", "Another title", target.preview, "Other"),
        ]}
      />,
    );

-    expect(screen.getByTestId("composer-session-mention-Plan")).toHaveTextContent("@Plan");
+    expect(screen.getByTestId("composer-handle-mention-Plan")).toHaveTextContent("@Plan");
+    fireEvent.keyDown(input, { key: "Enter" });
+    expect(
+      within(screen.getByRole("group", { name: "Queued guidance" })).getByText("@Plan"),
+    ).toBeInTheDocument();
    fireEvent.keyDown(input, { key: "Enter" });
-    fireEvent.click(screen.getByRole("button", { name: "Guide" }));

    expect(onSend).toHaveBeenCalledWith("@Plan", undefined, {
-      sessionMentions: [{
+      sessionHandles: [{
+        id: "handle_z-target",
        name: "Plan",
        session_key: "websocket:z-target",
-        title: "Plan",
+        color_slot: 2,
      }],
      continueActiveTurn: true,
    });
@@ -1993,6 +2325,49 @@ describe("ThreadComposer", () => {
    expect(input).toHaveValue(`please use $${skillName} `);
  });

+  it("keeps a later session occurrence bound while completing an earlier skill", () => {
+    const onSend = vi.fn();
+    const skillName = "arxiv-intelligence-filter";
+    render(
+      <ThreadComposer
+        onSend={onSend}
+        placeholder="Type your message..."
+        sessions={[session("plan", "Plan")]}
+        skills={[{
+          name: skillName,
+          description: "Research papers",
+          source: "builtin",
+          enabled: true,
+          available: true,
+        }]}
+      />,
+    );
+
+    const input = screen.getByLabelText("Message input") as HTMLTextAreaElement;
+    fireEvent.change(input, { target: { value: "#Pla", selectionStart: 4 } });
+    fireEvent.keyDown(input, { key: "Tab" });
+    expect(screen.getByTestId("composer-session-reference-Plan")).toBeInTheDocument();
+
+    input.setSelectionRange(0, 0);
+    fireEvent.select(input);
+    const withSkillQuery = `$arx ${input.value}`;
+    fireEvent.change(input, {
+      target: { value: withSkillQuery, selectionStart: 4, selectionEnd: 4 },
+    });
+    fireEvent.keyDown(input, { key: "Tab" });
+
+    expect(input).toHaveValue(`$${skillName} #Plan `);
+    expect(screen.getByTestId("composer-session-reference-Plan")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
+    expect(onSend).toHaveBeenCalledWith(`$${skillName} #Plan`, undefined, {
+      sessionMentions: [{
+        name: "Plan",
+        session_key: "websocket:plan",
+        title: "Plan",
+      }],
+    });
+  });
+
  it("ranks skill name matches ahead of earlier description matches", () => {
    render(
      <ThreadComposer
@@ -3043,6 +3418,38 @@ describe("ThreadComposer", () => {
    });
  });

+  it("migrates queued guidance from the v1 storage key without losing the prompt", async () => {
+    const legacyKey = "nanobot.webui.composerQueuedGuidance.v1:chat-a";
+    const currentKey = "nanobot.webui.composerQueuedGuidance.v2:chat-a";
+    window.localStorage.setItem(legacyKey, JSON.stringify([{
+      id: "legacy-guidance",
+      text: "keep this older queued prompt",
+      sessionMentions: [{
+        name: "old-handle",
+        session_key: "websocket:old-handle",
+        title: "Old handle",
+      }],
+    }]));
+
+    render(
+      <ThreadComposer
+        onSend={vi.fn()}
+        onStop={vi.fn()}
+        isStreaming
+        pendingQueueKey="chat-a"
+        placeholder="Type your message..."
+      />,
+    );
+
+    expect(await screen.findByText("keep this older queued prompt")).toBeInTheDocument();
+    expect(window.localStorage.getItem(legacyKey)).toBeNull();
+    expect(JSON.parse(window.localStorage.getItem(currentKey) ?? "[]"))
+      .toEqual([expect.objectContaining({
+        id: "legacy-guidance",
+        text: "keep this older queued prompt",
+      })]);
+  });
+
  it("keeps temporary chat guidance in memory only", async () => {
    const onSend = vi.fn();
    const view = render(
@@ -3062,7 +3469,7 @@ describe("ThreadComposer", () => {
    expect(await screen.findByText("do not persist this")).toBeInTheDocument();
    expect(
      window.localStorage.getItem(
-        "nanobot.webui.composerQueuedGuidance.v1:temporary-private",
+        "nanobot.webui.composerQueuedGuidance.v2:temporary-private",
      ),
    ).toBeNull();

