diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 4b01b13f216..e25f6cffa85 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -880,6 +880,11 @@ jobs:
           src/relay/windows-port-scan.win32.test.ts
           src/main/ai-vault-search/session-search-fts5-contract.test.ts
           src/main/ai-vault-search/session-search-schema.test.ts
+          src/main/ai-vault-search/session-search-query-regressions.test.ts
+          src/main/ai-vault-search/session-search-retention-delete.test.ts
+          src/main/ai-vault-search/session-search-refresh-lane.test.ts
+          src/main/ai-vault/session-newest-files.test.ts
+          src/main/ai-vault/session-scanner-discovery-cancellation.test.ts
 
       # Why the :parallel variant: identical to build:release except the three
       # electron-vite targets overlap instead of running back to back. The Linux package
diff --git a/config/scripts/session-search-retention-benchmark.ts b/config/scripts/session-search-retention-benchmark.ts
new file mode 100644
index 00000000000..f180cdaa080
--- /dev/null
+++ b/config/scripts/session-search-retention-benchmark.ts
@@ -0,0 +1,88 @@
+import assert from 'node:assert/strict'
+import { mkdtemp, rm, stat } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { setImmediate as yieldToEventLoop } from 'node:timers/promises'
+import SyncDatabase from '../../src/main/sqlite/sync-database'
+import { SessionSearchStore } from '../../src/main/ai-vault-search/session-search-store'
+import { deleteExpiredSearchFiles } from '../../src/main/ai-vault-search/session-search-retention-delete'
+import { SessionSearchIndexWriter } from '../../src/main/ai-vault-search/session-search-index-writer'
+
+// Bundle with esbuild --bundle --platform=node, then run on the host under test.
+const root = await mkdtemp(join(tmpdir(), 'orca-search-retention-bench-'))
+try {
+  for (const mode of ['whole-file', 'batched', 'batched-pinned-reader']) {
+    const path = join(root, `${mode}.sqlite`)
+    const store = new SessionSearchStore(path)
+    let reader: SyncDatabase | null = null
+    try {
+      const db = store.db
+      db.exec(`INSERT INTO sessions(id,agent,session_id,file_path,title,cwd,cwd_key,resume_command)
+        VALUES (1,'claude','1','fixture','synthetic benchmark','/fixture','/fixture','');
+        INSERT INTO files(path,byte_offset,mtime_ms,session_row_id) VALUES ('fixture',1,1,1);
+        BEGIN;
+        WITH RECURSIVE n(i) AS (VALUES(1) UNION ALL SELECT i+1 FROM n WHERE i<60000)
+        INSERT INTO messages(id,session_row_id,role) SELECT i,1,'user' FROM n;
+        INSERT INTO messages_fts(rowid,user_text) SELECT id,'synthetic benchmark needle ' || id ||
+          ' repeated context for a representative coding conversation with commands and paths src/example.ts'
+          FROM messages;
+        INSERT INTO conversation_fts(rowid,user_text) SELECT rowid,user_text FROM messages_fts;
+        COMMIT; PRAGMA wal_checkpoint(TRUNCATE)`)
+      assert.equal(store.search({ query: 'needle' }).hits.length, 1)
+      if (mode === 'batched-pinned-reader') {
+        reader = new SyncDatabase(path, { readonly: true })
+        reader.exec('BEGIN')
+        reader.prepare('SELECT count(*) FROM messages').get()
+      }
+      const intervals: number[] = []
+      let previous = performance.now()
+      const started = previous
+      if (mode === 'whole-file') {
+        new SessionSearchIndexWriter(db).removeFile('fixture')
+        intervals.push(performance.now() - previous)
+      } else {
+        await deleteExpiredSearchFiles(
+          db,
+          100,
+          () => false,
+          () => {},
+          async () => {
+            intervals.push(performance.now() - previous)
+            assert.equal(store.search({ query: 'needle' }).hits.length, 0)
+            await yieldToEventLoop()
+            previous = performance.now()
+          }
+        )
+      }
+      const wallMs = performance.now() - started
+      assert.equal(
+        (db.prepare('SELECT count(*) AS n FROM messages_fts').get() as { n: number }).n,
+        0
+      )
+      assert.equal(
+        (db.prepare('SELECT count(*) AS n FROM conversation_fts').get() as { n: number }).n,
+        0
+      )
+      const walBytes = (await stat(`${path}-wal`)).size
+      intervals.sort((a, b) => a - b)
+      console.log(
+        JSON.stringify({
+          mode,
+          platform: process.platform,
+          node: process.version,
+          rows: 60000,
+          wallMs,
+          steps: intervals.length,
+          maxStepMs: intervals.at(-1),
+          p95StepMs: intervals[Math.floor(intervals.length * 0.95)],
+          walBytes
+        })
+      )
+    } finally {
+      reader?.close()
+      store.close()
+    }
+  }
+} finally {
+  await rm(root, { recursive: true, force: true })
+}
diff --git a/src/main/ai-vault-search/session-search-index-writer.ts b/src/main/ai-vault-search/session-search-index-writer.ts
index 1cd28600d16..b49e212560a 100644
--- a/src/main/ai-vault-search/session-search-index-writer.ts
+++ b/src/main/ai-vault-search/session-search-index-writer.ts
@@ -125,15 +125,6 @@ export class SessionSearchIndexWriter {
       )
   }
 
