fix(ai): reconcile pending search matches with current sessions

application/i18n/locales/en/ai.ts

@@ -538,6 +538,7 @@ export const enAiMessages: Messages = {
   'ai.chat.searchSessions': 'Search titles and recent content…',
   'ai.chat.clearSessionSearch': 'Clear session search',
   'ai.chat.searchSessionsHint': 'Searches titles, prioritizing newer messages and entries. For long messages and tool outputs, only a limited portion at the beginning is searched. This is not full-text search.',
+  'ai.chat.searchingSessions': 'Searching...',
   'ai.chat.noMatchingSessions': 'No matches in titles or recent retained content',
   'ai.chat.noSessions': 'No previous sessions',
   'ai.chat.forkFromHere': 'Fork from here',

application/i18n/locales/es/ai.ts

@@ -529,6 +529,7 @@ export const esAiMessages: Messages = {
   'ai.chat.searchSessions': 'Buscar títulos y contenido reciente…',
   'ai.chat.clearSessionSearch': 'Borrar la búsqueda de sesiones',
   'ai.chat.searchSessionsHint': 'Busca en los títulos y da prioridad a los mensajes y entradas más recientes. De los mensajes largos y las salidas de herramientas, solo se busca una parte limitada del comienzo. No es una búsqueda de texto completo.',
+  'ai.chat.searchingSessions': 'Buscando...',
   'ai.chat.noMatchingSessions': 'Sin coincidencias en títulos ni contenido reciente conservado',
   'ai.chat.noSessions': 'No hay sesiones anteriores',
   'ai.chat.forkFromHere': 'Bifurcar desde aquí',

application/i18n/locales/ru/ai.ts

@@ -485,6 +485,7 @@ export const ruAiMessages: Messages = {
   'ai.chat.searchSessions': 'Поиск по заголовкам и недавнему содержимому…',
   'ai.chat.clearSessionSearch': 'Очистить поиск сессий',
   'ai.chat.searchSessionsHint': 'Поиск по заголовкам с приоритетом более новых сообщений и записей. В длинных сообщениях и результатах инструментов поиск охватывает только ограниченную начальную часть. Это не полнотекстовый поиск.',
+  'ai.chat.searchingSessions': 'Поиск...',
   'ai.chat.noMatchingSessions': 'Нет совпадений в заголовках и недавнем сохранённом содержимом',
   'ai.chat.noSessions': 'Предыдущих сессий нет',
   'ai.chat.forkFromHere': 'Ветвление отсюда',

application/i18n/locales/zh-CN/ai.ts

@@ -538,6 +538,7 @@ export const zhCNAiMessages: Messages = {
   'ai.chat.searchSessions': '搜索标题和近期内容…',
   'ai.chat.clearSessionSearch': '清空会话搜索',
   'ai.chat.searchSessionsHint': '搜索标题，并优先搜索较新的消息和条目；超长消息及工具输出仅搜索开头的有限部分。这不是全文搜索。',
+  'ai.chat.searchingSessions': '搜索中…',
   'ai.chat.noMatchingSessions': '标题和近期保留的内容中没有匹配结果',
   'ai.chat.noSessions': '没有历史会话',
   'ai.chat.forkFromHere': '从此处分叉',

application/i18n/locales/zh-TW/ai.ts

@@ -528,6 +528,7 @@ export const zhTWAiMessages: Messages = {
   'ai.chat.searchSessions': '搜尋標題和近期內容…',
   'ai.chat.clearSessionSearch': '清空會話搜尋',
   'ai.chat.searchSessionsHint': '搜尋標題，並優先搜尋較新的訊息與項目；超長訊息與工具輸出僅搜尋開頭的有限部分。這不是全文搜尋。',
+  'ai.chat.searchingSessions': '搜尋中…',
   'ai.chat.noMatchingSessions': '標題和近期保留的內容中沒有符合的結果',
   'ai.chat.noSessions': '沒有歷史工作階段',
   'ai.chat.forkFromHere': '從此處分叉',