@@ -3082,7 +3489,7 @@ describe("ThreadComposer", () => {
    });
    expect(
      window.localStorage.getItem(
-        "nanobot.webui.composerQueuedGuidance.v1:temporary-private",
+        "nanobot.webui.composerQueuedGuidance.v2:temporary-private",
      ),
    ).toBeNull();
  });
@@ -21,6 +21,7 @@ function makeClient() {
    (modelName: string | null, modelPreset?: string | null) => void
  >();
  const sessionUpdateHandlers = new Set<(chatId: string, scope?: string) => void>();
+  const runStatusHandlers = new Set<(chatId: string, startedAt: number | null) => void>();
  const runStartedAtByChatId = new Map<string, number>();
  const runGenerationByChatId = new Map<string, number>();
  const latestRunTurnIdByChatId = new Map<string, string>();
@@ -108,6 +109,13 @@ function makeClient() {
    },
    getRunStartedAt: (chatId: string) => runStartedAtByChatId.get(chatId) ?? null,
    getRunTurnId: (chatId: string) => latestRunTurnIdByChatId.get(chatId) ?? null,
+    onRunStatus: (handler: (chatId: string, startedAt: number | null) => void) => {
+      runStatusHandlers.add(handler);
+      for (const [chatId, startedAt] of runStartedAtByChatId) handler(chatId, startedAt);
+      return () => {
+        runStatusHandlers.delete(handler);
+      };
+    },
    finishRunLocally: vi.fn((chatId: string) => {
      runStartedAtByChatId.delete(chatId);
      latestRunTurnIdByChatId.delete(chatId);
@@ -417,6 +425,164 @@ describe("ThreadShell", () => {
    );
  });