-  /** Paths of indexed files last modified before the cutoff, oldest first. */
-  filesOlderThan(cutoffMs: number): string[] {
-    return (
-      this.db
-        .prepare('SELECT path FROM files WHERE mtime_ms < ? ORDER BY mtime_ms')
-        .all(cutoffMs) as { path: string }[]
-    ).map((row) => row.path)
-  }
-
   removeFile(path: string): void {
     const existing = this.db
       .prepare('SELECT session_row_id FROM files WHERE path = ?')
diff --git a/src/main/ai-vault-search/session-search-refresh-lane.test.ts b/src/main/ai-vault-search/session-search-refresh-lane.test.ts
new file mode 100644
index 00000000000..59fa2b0b025
--- /dev/null
+++ b/src/main/ai-vault-search/session-search-refresh-lane.test.ts
@@ -0,0 +1,72 @@
+import { expect, it, vi } from 'vitest'
+import { SessionSearchRefreshLane } from './session-search-refresh-lane'
+import { waitForPromiseWithSignal } from '../../shared/abort-signal-reason'
+
+function barrier() {
+  let resolve!: () => void
+  return {
+    promise: new Promise<void>((r) => {
+      resolve = r
+    }),
+    release: () => resolve()
+  }
+}
+
+it('shares concurrent tiers, preserves a remaining reader, and reads fresh after completion', async () => {
+  const lane = new SessionSearchRefreshLane()
+  const gate = barrier()
+  const signals: AbortSignal[] = []
+  const refresh = vi.fn((signal: AbortSignal) => {
+    signals.push(signal)
+    return gate.promise
+  })
+  const first = new AbortController()
+  const a = lane.run({ claudeProjectsDir: '/isolated/a' }, refresh, first.signal)
+  const b = lane.run({ claudeProjectsDir: '/isolated/a' }, refresh)
+  first.abort()
+  await expect(a).rejects.toMatchObject({ name: 'AbortError' })
+  expect(refresh).toHaveBeenCalledTimes(1)
+  expect(signals[0].aborted).toBe(false)
+  gate.release()
+  await b
+  await lane.run({ claudeProjectsDir: '/isolated/a' }, refresh)
+  expect(refresh).toHaveBeenCalledTimes(2)
+})
+
+it('isolates roots and cancels abandoned work without poisoning a retry', async () => {
+  const lane = new SessionSearchRefreshLane()
+  const started = barrier()
+  const signals: AbortSignal[] = []
+  const refresh = vi.fn((signal: AbortSignal) => {
+    signals.push(signal)
+    if (signals.length === 2) {
+      started.release()
+    }
+    return waitForPromiseWithSignal(new Promise<void>(() => {}), signal)
+  })
+  const controller = new AbortController()
+  const a = lane.run({ codexSessionsDir: '/a' }, refresh, controller.signal).catch((e) => e)
+  const b = lane.run({ codexSessionsDir: '/b' }, refresh).catch((e) => e)
+  await started.promise
+  controller.abort()
+  expect(await a).toMatchObject({ name: 'AbortError' })
+  expect(signals[0].aborted).toBe(true)
+  expect(signals[1].aborted).toBe(false)
+  lane.cancel()
+  expect(await b).toMatchObject({ name: 'AbortError' })
+  await lane.run({ codexSessionsDir: '/a' }, async () => {})
+})
+
+it('does not start already-cancelled work and retries failures', async () => {
+  const lane = new SessionSearchRefreshLane()
+  const refresh = vi.fn(async () => {
+    throw new Error('scan failure')
+  })
+  await expect(lane.run({}, refresh, AbortSignal.abort())).rejects.toMatchObject({
+    name: 'AbortError'
+  })
+  expect(refresh).not.toHaveBeenCalled()
+  await expect(lane.run({}, refresh)).rejects.toThrow('scan failure')
+  await expect(lane.run({}, refresh)).rejects.toThrow('scan failure')
+  expect(refresh).toHaveBeenCalledTimes(2)
+})
diff --git a/src/main/ai-vault-search/session-search-refresh-lane.ts b/src/main/ai-vault-search/session-search-refresh-lane.ts
new file mode 100644
index 00000000000..a728dced190
--- /dev/null
+++ b/src/main/ai-vault-search/session-search-refresh-lane.ts
@@ -0,0 +1,54 @@
+import { waitForPromiseWithSignal, throwIfSignalAborted } from '../../shared/abort-signal-reason'
+import type { SessionSearchScanRoots } from './session-search-service'
+
+type Refresh = { controller: AbortController; promise: Promise<void>; users: number }
+
+/** Share concurrent query refreshes, never completed filesystem snapshots. */
+export class SessionSearchRefreshLane {
+  private readonly runs = new Map<string, Refresh>()
+
+  async run(
+    roots: SessionSearchScanRoots,
+    refresh: (signal: AbortSignal) => Promise<void>,
+    signal?: AbortSignal
+  ): Promise<void> {
+    throwIfSignalAborted(signal)
+    const key = JSON.stringify(Object.entries(roots).sort(([a], [b]) => a.localeCompare(b)))
+    let run = this.runs.get(key)
+    if (!run) {
+      const controller = new AbortController()
+      run = { controller, users: 0, promise: Promise.resolve() }
+      const current = run
+      run.promise = Promise.resolve()
+        .then(() => {
+          throwIfSignalAborted(controller.signal)
+          return refresh(controller.signal)
+        })
+        .finally(() => {
+          if (this.runs.get(key) === current) {
+            this.runs.delete(key)
+          }
+        })
+      this.runs.set(key, run)
+    }
+    run.users++
+    try {
+      await waitForPromiseWithSignal(run.promise, signal)
+    } finally {
+      run.users--
+      if (run.users === 0) {
+        run.controller.abort()
+        if (this.runs.get(key) === run) {
+          this.runs.delete(key)
+        }
+      }
+    }
+  }
+
+  cancel(): void {
+    for (const run of this.runs.values()) {
+      run.controller.abort()
+    }
+    this.runs.clear()
+  }
+}
diff --git a/src/main/ai-vault-search/session-search-retention-delete.test.ts b/src/main/ai-vault-search/session-search-retention-delete.test.ts
new file mode 100644
index 00000000000..28dd8d525fd
--- /dev/null
+++ b/src/main/ai-vault-search/session-search-retention-delete.test.ts
@@ -0,0 +1,152 @@
+import { mkdtemp, rm } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { expect, it } from 'vitest'
+import { SessionSearchStore } from './session-search-store'
+import {
+  deleteExpiredSearchFiles,
+  RETENTION_DELETE_ROWS_PER_STEP
+} from './session-search-retention-delete'
+
+function seed(store: SessionSearchStore, id: number, rows: number, mtime: number) {
+  const db = store.db
+  db.prepare(`INSERT INTO sessions(id,agent,session_id,file_path,title,cwd,cwd_key,resume_command)
+    VALUES (?, 'claude', ?, ?, 'synthetic retention', '/fixture', '/fixture', '')`).run(
+    id,
+    String(id),
+    String(id)
+  )
+  db.prepare('INSERT INTO files(path,byte_offset,mtime_ms,session_row_id) VALUES (?,1,?,?)').run(
+    String(id),
+    mtime,
+    id
+  )
+  db.exec('BEGIN')
+  for (let i = 0; i < rows; i++) {
+    const row = db
+      .prepare("INSERT INTO messages(session_row_id,role) VALUES (?,'user')")
+      .run(id).lastInsertRowid
+    db.prepare('INSERT INTO messages_fts(rowid,user_text) VALUES (?,?)').run(row, 'retentionneedle')
+    db.prepare('INSERT INTO conversation_fts(rowid,user_text) VALUES (?,?)').run(
+      row,
+      'retentionneedle'
+    )
+  }
+  db.exec('COMMIT')
+}
+
+it('yields within a large file while hiding partial rows and preserving unrelated sessions', async () => {
+  const store = new SessionSearchStore(':memory:')
+  seed(store, 1, 1025, 1)
+  seed(store, 2, 1, 200)
+  let previous = 1025
+  let steps = 0
+  try {
+    await deleteExpiredSearchFiles(
+      store.db,
+      100,
+      () => false,
+      () => {},
+      async () => {
+        const left = Number(
+          (
+            store.db.prepare('SELECT count(*) AS n FROM messages WHERE session_row_id=1').get() as {
+              n: number
+            }
+          ).n
+        )
+        expect(previous - left).toBeLessThanOrEqual(RETENTION_DELETE_ROWS_PER_STEP)
+        expect(previous - left).toBeGreaterThan(0)
+        previous = left
+        steps++