application/state/sessionHistorySearch.test.ts

@@ -788,3 +788,44 @@ test("history alone bounds title pinyin while retaining literal title and body m
   assert.deepEqual(filterSessionHistory(sessions, "fuwuqi nginx"), [sessions[0]]);
   assert.deepEqual(filterSessionHistory(sessions, "服务器 nginx"), sessions);
 });
+
+test("cooperative search yields and preserves the synchronous matching and order", () => {
+  const search = createSessionHistorySearch();
+  const sessions = Array.from({ length: 90 }, (_, index) => createSession(
+    String(index), `Session ${index}`, [{ content: index % 7 === 0 ? "needle 中文" : "ordinary body" }],
+  ));
+  const expected = search.filterSessionHistory(sessions, "needle");
+  const scan = search.createScan<typeof sessions[number]>("needle");
+  assert.equal(scan.step(sessions), null, "a large cached search still yields between slices");
+  let result: typeof sessions | null = null;
+  for (let step = 0; step < 20 && result === null; step += 1) result = scan.step(sessions);
+  assert.deepEqual(result, expected);
+  scan.dispose();
+  assert.equal(scan.step(sessions), null);
+});
+
+test("cooperative search incorporates live replacements and removals without restarting stable work", () => {
+  let reads = 0;
+  const stable = Array.from({ length: 90 }, (_, index) => {
+    const session = createSession(String(index), `Session ${index}`, []);
+    session.messages = [{ get content() { reads += 1; return index % 7 === 0 ? "needle" : "ordinary"; } }];
+    return session;
+  });
+  const search = createSessionHistorySearch();
+  const scan = search.createScan<typeof stable[number]>("needle");
+  let result: typeof stable | null = null;
+  let sessions = stable;
+  let steps = 0;
+  while (result === null && steps < 30) {
+    // The newest session changes on every slice, like an active stream.
+    const streaming = createSession("streaming", `Streaming ${steps}`, [{ content: "needle" }]);
+    sessions = [streaming, ...stable.slice(0, -1).reverse()];
+    result = scan.step(sessions);
+    steps += 1;
+  }
+  assert.ok(result, "a live stream cannot starve the other sessions");
+  assert.ok(steps < 10, `stable work restarted (${steps} slices)`);
+  assert.deepEqual(result, sessions.filter((session) => session.id === "streaming" || Number(session.id) % 7 === 0));
+  assert.equal(reads, 89, "each retained stable session is indexed only once");
+  scan.dispose();
+});

application/state/sessionHistorySearch.ts

@@ -349,6 +349,56 @@ function filterSessionHistoryStore<T extends SessionHistorySearchTarget>(
   }
 }
 
+/** One query retains only match decisions while its indexes stay memory-bounded. */
+export type SessionHistorySearchScan<T extends SessionHistorySearchTarget> = {
+  /** Null means more work remains; each call yields after a short bounded slice. */
+  step: (sessions: readonly T[]) => T[] | null;
+  dispose: () => void;
+};
+
+function createSessionHistorySearchScan<T extends SessionHistorySearchTarget>(
+  store: SessionHistorySearchStore,
+  query: string,
+  options: SessionHistorySearchOptions,
+): SessionHistorySearchScan<T> {
+  const preparedQuery = prepareSearchQuery(truncateQueryForMatch(query.trim()));
+  const matches = new Map<T, boolean>();
+  let disposed = false;
+  store.scanTouched.clear();
+  return {
+    step(sessions) {
+      if (disposed) return null;
+      const live = new Set<SessionHistorySearchTarget>(sessions);
+      for (const session of matches.keys()) {
+        if (!live.has(session)) matches.delete(session);
+      }
+      for (const session of store.scanTouched) {
+        if (!live.has(session)) store.scanTouched.delete(session);
+      }
+      pruneSessionSearchIndexCache(store, sessions);
+      const startedAt = performance.now();
+      let processed = 0;
+      for (const session of sessions) {
+        if (matches.has(session)) continue;
+        const index = getSessionSearchIndex(store, session, options.untitledLabel ?? '');
+        matches.set(session, matchesSessionSearchIndex(preparedQuery, index));
+        processed += 1;
+        // A session already has a bounded searchable corpus. Also cap the
+        // number per slice so a fast clock/cache cannot make a huge task.
+        if (processed >= 16 || performance.now() - startedAt >= 4) return null;
+      }
+      pruneSessionSearchIndexCache(store, sessions);
+      store.scanTouched.clear();
+      return sessions.filter((session) => matches.get(session));
+    },
+    dispose() {
+      disposed = true;
+      matches.clear();
+      store.scanTouched.clear();
+    },
+  };
+}
+
 /**
  * One stateful search instance per consumer (one mounted session history
  * drawer). The cache lives in the returned instance's store instead of module
@@ -362,6 +412,10 @@ export type SessionHistorySearch = {
     query: string,
     options?: SessionHistorySearchOptions,
   ) => T[];
+  createScan: <T extends SessionHistorySearchTarget>(
+    query: string,
+    options?: SessionHistorySearchOptions,
+  ) => SessionHistorySearchScan<T>;
   clearSessionHistorySearchCache: () => void;
 };
 