+  it("keeps the current handle handle visible in the thread header", async () => {
+    const client = makeClient();
+    const currentSession = {
+      ...session("handle-handle"),
+      handle: {
+        id: "handle-current",
+        name: "mira",
+        session_key: "websocket:handle-handle",
+        color_slot: 3,
+      },
+    };
+
+    render(wrap(
+      client,
+      <ThreadShell
+        session={currentSession}
+        title="A title that may change independently"
+        onToggleSidebar={() => {}}
+      />,
+    ));
+
+    const handle = await screen.findByTestId("thread-handle-handle");
+    expect(handle).toHaveTextContent("@mira");
+    expect(handle.querySelector("[aria-hidden]")).toBeNull();
+    const headerDecoration = handle.querySelector("span[style*='border-bottom-color']");
+    expect(headerDecoration?.getAttribute("style"))
+      .toContain("var(--session-handle-3)");
+    expect(headerDecoration?.querySelector(".text-foreground"))
+      .toHaveClass("text-foreground");
+  });
+
+  it("pins each handle identity inside its workbench pane", async () => {
+    const client = makeClient();
+    const currentSession = {
+      ...session("pane-handle"),
+      handle: {
+        id: "handle-pane",
+        name: "kai",
+        session_key: "websocket:pane-handle",
+        color_slot: 2,
+      },
+    };
+
+    render(wrap(
+      client,
+      <ThreadShell
+        session={currentSession}
+        title="Investigate incoming messages"
+        onToggleSidebar={() => {}}
+        hideHeaderTitle
+        headerActive={false}
+      />,
+    ));
+
+    expect(screen.queryByTestId("thread-handle-handle")).not.toBeInTheDocument();
+    const identity = await screen.findByTestId("pane-handle-identity");
+    expect(identity).toHaveAttribute("data-active", "false");
+    expect(identity).toHaveAttribute("aria-label", "Session @kai");
+    expect(identity.querySelector("[data-pane-handle-handle]")).toHaveTextContent("@kai");
+    expect(identity.querySelector("[aria-hidden]")).toBeNull();
+    const paneDecoration = identity.querySelector(
+      "[data-pane-handle-handle] span[style*='border-bottom-color']",
+    );
+    expect(paneDecoration?.getAttribute("style")).toContain("var(--session-handle-2)");
+    const paneText = paneDecoration?.querySelector(".text-foreground");
+    expect(paneText).toHaveClass("text-foreground");
+    expect(paneText).not.toHaveClass("opacity-80");
+    expect(identity).not.toHaveTextContent("Investigate incoming messages");
+    expect(identity.className).not.toContain("bg-");
+    expect(identity.className).not.toContain("border-");
+  });
+
+  it("sends a structured handle mention through the focused thread", async () => {
+    const client = makeClient();
+    const source = {
+      ...session("source"),
+      handle: {
+        id: "handle_00000000000000000000000000000001",
+        name: "source",
+        session_key: "websocket:source",
+        color_slot: 1,
+      },
+    };
+    const reviewer = {
+      ...session("reviewer"),
+      handle: {
+        id: "handle_00000000000000000000000000000002",
+        name: "reviewer",
+        session_key: "websocket:reviewer",
+        color_slot: 2,
+      },
+    };
+    render(wrap(
+      client,
+      <ThreadShell
+        session={source}
+        sessions={[source, reviewer]}
+        title="Source"
+        onToggleSidebar={() => {}}
+      />,
+    ));
+
+    const input = await screen.findByLabelText("Message input") as HTMLTextAreaElement;
+    fireEvent.change(input, { target: { value: "@rev", selectionStart: 4 } });
+    fireEvent.keyDown(input, { key: "Tab" });
+    const message = `${input.value}check this`;
+    fireEvent.change(input, { target: { value: message, selectionStart: message.length } });
+    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
+
+    expect(client.sendMessage).toHaveBeenCalledWith(
+      source.chatId,
+      message,
+      undefined,
+      expect.objectContaining({
+        sessionHandles: [reviewer.handle],
+        turnId: expect.any(String),
+      }),
+    );
+  });
+
+  it("offers the focused session's own handle handle as a structured mention", async () => {
+    const client = makeClient();
+    const source = {
+      ...session("source-self"),
+      handle: {
+        id: "handle_00000000000000000000000000000003",
+        name: "bea",
+        session_key: "websocket:source-self",
+        color_slot: 3,
+      },
+    };
+
+    render(wrap(
+      client,
+      <ThreadShell
+        session={source}
+        sessions={[source]}
+        title="Source"
+        onToggleSidebar={() => {}}
+      />,
+    ));
+
+    const input = await screen.findByLabelText("Message input") as HTMLTextAreaElement;
+    fireEvent.change(input, { target: { value: "@be", selectionStart: 3 } });
+    fireEvent.keyDown(input, { key: "Tab" });
+    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
+
+    expect(client.sendMessage).toHaveBeenCalledWith(
+      source.chatId,
+      "@bea",
+      undefined,
+      expect.objectContaining({
+        sessionHandles: [source.handle],
+        turnId: expect.any(String),
+      }),
+    );
+  });
+
  it("keeps inferred file paths non-interactive when the availability probe fails", async () => {
    await preloadMarkdownText();
    const client = makeClient();
@@ -787,7 +953,7 @@ describe("ThreadShell", () => {
    fireEvent.click(badge);
    expect(onOpenModelSettings).toHaveBeenCalledTimes(1);

-    fireEvent.change(screen.getByRole("textbox", { name: "Message input" }), {
+    fireEvent.change(screen.getByRole("combobox", { name: "Message input" }), {
      target: { value: "hello" },
    });
    fireEvent.click(screen.getByRole("button", { name: "Configure model" }));
@@ -943,6 +1109,39 @@ describe("ThreadShell", () => {
    });
  });

+  it("does not offer persisted sessions inside a temporary chat", async () => {
+    const client = makeClient();
+    const handle = {
+      ...session("handle"),
+      title: "Reviewer",
+      handle: {
+        id: "handle_11111111111111111111111111111111",
+        name: "reviewer",
+        color_slot: 3,
+        session_key: "websocket:handle",
+      },
+    };
+    render(wrap(
+      client,
+      <ThreadShell
+        session={session("temporary")}
+        sessions={[handle]}
+        title="Temporary chat"
+        temporary
+        temporaryChatIds={["temporary"]}
+        onToggleSidebar={() => {}}
+      />,
+    ));
+
+    const input = await screen.findByLabelText("Message input");
+    await act(async () => {
+      fireEvent.change(input, { target: { value: "@", selectionStart: 1 } });
+    });
+
+    expect(screen.queryByRole("group", { name: "Nanobot conversations" }))
+      .not.toBeInTheDocument();
+  });
+
  it("highlights sent skill references without skill metadata", async () => {
    const client = makeClient();
    render(wrap(
@@ -2052,7 +2251,7 @@ describe("ThreadShell", () => {
    );