+        expect(store.search({ query: 'retentionneedle' }).hits.map((h) => h.sessionId)).toEqual([
+          '2'
+        ])
+      }
+    )
+    expect(steps).toBe(5)
+    expect(store.db.prepare('SELECT count(*) AS n FROM messages_fts').get()).toEqual({ n: 1 })
+    expect(store.db.prepare('SELECT count(*) AS n FROM conversation_fts').get()).toEqual({ n: 1 })
+    expect(store.db.prepare('SELECT count(*) AS n FROM search_pending_deletes').get()).toEqual({
+      n: 0
+    })
+  } finally {
+    store.close()
+  }
+})
+
+it('finishes an interrupted deletion after reopening even when history becomes unlimited', async () => {
+  const root = await mkdtemp(join(tmpdir(), 'ss-retention-resume-'))
+  const path = join(root, 'index.sqlite')
+  let store = new SessionSearchStore(path)
+  let closed = false
+  try {
+    seed(store, 1, 513, 1)
+    await deleteExpiredSearchFiles(
+      store.db,
+      100,
+      () => closed,
+      () => {},
+      async () => {
+        store.close()
+        closed = true
+      }
+    )
+    store = new SessionSearchStore(path)
+    closed = false
+    expect(store.search({ query: 'retentionneedle' }).hits).toEqual([])
+    expect(store.coverage().sessionsIndexed).toBe(0)
+    await store.purgeOlderThan(null)
+    expect(store.db.prepare('SELECT count(*) AS n FROM messages_fts').get()).toEqual({ n: 0 })
+    expect(store.db.prepare('SELECT count(*) AS n FROM sessions').get()).toEqual({ n: 0 })
+  } finally {
+    if (!closed) {
+      store.close()
+    }
+    await rm(root, { recursive: true, force: true })
+  }
+})
+
+it('does not orphan a replacement file when resuming an older deletion for the same path', async () => {
+  const store = new SessionSearchStore(':memory:')
+  try {
+    seed(store, 1, 2, 1)
+    store.db.exec(
+      "INSERT INTO search_pending_deletes VALUES ('1',1); DELETE FROM files WHERE path='1'"
+    )
+    seed(store, 2, 2, 1)
+    store.db.exec("UPDATE files SET path='1' WHERE path='2'")
+    await store.purgeOlderThan(100)
+    for (const table of [
+      'messages',
+      'messages_fts',
+      'conversation_fts',
+      'sessions',
+      'files',
+      'search_pending_deletes'
+    ]) {
+      expect(store.db.prepare(`SELECT count(*) AS n FROM ${table}`).get()).toEqual({ n: 0 })
+    }
+  } finally {
+    store.close()
+  }
+})
+
+it('cancels retention between batches and resumes without exposing a partial session', async () => {
+  const store = new SessionSearchStore(':memory:')
+  try {
+    seed(store, 1, 1025, 1)
+    const controller = new AbortController()
+    const purge = store.purgeOlderThan(100, controller.signal)
+    setImmediate(() => controller.abort())
+    await purge
+    const remaining = store.db.prepare('SELECT count(*) AS n FROM messages').get() as { n: number }
+    expect(remaining.n).toBeGreaterThan(0)
+    expect(remaining.n).toBeLessThan(1025)
+    expect(store.search({ query: 'retentionneedle' }).hits).toEqual([])
+    await store.purgeOlderThan(null)
+    expect(store.db.prepare('SELECT count(*) AS n FROM messages').get()).toEqual({ n: 0 })
+  } finally {
+    store.close()
+  }
+})
diff --git a/src/main/ai-vault-search/session-search-retention-delete.ts b/src/main/ai-vault-search/session-search-retention-delete.ts
new file mode 100644
index 00000000000..71c91da6ea5
--- /dev/null
+++ b/src/main/ai-vault-search/session-search-retention-delete.ts
@@ -0,0 +1,84 @@
+import { setImmediate as yieldToEventLoop } from 'node:timers/promises'
+import type SyncDatabase from '../sqlite/sync-database'
+import { inSessionParseFileLane } from '../ai-vault/session-parse-file-lane'
+
+export const RETENTION_DELETE_ROWS_PER_STEP = 256
+
+/** A durable tombstone hides partial deletes and lets a reopened store finish them. */
+export async function deleteExpiredSearchFiles(
+  db: SyncDatabase,
+  cutoffMs: number | null,
+  closed: () => boolean,
+  changed: () => void,
+  yieldStep: () => Promise<void> = yieldToEventLoop
+): Promise<void> {
+  const pending = db.prepare('SELECT path FROM search_pending_deletes').all() as { path: string }[]
+  const expired =
+    cutoffMs === null
+      ? []
+      : (db
+          .prepare('SELECT path FROM files WHERE mtime_ms < ? ORDER BY mtime_ms')
+          .all(cutoffMs) as { path: string }[])
+  for (const { path } of [...pending, ...expired]) {
+    if (closed()) {
+      return
+    }
+    await inSessionParseFileLane(path, async () => {
+      if (closed()) {
+        return
+      }
+      db.exec('BEGIN IMMEDIATE')
+      try {
+        const file = db
+          .prepare(`SELECT session_row_id FROM files WHERE path = ? AND mtime_ms < ?
+             AND path NOT IN (SELECT path FROM search_pending_deletes)`)
+          .get(path, cutoffMs ?? -Infinity) as { session_row_id: number | null } | undefined
+        if (file) {
+          if (file.session_row_id !== null) {
+            db.prepare(
+              'INSERT OR IGNORE INTO search_pending_deletes(path, session_row_id) VALUES (?, ?)'
+            ).run(path, file.session_row_id)
+          }
+          db.prepare('DELETE FROM files WHERE path = ?').run(path)
+        }
+        db.exec('COMMIT')
+        changed()
+      } catch (error) {
+        db.exec('ROLLBACK')
+        throw error
+      }
+      while (!closed()) {
+        const pending = db
+          .prepare('SELECT session_row_id FROM search_pending_deletes WHERE path = ?')
+          .get(path) as { session_row_id: number } | undefined
+        if (!pending) {
+          return
+        }
+        db.exec('BEGIN IMMEDIATE')
+        try {
+          const ids = db
+            .prepare('SELECT id FROM messages WHERE session_row_id = ? LIMIT ?')
+            .all(pending.session_row_id, RETENTION_DELETE_ROWS_PER_STEP) as { id: number }[]
+          const full = db.prepare('DELETE FROM messages_fts WHERE rowid = ?')
+          const conversation = db.prepare('DELETE FROM conversation_fts WHERE rowid = ?')
+          const message = db.prepare('DELETE FROM messages WHERE id = ?')
+          for (const { id } of ids) {
+            full.run(id)
+            conversation.run(id)
+            message.run(id)
+          }
+          if (ids.length < RETENTION_DELETE_ROWS_PER_STEP) {
+            db.prepare('DELETE FROM sessions WHERE id = ?').run(pending.session_row_id)
+            db.prepare('DELETE FROM search_pending_deletes WHERE path = ?').run(path)
+          }
+          db.exec('COMMIT')
+          changed()
+        } catch (error) {
+          db.exec('ROLLBACK')
+          throw error
+        }
+        await yieldStep()
+      }
+    })
+  }
+}
diff --git a/src/main/ai-vault-search/session-search-row-filter.ts b/src/main/ai-vault-search/session-search-row-filter.ts
index a2334bf575b..5a431d312ef 100644
--- a/src/main/ai-vault-search/session-search-row-filter.ts
+++ b/src/main/ai-vault-search/session-search-row-filter.ts
@@ -19,7 +19,10 @@ export function sessionRowFilter(
   args: AiVaultSearchArgs,
   split: AiVaultSearchQuerySplit
 ): SessionRowFilter {
-  const filter: SessionRowFilter = { conditions: [], values: [] }
+  const filter: SessionRowFilter = {
+    conditions: ['id NOT IN (SELECT session_row_id FROM search_pending_deletes)'],
+    values: []
+  }
   if (args.agents && args.agents.length > 0) {
     filter.conditions.push(`agent IN (${args.agents.map(() => '?').join(',')})`)
     filter.values.push(...args.agents)
diff --git a/src/main/ai-vault-search/session-search-schema.ts b/src/main/ai-vault-search/session-search-schema.ts
index be2cff5cb42..9701e9f4974 100644
--- a/src/main/ai-vault-search/session-search-schema.ts
+++ b/src/main/ai-vault-search/session-search-schema.ts
@@ -2,7 +2,7 @@ import { rmSync } from 'node:fs'
 import SyncDatabase from '../sqlite/sync-database'
 