@@ -375,6 +429,9 @@ export function createSessionHistorySearch(): SessionHistorySearch {
     filterSessionHistory(sessions, query, options = {}) {
       return filterSessionHistoryStore(store, sessions, query, options);
     },
+    createScan(query, options = {}) {
+      return createSessionHistorySearchScan(store, query, options);
+    },
     clearSessionHistorySearchCache() {
       clearSessionHistorySearchStore(store);
     },

application/state/useSessionHistorySearch.ts

@@ -1,24 +1,93 @@
-import { useEffect, useMemo } from 'react';
+import { useEffect, useLayoutEffect, useMemo, useRef, useState } from 'react';
+import type { SessionHistorySearchTarget } from '../../domain/sessionHistorySearch';
 import {
   createSessionHistorySearch,
-  type SessionHistorySearch,
+  type SessionHistorySearchScan,
 } from './sessionHistorySearch';
 
-/**
- * Owns one search instance per mounted session history drawer.
- *
- * The search index cache is bound to this instance (not module scope), so
- * several concurrently mounted drawers — one per terminal tab — each keep
- * their own indexes: pruning in one drawer never drops another drawer's
- * entries, and the unmount below releases only this drawer's store instead of
- * discarding the shared cache for every drawer. Cache keys are the session
- * objects themselves, so clearing on unmount drops all strong session
- * references together with the retained haystack characters.
- */
-export function useSessionHistorySearch(): SessionHistorySearch {
+/** Search outside rendering, yielding between bounded slices for input/paint. */
+export function useSessionHistorySearch<T extends SessionHistorySearchTarget>(
+  sessions: readonly T[],
+  query: string,
+  untitledLabel: string,
+): { filteredSessions: readonly T[]; isSearching: boolean } {
   const search = useMemo(() => createSessionHistorySearch(), []);
+  const latest = useRef({ sessions, query, untitledLabel });
+  const work = useRef<{
+    query: string;
+    untitledLabel: string;
+    scan: SessionHistorySearchScan<T>;
+  } | null>(null);
+  const timer = useRef<ReturnType<typeof setTimeout> | null>(null);
+  const [result, setResult] = useState<{
+    sessions: readonly T[];
+    query: string;
+    untitledLabel: string;
+    filteredSessions: T[];
+  } | null>(null);
+
+  useLayoutEffect(() => {
+    latest.current = { sessions, query, untitledLabel };
+  }, [sessions, query, untitledLabel]);
+
+  useEffect(() => {
+    const cancel = () => {
+      if (timer.current !== null) clearTimeout(timer.current);
+      timer.current = null;
+      work.current?.scan.dispose();
+      work.current = null;
+    };
+    if (!query.trim()) {
+      cancel();
+      setResult(null);
+      // Release deleted/replaced sessions without indexing any message bodies.
+      search.filterSessionHistory(sessions, '');
+      return;
+    }
+    if (work.current?.query !== query || work.current.untitledLabel !== untitledLabel) {
+      cancel();
+      work.current = { query, untitledLabel, scan: search.createScan<T>(query, { untitledLabel }) };
+    }
+    if (timer.current !== null) return;
+    const job = work.current;
+    const run = () => {
+      timer.current = null;
+      const current = latest.current;
+      if (work.current !== job || current.query !== job.query || current.untitledLabel !== job.untitledLabel) return;
+      const filteredSessions = job.scan.step(current.sessions);
+      if (filteredSessions === null) {
+        timer.current = setTimeout(run, 0);
+      } else {
+        setResult({ ...current, filteredSessions });
+      }
+    };
+    // Even the first slice runs after the input's render/commit has returned.
+    // Session updates reuse the in-flight query's match decisions, so one
+    // streaming session cannot restart and starve a large history search.
+    timer.current = setTimeout(run, 0);
+  }, [sessions, query, untitledLabel, search]);
+
   useEffect(() => () => {
+    if (timer.current !== null) clearTimeout(timer.current);
+    timer.current = null;
+    work.current?.scan.dispose();
+    work.current = null;
     search.clearSessionHistorySearchCache();
   }, [search]);
-  return search;
+
+  const filteredSessions = useMemo(() => {
+    if (!query.trim()) return sessions;
+    if (result?.query !== query || result.untitledLabel !== untitledLabel) return [];
+    if (result.sessions === sessions) return result.filteredSessions;
+    // Keep only confirmed, unchanged objects in the current order while the
+    // scheduled scan checks new/replaced sessions. Do not read message bodies
+    // here, or make the whole list disappear on each streaming update.
+    const confirmed = new Set(result.filteredSessions);
+    return sessions.filter((session) => confirmed.has(session));
+  }, [sessions, query, untitledLabel, result]);
+  const sameQuery = result?.query === query && result.untitledLabel === untitledLabel;
+  return {
+    filteredSessions,
+    isSearching: Boolean(query.trim()) && (!sameQuery || result.sessions !== sessions),
+  };
 }