    await waitFor(() => expect(historyCalls).toBe(1));
-    const input = screen.getByRole("textbox", { name: "Message input" });
+    const input = screen.getByRole("combobox", { name: "Message input" });
    fireEvent.change(input, { target: { value: "rejected local turn" } });
    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
    await waitFor(() => expect(screen.getByText("rejected local turn")).toBeInTheDocument());
@@ -2289,7 +2488,7 @@ describe("ThreadShell", () => {
    act(() => client._emitSessionUpdate("chat-version-a"));
    await waitFor(() => expect(chatACalls).toBe(2));

-    fireEvent.change(screen.getByRole("textbox", { name: "Message input" }), {
+    fireEvent.change(screen.getByRole("combobox", { name: "Message input" }), {
      target: { value: "new question" },
    });
    fireEvent.click(screen.getByRole("button", { name: "Send message" }));
@@ -2390,7 +2589,7 @@ describe("ThreadShell", () => {
        turn_id: newTurnId,
      });
    });
-    const input = screen.getByRole("textbox", { name: "Message input" });
+    const input = screen.getByRole("combobox", { name: "Message input" });
    fireEvent.change(input, { target: { value: "queued for the new run" } });
    fireEvent.keyDown(input, { key: "Enter" });
    expect(client.sendMessage).not.toHaveBeenCalled();
@@ -2689,7 +2888,7 @@ describe("ThreadShell", () => {
        turn_id: turnId,
      });
    });
-    const input = screen.getByRole("textbox", { name: "Message input" });
+    const input = screen.getByRole("combobox", { name: "Message input" });
    fireEvent.change(input, { target: { value: "queued guidance" } });
    fireEvent.keyDown(input, { key: "Enter" });
    expect(client.sendMessage).not.toHaveBeenCalled();
@@ -2792,7 +2991,7 @@ describe("ThreadShell", () => {
      });
    });
    await waitFor(() => expect(screen.getByText("partial answer")).toBeInTheDocument());
-    const input = screen.getByRole("textbox", { name: "Message input" });
+    const input = screen.getByRole("combobox", { name: "Message input" });
    fireEvent.change(input, { target: { value: "queued guidance" } });
    fireEvent.keyDown(input, { key: "Enter" });
    expect(screen.getByText("queued guidance")).toBeInTheDocument();
@@ -2888,7 +3087,7 @@ describe("ThreadShell", () => {
    });

    await waitFor(() => expect(screen.getByText("Continuing the search.")).toBeInTheDocument());
-    const input = screen.getByRole("textbox", { name: "Message input" });
+    const input = screen.getByRole("combobox", { name: "Message input" });
    fireEvent.change(input, { target: { value: "How is it going?" } });
    fireEvent.keyDown(input, { key: "Enter" });
    fireEvent.keyDown(input, { key: "Enter" });
@@ -3930,41 +4129,56 @@ describe("ThreadShell", () => {
    );
  });

-  it("offers only same-project sessions in restricted mode", async () => {
-    const client = makeClient();
-    const currentScope = {
-      project_path: "/projects/current",
-      access_mode: "restricted" as const,
-    };
-    const sameProject = {
-      ...session("same-project"),
-      title: "Same project",
-      workspaceScope: currentScope,
-    };
-    const otherProject = {
-      ...session("other-project"),
-      title: "Other project",
-      workspaceScope: {
-        project_path: "/projects/other",
-        access_mode: "restricted" as const,
-      },
-    };
+  it.each(["restricted", "full"] as const)(
+    "offers routable sessions across projects in %s mode",
+    async (accessMode) => {
+      const client = makeClient();
+      const currentScope = {
+        project_path: "/projects/current",
+        access_mode: accessMode,
+      };
+      const sameProject = {
+        ...session("same-project"),
+        title: "Same project",
+        workspaceScope: currentScope,
+        handle: {
+          id: "handle_same_project",
+          name: "same-project",
+          color_slot: 1,
+          session_key: "websocket:same-project",
+        },
+      };
+      const otherProject = {
+        ...session("other-project"),
+        title: "Other project",
+        workspaceScope: {
+          project_path: "/projects/other",
+          access_mode: accessMode,
+        },
+        handle: {
+          id: "handle_other_project",
+          name: "other-project",
+          color_slot: 2,
+          session_key: "websocket:other-project",
+        },
+      };