 // Bump to drop and rebuild: the index is a cache over the transcripts, never a source.
-export const SESSION_SEARCH_SCHEMA_VERSION = 7
+export const SESSION_SEARCH_SCHEMA_VERSION = 8
 
 // unicode61 keeps `_ . - /` inside tokens so paths and identifiers match exactly;
 // the `identifiers` column carries the split form (see session-search-identifier-split).
@@ -43,6 +43,10 @@ CREATE TABLE IF NOT EXISTS files(
   size_bytes INTEGER,
   session_row_id INTEGER
 );
+CREATE TABLE IF NOT EXISTS search_pending_deletes(
+  path TEXT PRIMARY KEY,
+  session_row_id INTEGER NOT NULL UNIQUE
+);
 CREATE TABLE IF NOT EXISTS messages(
   id INTEGER PRIMARY KEY,
   session_row_id INTEGER NOT NULL,
diff --git a/src/main/ai-vault-search/session-search-service.ts b/src/main/ai-vault-search/session-search-service.ts
index 198f08f44f9..522e91da3e3 100644
--- a/src/main/ai-vault-search/session-search-service.ts
+++ b/src/main/ai-vault-search/session-search-service.ts
@@ -1,3 +1,4 @@
+import { SessionSearchRefreshLane } from './session-search-refresh-lane'
 import { recordSearchDiscovered } from './session-search-discovered-counts'
 import { withCursorChatMetaScan } from '../ai-vault/session-scanner-cursor-chat-meta'
 import { mkdirSync } from 'node:fs'
@@ -56,6 +57,7 @@ export class SessionSearchService {
   private policy: AiVaultSearchSettings
   private store: SessionSearchStore | null = null
   private backfillRun: Promise<void> | null = null
+  private readonly refreshLane = new SessionSearchRefreshLane()
   private searchesInFlight = 0
   private releaseBackfill: (() => void) | null = null
   private backfillController: AbortController | null = null
@@ -87,8 +89,14 @@ export class SessionSearchService {
     this.searchesInFlight += 1
     try {
       if (args.refresh !== false) {
-        await this.refreshRecent(roots, signal)
-        await this.reindexStale(signal)
+        await this.refreshLane.run(
+          roots,
+          async (sharedSignal) => {
+            await this.refreshRecent(roots, sharedSignal)
+            await this.reindexStale(sharedSignal)
+          },
+          signal
+        )
       }
       void backfill
       return store.search(args)
@@ -232,6 +240,7 @@ export class SessionSearchService {
   }
 
   private closeStore(): void {
+    this.refreshLane.cancel()
     const store = this.store
     this.store = null
     if (!store) {
@@ -287,9 +296,7 @@ export class SessionSearchService {
     store.setBackfillState('running')
     try {
       const cutoff = aiVaultSearchHistoryCutoffMs(this.policy.historyDays)
-      if (cutoff !== null) {
-        await store.purgeOlderThan(cutoff)
-      }
+      await store.purgeOlderThan(cutoff, signal)
       await ensureSessionParseCacheLoaded()
       const issues: AiVaultScanIssue[] = []
       const options: AiVaultScanOptions = { ...roots, signal }
diff --git a/src/main/ai-vault-search/session-search-store.ts b/src/main/ai-vault-search/session-search-store.ts
index 59f6c9b7157..bbf4dc0fcdb 100644
--- a/src/main/ai-vault-search/session-search-store.ts
+++ b/src/main/ai-vault-search/session-search-store.ts
@@ -1,3 +1,4 @@
+import { deleteExpiredSearchFiles } from './session-search-retention-delete'
 import type { AiVaultSession } from '../../shared/ai-vault-types'
 import { aiVaultSearchHistoryCutoffMs } from '../../shared/ai-vault-search-settings'
 import { setImmediate as yieldToEventLoop } from 'node:timers/promises'
@@ -140,33 +141,31 @@ export class SessionSearchStore implements SessionSearchIndexSink {
     }
   }
 