components/AIChatSessionHistoryDrawer.responsiveness.test.tsx

@@ -0,0 +1,137 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import React from "react";
+
+import type { AISession } from "../infrastructure/ai/types.ts";
+import { createDomRenderer, dispatchDomEvent, installDomEnvironment, runWithAct } from "./test-support/renderReactDom.tsx";
+
+test("history input yields before indexing long sessions and never publishes an obsolete query", async (t) => {
+  const env = installDomEnvironment();
+  const { SessionHistoryDrawer } = await import("./AIChatSessionHistoryDrawer.tsx");
+  const { I18nProvider } = await import("../application/i18n/I18nProvider.tsx");
+  const { TooltipProvider } = await import("./ui/tooltip.tsx");
+  const renderer = await createDomRenderer(env.document);
+  t.after(async () => { await renderer.unmount(); env.cleanup(); });
+
+  let heartbeat = false;
+  let readsBeforeHeartbeat = 0;
+  let reads = 0;
+  const body = "representative retained output and ordinary content ".repeat(400);
+  let sessions: AISession[] = Array.from({ length: 180 }, (_, index) => ({
+    id: `session-${index}`,
+    title: `Session ${index}`,
+    agentId: "catty",
+    scope: { type: "terminal", targetId: "fixture" },
+    createdAt: 0,
+    updatedAt: 0,
+    messages: Array.from({ length: 4 }, (_, part) => ({
+      id: `message-${index}-${part}`,
+      role: "assistant" as const,
+      timestamp: 0,
+      get content() {
+        reads += 1;
+        if (!heartbeat) readsBeforeHeartbeat += 1;
+        return index === 179 && part === 3 ? "latest-match" : body;
+      },
+    })),
+  }));
+  const noop = () => {};
+  const render = () => renderer.render(
+    <I18nProvider locale="en"><TooltipProvider>
+      <SessionHistoryDrawer sessions={sessions} activeSessionId={null} onSelect={noop} onDelete={noop} onClose={noop} />
+    </TooltipProvider></I18nProvider>,
+  );
+  const query = async (value: string) => {
+    const input = renderer.container.querySelector("input")!;
+    Object.getOwnPropertyDescriptor(env.window.HTMLInputElement.prototype, "value")!.set!.call(input, value);
+    await dispatchDomEvent(input, new env.window.Event("input", { bubbles: true }));
+    assert.equal(input.value, value);
+  };
+  const waitFor = async (condition: () => boolean) => {
+    for (let attempt = 0; attempt < 300 && !condition(); attempt += 1) {
+      await runWithAct(() => new Promise((resolve) => setTimeout(resolve, 5)));
+    }
+    assert.ok(condition(), "search did not settle");
+  };
+
+  await render();
+  assert.equal(reads, 0, "blank query never indexes message bodies");
+  setTimeout(() => { heartbeat = true; }, 0);
+  await query("never-match");
+  assert.equal(readsBeforeHeartbeat, 0, "typing must return to the event loop before indexing messages");
+  await query("latest-match");
+  await waitFor(() => renderer.container.querySelectorAll('[role="button"]').length === 1);
+  assert.match(renderer.container.querySelector('[role="button"]')!.textContent!, /Session 179/);
+
+  // A streaming session changes while a large search is running. Keep progress
+  // on unchanged sessions, search the replacement, and respect the new order.
+  await query("new-live-match");
+  sessions = [{ ...sessions[10], title: "New live match", messages: [{ id: "replacement", role: "assistant", content: "new-live-match", timestamp: 1 }] }, ...sessions.filter((session) => session.id !== "session-10" && session.id !== "session-179")];