-    render(wrap(
-      client,
-      <ThreadShell
-        session={session("current")}
-        sessions={[sameProject, otherProject]}
-        title="Current"
-        onToggleSidebar={() => {}}
-        workspaceScope={currentScope}
-      />,
-    ));
+      render(wrap(
+        client,
+        <ThreadShell
+          session={session("current")}
+          sessions={[sameProject, otherProject]}
+          title="Current"
+          onToggleSidebar={() => {}}
+          workspaceScope={currentScope}
+        />,
+      ));

-    const input = await screen.findByLabelText("Message input");
-    fireEvent.change(input, { target: { value: "@", selectionStart: 1 } });
+      const input = await screen.findByLabelText("Message input");
+      fireEvent.change(input, { target: { value: "@", selectionStart: 1 } });

-    expect(screen.getByRole("option", { name: /Same project/i })).toBeInTheDocument();
-    expect(screen.queryByRole("option", { name: /Other project/i })).not.toBeInTheDocument();
-  });
+      expect(screen.getByRole("option", { name: /^@same-project$/i })).toBeInTheDocument();
+      expect(screen.getByRole("option", { name: /^@other-project$/i })).toBeInTheDocument();
+    },
+  );
 });
@@ -215,7 +215,7 @@ function ViewportWithPromptNavigator({ messages }: { messages: UIMessage[] }) {
 }

 describe("ThreadViewport", () => {
-  it("keeps reasoning disclosure anchored for pointer and keyboard toggles", () => {
+  it("keeps unmanaged reasoning disclosure anchored for pointer and keyboard toggles", () => {
    const takeUserControl = vi.spyOn(
      ThreadMotionCoordinator.prototype,
      "takeUserControl",
@@ -38,6 +38,8 @@ const SEMANTIC_MESSAGE_FIELDS = [
  "cliApps",
  "mcpPresets",
  "sessionMentions",
+  "sessionHandles",
+  "handle",
  "reasoning",
  "latencyMs",
  "source",
@@ -70,6 +72,7 @@ function fakeClient() {
  const handlers = new Map<string, Set<(ev: InboundEvent) => void>>();
  const statusHandlers = new Set<(status: ConnectionStatus) => void>();
  const errorHandlers = new Set<(error: StreamError) => void>();
+  const runStatusHandlers = new Set<(chatId: string, startedAt: number | null) => void>();
  const runStartedAtByChatId = new Map<string, number>();
  const unsettledRunByChatId = new Map<string, boolean>();
  const goalStateByChatId = new Map<string, GoalStateWsPayload>();
@@ -113,6 +116,13 @@ function fakeClient() {
        errorHandlers.add(handler);
        return () => errorHandlers.delete(handler);
      },
+      onRunStatus(handler: (chatId: string, startedAt: number | null) => void) {
+        runStatusHandlers.add(handler);
+        for (const [chatId, startedAt] of runStartedAtByChatId) {
+          handler(chatId, startedAt);
+        }
+        return () => runStatusHandlers.delete(handler);
+      },
      getRunStartedAt(chatId: string) {
        const v = runStartedAtByChatId.get(chatId);
        return v === undefined ? null : v;
@@ -154,6 +164,11 @@ function fakeClient() {
    emitError(error: StreamError) {
      errorHandlers.forEach((handler) => handler(error));
    },
+    emitRunStatus(chatId: string, startedAt: number | null) {
+      if (startedAt === null) runStartedAtByChatId.delete(chatId);
+      else runStartedAtByChatId.set(chatId, startedAt);
+      runStatusHandlers.forEach((handler) => handler(chatId, startedAt));
+    },
    setUnsettled(chatId: string, unsettled: boolean) {
      unsettledRunByChatId.set(chatId, unsettled);
    },
@@ -182,6 +197,101 @@ async function flushStreamFrame() {
 }