-  /**
-   * Drops every file last modified before the cutoff, one transaction per file
-   * so searches interleave, then hands the freed pages back so the index file
-   * shrinks (a full VACUUM on a multi-GB index takes half a minute).
-   */
-  async purgeOlderThan(cutoffMs: number): Promise<void> {
-    let paths: string[]
+  /** Hides expired sessions immediately, then removes their rows in resumable batches. */
+  async purgeOlderThan(cutoffMs: number | null, signal?: AbortSignal): Promise<void> {
     try {
-      paths = this.writer.filesOlderThan(cutoffMs)
+      await deleteExpiredSearchFiles(
+        this.db,
+        cutoffMs,
+        () => this.closed || signal?.aborted === true,
+        () => {
+          this.providerCounts = null
+        }
+      )
+      if (!this.closed && !signal?.aborted) {
+        await this.compact(signal)
+      }
     } catch (error) {
-      this.onError(error)
-      return
-    }
-    for (const path of paths) {
-      if (this.closed) {
-        return
+      if (!this.closed) {
+        this.onError(error)
       }
-      this.removeFile(path)
-      await yieldToEventLoop()
     }
-    await this.compact()
   }
 
-  private async compact(): Promise<void> {
+  private async compact(signal?: AbortSignal): Promise<void> {
     try {
       let freed = Number(this.db.pragma('freelist_count', { simple: true }))
-      while (!this.closed && freed > 0) {
+      while (!this.closed && !signal?.aborted && freed > 0) {
         this.db.pragma(`incremental_vacuum(${COMPACT_PAGES_PER_STEP})`)
         const remaining = Number(this.db.pragma('freelist_count', { simple: true }))
         // Why: without auto_vacuum the step is a no-op; never spin on it.
@@ -242,6 +241,7 @@ export class SessionSearchStore implements SessionSearchIndexSink {
       .prepare(
         `SELECT s.agent AS agent, COUNT(DISTINCT s.id) AS sessions, COUNT(m.id) AS messages
          FROM sessions s LEFT JOIN messages m ON m.session_row_id = s.id
+         WHERE s.id NOT IN (SELECT session_row_id FROM search_pending_deletes)
          GROUP BY s.agent ORDER BY s.agent`
       )
       .all() as { agent: AiVaultAgent; sessions: number; messages: number }[])
diff --git a/src/main/ai-vault/session-newest-files.test.ts b/src/main/ai-vault/session-newest-files.test.ts
new file mode 100644
index 00000000000..092def09a16
--- /dev/null
+++ b/src/main/ai-vault/session-newest-files.test.ts
@@ -0,0 +1,31 @@
+import { expect, it } from 'vitest'
+import { SessionNewestFiles } from './session-newest-files'
+import type { FileWithMtime } from './session-scanner-types'
+
+function file(i: number): FileWithMtime {
+  const mtimeMs = (i * 7919) % 997
+  return { path: String(i), mtimeMs, modifiedAt: new Date(mtimeMs).toISOString() }
+}
+
+it('retains at most 12 of 100,000 candidates with stable newest-first ties', () => {
+  const all = Array.from({ length: 100_000 }, (_, i) => file(i))
+  const retained = new SessionNewestFiles(12)
+  let peak = 0
+  for (const candidate of all) {
+    retained.add(candidate)
+    peak = Math.max(peak, retained.size)
+  }
+  expect(peak).toBe(12)
+  expect(retained.newest()).toEqual(all.sort((a, b) => b.mtimeMs - a.mtimeMs).slice(0, 12))
+})
+
+it('supports full backfill and empty requests', () => {
+  const all = new SessionNewestFiles(Infinity)
+  const none = new SessionNewestFiles(0)
+  for (let i = 0; i < 100; i++) {
+    all.add(file(i))
+    none.add(file(i))
+  }
+  expect(all.newest()).toHaveLength(100)
+  expect(none.newest()).toEqual([])
+})
diff --git a/src/main/ai-vault/session-newest-files.ts b/src/main/ai-vault/session-newest-files.ts
new file mode 100644
index 00000000000..cb20a62b34f
--- /dev/null
+++ b/src/main/ai-vault/session-newest-files.ts
@@ -0,0 +1,48 @@
+import type { FileWithMtime } from './session-scanner-types'
+
+/** Retain only the requested newest files, preserving traversal order on ties. */
+export class SessionNewestFiles {
+  private readonly files: FileWithMtime[] = []
+
+  private readonly limit: number
+
+  constructor(limit: number) {
+    this.limit = limit === Infinity ? limit : Math.max(0, Math.trunc(limit) || 0)
+  }
+
+  add(file: FileWithMtime): void {
+    if (!Number.isFinite(this.limit)) {
+      this.files.push(file)
+      return
+    }
+    if (this.limit <= 0) {
+      return
+    }
+    const last = this.files.at(-1)
+    if (this.files.length >= this.limit && last && file.mtimeMs <= last.mtimeMs) {
+      return
+    }
+    let low = 0
+    let high = this.files.length
+    while (low < high) {
+      const middle = (low + high) >>> 1
+      if (this.files[middle].mtimeMs >= file.mtimeMs) {
+        low = middle + 1
+      } else {
+        high = middle
+      }
+    }
+    this.files.splice(low, 0, file)
+    if (this.files.length > this.limit) {
+      this.files.pop()
+    }
+  }
+
+  get size(): number {
+    return this.files.length
+  }
+
+  newest(): FileWithMtime[] {
+    return this.files.sort((a, b) => b.mtimeMs - a.mtimeMs)
+  }
+}
diff --git a/src/main/ai-vault/session-scanner-directory-reader.test.ts b/src/main/ai-vault/session-scanner-directory-reader.test.ts
index e56acbfb758..1a578f661c7 100644
--- a/src/main/ai-vault/session-scanner-directory-reader.test.ts
+++ b/src/main/ai-vault/session-scanner-directory-reader.test.ts
@@ -61,3 +61,28 @@ describe('walkSessionFiles directory reader', () => {
     ).rejects.toBe(cancelled)
   })
 })
+
+it('visits file contents before descending further without retaining paths', async () => {
+  tempRoot = await mkdtemp(join(tmpdir(), 'orca-session-stream-'))
+  await writeFile(join(tempRoot, 'first.jsonl'), '{}\n')
+  await mkdir(join(tempRoot, 'nested'))
+  await writeFile(join(tempRoot, 'nested', 'second.jsonl'), '{}\n')
+  const visited: string[] = []
+  const readDirectory = vi.fn(async (path: string) => {
+    if (path.endsWith('nested')) {
+      expect(visited).toEqual([join(tempRoot!, 'first.jsonl')])
+    }
+    return (await readdir(path, { withFileTypes: true })).sort((a, b) =>
+      a.name.localeCompare(b.name)
+    )
+  })
+  const retained = await walkSessionFiles(tempRoot, 'claude', [], {
+    extensions: new Set(['.jsonl']),
+    readDirectory,
+    onFile: async (path) => {
+      visited.push(path)
+    }
+  })
+  expect(retained).toEqual([])
+  expect(visited).toHaveLength(2)
+})
diff --git a/src/main/ai-vault/session-scanner-discovery.ts b/src/main/ai-vault/session-scanner-discovery.ts
index 4a5ea303fd4..e152bc501ef 100644
--- a/src/main/ai-vault/session-scanner-discovery.ts
+++ b/src/main/ai-vault/session-scanner-discovery.ts
@@ -1,10 +1,11 @@
 import type { Dirent } from 'node:fs'
+import { SessionNewestFiles } from './session-newest-files'
 import { extname, join } from 'node:path'
 import type { AiVaultAgent, AiVaultScanIssue } from '../../shared/ai-vault-types'
 import { wslGatedReaddir, wslGatedStat } from '../native-chat/wsl-transcript-fs-access'
 import { WslTranscriptFsError } from '../native-chat/wsl-transcript-fs-gate'
 import { recordSessionScanIssue } from './session-scan-issues'
-import type { FileWithMtime, SessionFileDiscovery } from './session-scanner-types'
+import type { SessionFileDiscovery } from './session-scanner-types'
 import { errorMessage } from './session-scanner-values'
 