+  await render();
+  await waitFor(() => renderer.container.querySelector('[role="button"]')?.textContent?.includes("New live match") === true);
+  assert.equal(renderer.container.querySelectorAll('[role="button"]').length, 1);
+  await query("");
+  assert.equal(renderer.container.querySelectorAll('[role="button"]').length, 80);
+});
+
+test("pending history updates immediately remove stale matches and retain current ordering", async (t) => {
+  const env = installDomEnvironment();
+  const { SessionHistoryDrawer } = await import("./AIChatSessionHistoryDrawer.tsx");
+  const { I18nProvider } = await import("../application/i18n/I18nProvider.tsx");
+  const { TooltipProvider } = await import("./ui/tooltip.tsx");
+  const renderer = await createDomRenderer(env.document);
+  t.after(async () => { await renderer.unmount(); env.cleanup(); });
+  const make = (id: string, matches: boolean): AISession => ({
+    id, title: id, agentId: "catty", scope: { type: "terminal", targetId: "fixture" },
+    createdAt: 0, updatedAt: 0,
+    messages: [{ id: `${id}-message`, role: "assistant", content: matches ? "needle" : "ordinary", timestamp: 0 }],
+  });
+  const a = make("Match A", true);
+  const b = make("Match B", true);
+  const c = make("Match C", true);
+  const rest = Array.from({ length: 100 }, (_, index) => make(`Other ${index}`, false));
+  let sessions = [a, b, c, ...rest];
+  let revision = 0;
+  const commits: string[][] = [];
+  const rowLabels = () => [...renderer.container.querySelectorAll('[role="button"]')]
+    .map((row) => row.querySelector("span")?.textContent ?? "");
+  const noop = () => {};
+  const Frame = ({ items, version }: { items: AISession[]; version: number }) => {
+    React.useLayoutEffect(() => {
+      if (version > 0) commits.push(rowLabels());
+    }, [items, version]);
+    return <SessionHistoryDrawer sessions={items} activeSessionId={null} onSelect={noop} onDelete={noop} onClose={noop} />;
+  };
+  const render = () => renderer.render(<I18nProvider locale="en"><TooltipProvider>
+    <Frame items={sessions} version={revision} />
+  </TooltipProvider></I18nProvider>);
+  const settle = async (expected: string[]) => {
+    for (let attempt = 0; attempt < 200 && renderer.container.querySelector('[aria-busy="true"]'); attempt += 1) {
+      await runWithAct(() => new Promise((resolve) => setTimeout(resolve, 5)));
+    }
+    assert.deepEqual(rowLabels(), expected);
+  };
+  await render();
+  const input = renderer.container.querySelector("input")!;
+  Object.getOwnPropertyDescriptor(env.window.HTMLInputElement.prototype, "value")!.set!.call(input, "needle");
+  await dispatchDomEvent(input, new env.window.Event("input", { bubbles: true }));
+  await settle(["Match A", "Match B", "Match C"]);
+
+  revision += 1;
+  sessions = [c, a, b, ...rest];
+  await render();
+  assert.deepEqual(commits.at(-1), ["Match C", "Match A", "Match B"], "pending results follow the current list order in the very first commit");
+  await settle(["Match C", "Match A", "Match B"]);
+
+  revision += 1;
+  sessions = [c, make("Match A", false), ...rest];
+  await render();
+  assert.deepEqual(commits.at(-1), ["Match C"], "deleted and replaced objects cannot remain selectable; unchanged matches stay visible");
+  await settle(["Match C"]);
+
+  revision += 1;
+  sessions = [make("Match D", true), ...sessions];
+  await render();
+  assert.deepEqual(commits.at(-1), ["Match C"]);
+  await settle(["Match D", "Match C"]);
+});