 describe("useNanobotStream", () => {
+  it("keeps a handle mention on the focused chat's optimistic and outbound turn", () => {
+    const fake = fakeClient();
+    const { result } = renderHook(
+      () => useNanobotStream("chat-source", EMPTY_MESSAGES),
+      { wrapper: wrap(fake.client) },
+    );
+    const reviewer = {
+      id: "handle_00000000000000000000000000000001",
+      name: "reviewer",
+      session_key: "websocket:chat-reviewer",
+      color_slot: 3,
+    };
+
+    act(() => {
+      result.current.send("@reviewer check this", undefined, {
+        sessionHandles: [reviewer],
+      });
+    });
+
+    expect(result.current.messages).toEqual([
+      expect.objectContaining({
+        role: "user",
+        content: "@reviewer check this",
+        deliveryStatus: "sending",
+        sessionHandles: [reviewer],
+      }),
+    ]);
+    expect(result.current.isStreaming).toBe(true);
+    expect(fake.client.sendMessage).toHaveBeenCalledWith(
+      "chat-source",
+      "@reviewer check this",
+      undefined,
+      expect.objectContaining({
+        sessionHandles: [reviewer],
+        turnId: expect.any(String),
+      }),
+    );
+  });
+
+  it("renders an incoming handle message before the target model responds", async () => {
+    const fake = fakeClient();
+    const { result } = renderHook(
+      () => useNanobotStream("chat-handle", EMPTY_MESSAGES),
+      { wrapper: wrap(fake.client) },
+    );
+    const sessionMessageEvent: InboundEvent = {
+      event: "session_message",
+      chat_id: "chat-handle",
+      text: "What did you change?",
+      created_at_ms: 1_234,
+      turn_id: "handle-turn-1",
+      turn_phase: "user",
+      session_message: {
+        direction: "incoming",
+        message_id: "handle-message-1",
+        session: {
+          id: "handle_11111111111111111111111111111111",
+          name: "kai",
+          session_key: "websocket:source",
+          color_slot: 2,
+        },
+      },
+    };
+
+    act(() => {
+      fake.emit("chat-handle", sessionMessageEvent);
+      fake.emit("chat-handle", sessionMessageEvent);
+    });
+
+    expect(result.current.messages).toHaveLength(1);
+    expect(result.current.messages[0]).toMatchObject({
+      id: "session-message:handle-message-1",
+      role: "user",
+      content: "What did you change?",
+      createdAt: 1_234,
+      turnId: "handle-turn-1",
+      turnPhase: "user",
+      sessionMessage: sessionMessageEvent.session_message,
+    });
+    expect(result.current.isStreaming).toBe(true);
+
+    act(() => fake.emit("chat-handle", {
+      event: "delta",
+      chat_id: "chat-handle",
+      text: "I changed",
+      turn_id: "handle-turn-1",
+    }));
+    await flushStreamFrame();
+
+    expect(result.current.messages.map((message) => message.role)).toEqual([
+      "user",
+      "assistant",
+    ]);
+  });
+
  it("batches answer deltas into one animation-frame update", async () => {
    const fake = fakeClient();
    const requestFrame = vi.spyOn(window, "requestAnimationFrame");
@@ -2865,6 +2975,28 @@ describe("useNanobotStream", () => {
    expect(result.current.isStreaming).toBe(false);
  });

+  it("clears the pane timer when canonical reconciliation settles the client run", () => {
+    const fake = fakeClient();
+    const { result } = renderHook(() => useNanobotStream("chat-g", EMPTY_MESSAGES), {
+      wrapper: wrap(fake.client),
+    });
+
+    act(() => {
+      fake.emit("chat-g", {
+        event: "goal_status",
+        chat_id: "chat-g",
+        status: "running",
+        started_at: 1700,
+        turn_id: "handle:turn-1",
+      });
+    });
+    expect(result.current.runStartedAt).toBe(1700);
+
+    act(() => fake.emitRunStatus("chat-g", null));
+
+    expect(result.current.runStartedAt).toBeNull();
+  });
+
  it("restores runStartedAt after switching away and back when goal_status was recorded without a subscriber", () => {
    const fake = fakeClient();
    const { result, rerender } = renderHook(