 export async function discoverFiles(args: {
@@ -18,18 +19,42 @@ export async function discoverFiles(args: {
   contentDependencyPath?: (path: string) => string | undefined | Promise<string | undefined>
   directoryPredicate?: (name: string, depth: number) => boolean
 }): Promise<SessionFileDiscovery> {
-  let paths: string[]
+  const files = new SessionNewestFiles(args.limit)
   try {
-    paths = await walkSessionFiles(args.rootDir, args.agent, args.issues, {
+    await walkSessionFiles(args.rootDir, args.agent, args.issues, {
       extensions: new Set(args.extensions),
       signal: args.signal,
       filePredicate: args.filePredicate,
-      directoryPredicate: args.directoryPredicate
+      directoryPredicate: args.directoryPredicate,
+      onFile: async (path) => {
+        args.signal?.throwIfAborted()
+        try {
+          const fileStat = await wslGatedStat(path, 'scan')
+          const dependencyStat = await optionalContentDependencyStat(
+            await args.contentDependencyPath?.(path)
+          )
+          args.signal?.throwIfAborted()
+          const mtimeMs = Math.max(fileStat.mtimeMs, dependencyStat?.mtimeMs ?? 0)
+          files.add({
+            path,
+            mtimeMs,
+            modifiedAt: new Date(mtimeMs).toISOString(),
+            sizeBytes: fileStat.size + (dependencyStat?.size ?? 0),
+            dev: fileStat.dev,
+            ino: fileStat.ino,
+            nlink: fileStat.nlink
+          })
+        } catch (err) {
+          args.signal?.throwIfAborted()
+          recordSessionScanIssue(args.issues, {
+            agent: args.agent,
+            path,
+            message: errorMessage(err)
+          })
+        }
+      }
     })
   } catch (err) {
-    // Why: discoverAiVaultSessionSources fans out with Promise.all, so one
-    // stalled distro would otherwise reject the whole vault scan — including
-    // every healthy local agent. Contain it to this root.
     if (!(err instanceof WslTranscriptFsError)) {
       throw err
     }
@@ -40,39 +65,7 @@ export async function discoverFiles(args: {
     })
     return { agent: args.agent, rootDir: args.rootDir, files: [] }
   }
-  const files: FileWithMtime[] = []
-  for (const path of paths) {
-    args.signal?.throwIfAborted()
-    try {
-      const fileStat = await wslGatedStat(path, 'scan')
-      const dependencyStat = await optionalContentDependencyStat(
-        await args.contentDependencyPath?.(path)
-      )
-      args.signal?.throwIfAborted()
-      const mtimeMs = Math.max(fileStat.mtimeMs, dependencyStat?.mtimeMs ?? 0)
-      files.push({
-        path,
-        mtimeMs,
-        modifiedAt: new Date(mtimeMs).toISOString(),
-        sizeBytes: fileStat.size + (dependencyStat?.size ?? 0),
-        dev: fileStat.dev,
-        ino: fileStat.ino,
-        nlink: fileStat.nlink
-      })
-    } catch (err) {
-      args.signal?.throwIfAborted()
-      recordSessionScanIssue(args.issues, {
-        agent: args.agent,
-        path,
-        message: errorMessage(err)
-      })
-    }
-  }
-  return {
-    agent: args.agent,
-    rootDir: args.rootDir,
-    files: files.sort((left, right) => right.mtimeMs - left.mtimeMs).slice(0, args.limit)
-  }
+  return { agent: args.agent, rootDir: args.rootDir, files: files.newest() }
 }
 