components/AIChatSessionHistoryDrawer.test.tsx

@@ -4,7 +4,7 @@ import React from "react";
 
 import type { AISession } from "../infrastructure/ai/types.ts";
 import { MESSAGES_BY_LOCALE } from "../application/i18n/messages.ts";
-import { createDomRenderer, dispatchDomEvent, installDomEnvironment } from "./test-support/renderReactDom.tsx";
+import { createDomRenderer, dispatchDomEvent, installDomEnvironment, runWithAct } from "./test-support/renderReactDom.tsx";
 
 test("history drawer filters, pages, clears and explains the bounded search in every locale", async () => {
   const dom = installDomEnvironment();
@@ -51,6 +51,10 @@ test("history drawer filters, pages, clears and explains the bounded search in e
     const setValue = Object.getOwnPropertyDescriptor(dom.window.HTMLInputElement.prototype, "value")!.set!;
     setValue.call(input, query);
     await dispatchDomEvent(input, new dom.window.Event("input", { bubbles: true }));
+    for (let attempt = 0; attempt < 100 && renderer.container.querySelector('[aria-busy="true"]'); attempt += 1) {
+      await runWithAct(() => new Promise((resolve) => setTimeout(resolve, 5)));
+    }
+    assert.equal(renderer.container.querySelector('[aria-busy="true"]'), null, "search must settle");
   };
   const loadMore = () => [...renderer.container.querySelectorAll("button")]
     .find((button) => button.textContent?.includes("Load more"));

components/AIChatSessionHistoryDrawer.tsx

@@ -37,15 +37,10 @@ export const SessionHistoryDrawer: React.FC<SessionHistoryDrawerProps> = ({
   const [searchQuery, setSearchQuery] = useState('');
   const searchHintId = useId();
   const searchInputRef = useRef<HTMLInputElement>(null);
-  // One cache instance per mounted drawer: caches of concurrently mounted
-  // drawers stay independent (no shared state to prune or discard across tabs).
-  const search = useSessionHistorySearch();
-
-  const filteredSessions = React.useMemo(
-    // The localized fallback below is displayed for untitled sessions
-    // (row label), so it must be indexed for search as the displayed title.
-    () => search.filterSessionHistory(sessions, searchQuery, { untitledLabel: t('ai.chat.untitled') }),
-    [sessions, searchQuery, t, search],
+  const { filteredSessions, isSearching } = useSessionHistorySearch(
+    sessions,
+    searchQuery,
+    t('ai.chat.untitled'),
   );
 