 async function optionalContentDependencyStat(
@@ -104,6 +97,7 @@ export async function walkSessionFiles(
     directoryPredicate?: (name: string, depth: number) => boolean
     readDirectory?: (dirPath: string) => Promise<Dirent[]>
     signal?: AbortSignal
+    onFile?: (path: string) => Promise<void>
   },
   depth = 0
 ): Promise<string[]> {
@@ -140,7 +134,11 @@ export async function walkSessionFiles(
       options.extensions.has(extname(entry.name).toLowerCase()) &&
       (options.filePredicate?.(fullPath) ?? true)
     ) {
-      files.push(fullPath)
+      if (options.onFile) {
+        await options.onFile(fullPath)
+      } else {
+        files.push(fullPath)
+      }
     }
   }
   return files
diff --git a/src/renderer/src/components/right-sidebar/ai-vault-search-coverage-poll.test.ts b/src/renderer/src/components/right-sidebar/ai-vault-search-coverage-poll.test.ts
index bba4291f1c4..13b6063f3a9 100644
--- a/src/renderer/src/components/right-sidebar/ai-vault-search-coverage-poll.test.ts
+++ b/src/renderer/src/components/right-sidebar/ai-vault-search-coverage-poll.test.ts
@@ -104,3 +104,25 @@ describe('useAiVaultSearchCoveragePoll', () => {
     expect(result.current).toBeNull()
   })
 })
+
+it('drops coverage from the previous runtime immediately and polls the new owner', async () => {
+  const { result, rerender } = renderHook(
+    ({ host }) => useAiVaultSearchCoveragePoll(true, null, host),
+    { initialProps: { host: 'runtime:a' }, wrapper }
+  )
+  await act(async () => {})
+  expect(result.current?.sessionsIndexed).toBe(5)
+  let release!: (value: AiVaultSearchCoverage) => void
+  searchCoverage.mockImplementation(
+    () =>
+      new Promise((resolve) => {
+        release = resolve
+      })
+  )
+  rerender({ host: 'runtime:b' })
+  expect(result.current).toBeNull()
+  await act(async () => {
+    release({ ...coverage('complete'), sessionsIndexed: 9 })
+  })
+  expect(result.current?.sessionsIndexed).toBe(9)
+})
diff --git a/src/renderer/src/components/right-sidebar/ai-vault-search-coverage-poll.ts b/src/renderer/src/components/right-sidebar/ai-vault-search-coverage-poll.ts
index 07161c2e399..bc53e43d40b 100644
--- a/src/renderer/src/components/right-sidebar/ai-vault-search-coverage-poll.ts
+++ b/src/renderer/src/components/right-sidebar/ai-vault-search-coverage-poll.ts
@@ -13,9 +13,11 @@ export const AI_VAULT_SEARCH_COVERAGE_POLL_MS = 4_000
  */
 export function useAiVaultSearchCoveragePoll(
   enabled: boolean,
-  latest: AiVaultSearchCoverage | null = null
+  latest: AiVaultSearchCoverage | null = null,
+  ownerKey = ''
 ): AiVaultSearchCoverage | null {
   const [snapshot, setSnapshot] = useState<{
+    ownerKey: string
     source: AiVaultSearchCoverage | null
     value: AiVaultSearchCoverage
   } | null>(null)
@@ -41,7 +43,7 @@ export function useAiVaultSearchCoveragePoll(
           if (stopped || issued !== generation) {
             return
           }
-          setSnapshot({ source: latest, value: next })
+          setSnapshot({ ownerKey, source: latest, value: next })
         })
         .catch(() => undefined)
     }
@@ -50,7 +52,11 @@ export function useAiVaultSearchCoveragePoll(
       stopped = true
       clearInterval(interval)
     }
-  }, [enabled, latest])
+  }, [enabled, latest, ownerKey])
 
-  return enabled ? (snapshot?.source === latest ? snapshot.value : latest) : null
+  return enabled
+    ? snapshot?.ownerKey === ownerKey && snapshot.source === latest
+      ? snapshot.value
+      : latest
+    : null
 }
diff --git a/src/renderer/src/components/right-sidebar/ai-vault-session-search-request.test.ts b/src/renderer/src/components/right-sidebar/ai-vault-session-search-request.test.ts
index a3aedc76fc1..6797f7c37a1 100644
--- a/src/renderer/src/components/right-sidebar/ai-vault-session-search-request.test.ts
+++ b/src/renderer/src/components/right-sidebar/ai-vault-session-search-request.test.ts
@@ -214,3 +214,38 @@ describe('useAiVaultSessionSearchRequest', () => {
     expect(searchSessions.mock.calls[0]?.[0]).toMatchObject({ query: 'alpha', tier: 'full' })
   })
 })
+
+it('retires retained and in-flight results when the execution host changes with the same query', async () => {
+  const resolvers: ((result: AiVaultSearchResult) => void)[] = []
+  searchSessions.mockImplementation(
+    () => new Promise<AiVaultSearchResult>((resolve) => resolvers.push(resolve))
+  )
+  const { rerender, result } = renderHook(
+    ({ host }: { host: string }) => useAiVaultSessionSearchRequest(argsFor('alpha'), 0, host),
+    { initialProps: { host: 'runtime:a' }, wrapper }
+  )
+  act(() => {
+    vi.advanceTimersByTime(AI_VAULT_SEARCH_TYPING_DELAY_MS)
+  })
+  await act(async () => {
+    resolvers[0](searchResult('host-a'))
+  })
+  expect(result.current.result?.repairedTerms).toEqual(['host-a'])
+  act(() => {
+    vi.advanceTimersByTime(AI_VAULT_SEARCH_SETTLED_DELAY_MS)
+  })
+  rerender({ host: 'runtime:b' })
+  expect(result.current.result).toBeNull()
+  await act(async () => {
+    resolvers[1](searchResult('late-host-a'))
+  })
+  expect(result.current.result).toBeNull()
+  act(() => {
+    vi.advanceTimersByTime(AI_VAULT_SEARCH_SETTLED_DELAY_MS)
+  })
+  await act(async () => {
+    resolvers.at(-1)!(searchResult('host-b'))
+  })
+  expect(result.current.result?.repairedTerms).toEqual(['host-b'])
+  expect(searchSessions).toHaveBeenCalledTimes(4)
+})
diff --git a/src/renderer/src/components/right-sidebar/ai-vault-session-search-request.ts b/src/renderer/src/components/right-sidebar/ai-vault-session-search-request.ts
index 638bd8375da..5247f95497e 100644
--- a/src/renderer/src/components/right-sidebar/ai-vault-session-search-request.ts
+++ b/src/renderer/src/components/right-sidebar/ai-vault-session-search-request.ts
@@ -19,6 +19,7 @@ export type AiVaultSearchRequestState = {
 }
 
 type SettledSearch = {
+  ownerKey: string
   full: boolean
   key: string
   result: AiVaultSearchResult | null
@@ -40,7 +41,8 @@ type SettledSearch = {
 export function useAiVaultSessionSearchRequest(
   args: AiVaultSearchArgs | null,
   /** Bumped on Enter: runs the full tier now instead of waiting out the debounce. */
-  flushSignal = 0
+  flushSignal = 0,
+  ownerKey = ''
 ): AiVaultSearchRequestState {
   const [settled, setSettled] = useState<SettledSearch | null>(null)
   const sequenceRef = useRef(0)
@@ -48,31 +50,35 @@ export function useAiVaultSessionSearchRequest(
   // restart the debounce on every parent render.
   const argsKey = args ? JSON.stringify(args) : ''
 
-  const issue = useCallback((key: string, overrides: Partial<AiVaultSearchArgs>): void => {
-    if (!key) {
-      return
-    }
-    const requestArgs = JSON.parse(key) as AiVaultSearchArgs
-    sequenceRef.current += 1
-    const sequence = sequenceRef.current
-    void window.api.aiVault
-      .searchSessions({ ...requestArgs, ...overrides })
-      .then((result) => {
-        if (sequenceRef.current === sequence) {
-          setSettled({ key, result, error: null, full: overrides.tier === 'full' })
-        }
-      })
-      .catch((error: unknown) => {
-        if (sequenceRef.current === sequence) {
-          setSettled({
-            key,
-            full: true,
-            result: null,
-            error: error instanceof Error ? error.message : String(error)
-          })
-        }
-      })
-  }, [])
+  const issue = useCallback(
+    (key: string, overrides: Partial<AiVaultSearchArgs>): void => {
+      if (!key) {
+        return
+      }
+      const requestArgs = JSON.parse(key) as AiVaultSearchArgs
+      sequenceRef.current += 1
+      const sequence = sequenceRef.current
+      void window.api.aiVault
+        .searchSessions({ ...requestArgs, ...overrides })
+        .then((result) => {
+          if (sequenceRef.current === sequence) {
+            setSettled({ ownerKey, key, result, error: null, full: overrides.tier === 'full' })
+          }
+        })
+        .catch((error: unknown) => {
+          if (sequenceRef.current === sequence) {
+            setSettled({
+              ownerKey,
+              key,
+              full: true,
+              result: null,
+              error: error instanceof Error ? error.message : String(error)
+            })
+          }
+        })
+    },
+    [ownerKey]
+  )
 
   // Why: a flush has to cancel the debounce the args effect armed, and the two
   // effects cannot share locals, so the args effect publishes its cancel.
@@ -114,8 +120,9 @@ export function useAiVaultSessionSearchRequest(
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [flushSignal, issue])
 
-  const current = settled?.key === argsKey ? settled : null
-  const previous = current === null && argsKey !== '' ? (settled?.result ?? null) : null
+  const owned = settled?.ownerKey === ownerKey ? settled : null
+  const current = owned?.key === argsKey ? owned : null
+  const previous = current === null && argsKey !== '' ? (owned?.result ?? null) : null
   return {
     result: current?.result ?? previous,
     loading: argsKey !== '' && current === null && previous === null,
diff --git a/src/renderer/src/components/right-sidebar/ai-vault-session-search-results.ts b/src/renderer/src/components/right-sidebar/ai-vault-session-search-results.ts
index 1b4b41718b7..091bd95db92 100644
--- a/src/renderer/src/components/right-sidebar/ai-vault-session-search-results.ts
+++ b/src/renderer/src/components/right-sidebar/ai-vault-session-search-results.ts
@@ -79,12 +79,17 @@ export function useAiVaultSessionSearchResults(input: {
     }
   }, [agents, enabled, newestFirst, query, scopePaths, supportedHost])
 
-  const { error, loading, result, updating } = useAiVaultSessionSearchRequest(args, flushSignal)
+  const { error, loading, result, updating } = useAiVaultSessionSearchRequest(
+    args,
+    flushSignal,
+    executionHostScope
+  )
   // With an empty box no search runs, so the panel reads coverage directly to
   // report what is already searchable while the backfill is still going.
   const polledCoverage = useAiVaultSearchCoveragePoll(
     enabled && supportedHost,
-    result?.coverage ?? null
+    result?.coverage ?? null,
+    executionHostScope
   )
   // Desktop search always reads this machine's index; a paired web client's
   // reads its runtime host, which is the scope it is pinned to.
diff --git a/src/renderer/src/web/web-ai-vault-search-compatibility.test.ts b/src/renderer/src/web/web-ai-vault-search-compatibility.test.ts
new file mode 100644
index 00000000000..927e9c7927c
--- /dev/null
+++ b/src/renderer/src/web/web-ai-vault-search-compatibility.test.ts
@@ -0,0 +1,69 @@
+import { afterEach, beforeEach, expect, it, vi } from 'vitest'
+import {
+  installBrowserGlobals,
+  writeStoredRuntimeEnvironment
+} from './web-preload-api-test-harness'
+import type { RuntimeRpcResponse } from '../../../shared/runtime-rpc-envelope'
+
+beforeEach(() => vi.resetModules())
+afterEach(() => {
+  vi.unstubAllGlobals()
+  vi.doUnmock('./web-runtime-client')
+})
+
+it('preserves legacy search results and surfaces old-host or disconnected errors without local fallback', async () => {
+  const calls: { method: string; params: unknown }[] = []
+  let failure: string | null = null
+  const legacy = {
+    hits: [],
+    route: 'or',
+    durationMs: 1,
+    coverage: {
+      sessionsIndexed: 1,
+      messagesIndexed: 2,
+      providers: [],
+      backfill: 'complete',
+      filesPending: 0,
+      lastIndexedAt: null
+    }
+  }
+  vi.doMock('./web-runtime-client', () => ({
+    WebRuntimeClient: class {
+      call(method: string, params: unknown): Promise<RuntimeRpcResponse<unknown>> {
+        calls.push({ method, params })
+        return Promise.resolve(
+          failure
+            ? {
+                id: 'fixture',
+                _meta: { runtimeId: 'host-a' },
+                ok: false,
+                error: { code: failure, message: failure }
+              }
+            : { id: 'fixture', _meta: { runtimeId: 'host-a' }, ok: true, result: legacy }
+        )
+      }
+      close(): void {}
+    }
+  }))
+  const globals = installBrowserGlobals('Linux')
+  writeStoredRuntimeEnvironment(globals.storage, 'host-a')
+  const { installWebPreloadApi } = await import('./web-preload-api')
+  installWebPreloadApi()
+  await expect(globals.window.api.aiVault.searchSessions({ query: 'needle' })).resolves.toEqual(
+    legacy
+  )
+  expect(calls).toEqual([
+    {
+      method: 'aiVault.searchSessions',
+      params: { query: 'needle', executionHostId: 'runtime:host-a' }
+    }
+  ])
+  for (const error of ['method_not_found', 'connection_closed']) {
+    failure = error
+    await expect(
+      globals.window.api.aiVault.searchSessions({ query: 'needle' })
+    ).rejects.toMatchObject({ code: error })
+  }
+  expect(calls).toHaveLength(3)
+  expect(calls.every((call) => call.method === 'aiVault.searchSessions')).toBe(true)
+})