   // Reset the render batch when the list scope or query changes so matching
@@ -103,7 +98,12 @@ export const SessionHistoryDrawer: React.FC<SessionHistoryDrawerProps> = ({
           {t('ai.chat.searchSessionsHint')}
         </p>
       </div>
-      <ScrollArea className="flex-1">
+      <ScrollArea className="flex-1" aria-busy={isSearching}>
+        {isSearching && (
+          <p role="status" className="px-4 py-2 text-[12px] text-muted-foreground/60">
+            {t('ai.chat.searchingSessions')}
+          </p>
+        )}
         <div className="px-3">
           {sessions.length === 0 ? (
             <div className="py-12 text-center">
@@ -111,7 +111,7 @@ export const SessionHistoryDrawer: React.FC<SessionHistoryDrawerProps> = ({
                 {t('ai.chat.noSessions')}
               </p>
             </div>
-          ) : filteredSessions.length === 0 ? (
+          ) : filteredSessions.length === 0 && !isSearching ? (
             <div className="py-12 text-center">
               <p className="text-[13px] text-muted-foreground/40">
                 {t('ai.chat.noMatchingSessions')}

docs/research/chat-history-search-performance.md

@@ -0,0 +1,63 @@
+# Chat history search responsiveness
+
+The search introduced in #3601 ran its entire bounded-content scan inside the
+history drawer render. The index cache limits retained memory, but histories
+larger than that cache still rebuilt older indexes on each keystroke. A changing
+streamed conversation also refreshed the session list and repeated that scan.
+
+Search now runs in scheduled slices of at most 16 sessions or approximately
+4 ms. The existing per-session text limits, matching rules, index-memory bounds
+and session order remain unchanged. A query change cancels the previous scan;
+streaming updates keep match decisions for unchanged sessions and recheck the
+replacement objects, so ongoing output cannot repeatedly restart the search.
+The drawer shows a searching status and clears obsolete-query results until the
+current query finishes. While the session list changes, only still-present,
+unchanged matched objects stay visible, in the current list order; removed or
+replaced objects cannot remain selectable until the next slice. Clearing the
+query restores the unfiltered history
+immediately and releases the search's previous results.
+
+## Verification
+
+A separate Electron window mounted the actual before/after history drawer with
+500 synthetic conversations, each containing about 64,000 retained characters.
+No user conversations, terminals or provider calls were used. The same input
+and ten updates to a single conversation produced:
+
+| Work | Before | After |
+| --- | ---: | ---: |
+| Input handler return | 352.7 ms | 4.0 ms |
+| Single conversation update | 319.4–323.3 ms | 1.49–1.90 ms |
+| Final results for the fixture query | 1 matching conversation | Same conversation |
+
+The old input/update tasks each blocked for over 300 ms; the repaired search
+produced no task of 50 ms or longer in this run. These are development-fixture
+measurements on one machine, not a guarantee for every device or history size.
+Native input, empty results and the matching conversation were also checked in
+the rendered window.
+
+The drawer regression drives the actual input event and verifies that a queued
+event-loop heartbeat runs before any retained message is indexed. It fails on
+the previous implementation (720 synchronous message reads) and passes after
+the repair. Further tests cover obsolete queries, live replacements/removals,
+continuous-stream progress, result order and the existing matching limits.
+
+```sh
+node --test --import tsx \
+  components/AIChatSessionHistoryDrawer.test.tsx \
+  components/AIChatSessionHistoryDrawer.responsiveness.test.tsx \
+  application/state/sessionHistorySearch.test.ts
+```
+
+## Pending-result freshness
+
+A follow-up review found that the first repair could temporarily show results
+from the previous session snapshot. A second Electron comparison used the
+initial repair (`a8b291b7c`) and the reconciled version. Removing or replacing the
+matching session left it selectable in the initial repair's first commit; the
+reconciled version immediately removed it. Reversing the current list initially
+kept session 0 first; it now immediately shows session 499 first. Unchanged
+confirmed matches remain visible while changed objects are checked, so a stream
+does not blank every result. This check compares object references and ordering
+without rereading retained message text. Input remained about 4 ms for the same
+500-conversation fixture.