diff --git a/src/shared/ai-vault-session-depth.test.ts b/src/shared/ai-vault-session-depth.test.ts
index 86ceace2215..c262d521449 100644
--- a/src/shared/ai-vault-session-depth.test.ts
+++ b/src/shared/ai-vault-session-depth.test.ts
@@ -1,5 +1,6 @@
-import { describe, expect, it } from 'vitest'
+import { describe, expect, it, vi } from 'vitest'
 import type { AiVaultListResult, AiVaultSession } from './ai-vault-types'
+import { isPathInsideOrEqual } from './cross-platform-path'
 import {
   aiVaultScanLimit,
   aiVaultSessionDepthCovers,
@@ -83,3 +84,43 @@ describe('Agent Session History depth', () => {
     expect(truncateAiVaultListResult(loaded, 'unlimited')).toBe(loaded)
   })
 })
+
+describe('Agent Session History scope truncation', () => {
+  it('normalizes scope roots and candidate cwd once per truncation pass', () => {
+    const loaded = result(
+      Array.from({ length: 1000 }, (_, i) => session(`id-${i}`, `/other/${i}`, i))
+    )
+    const scopes = Array.from({ length: 100 }, (_, i) => `/repo/${i}`)
+    const normalize = vi.spyOn(String.prototype, 'normalize')
+    let selected: AiVaultListResult
+    try {
+      selected = truncateAiVaultListResult(loaded, 10, scopes)
+      expect(normalize.mock.calls.length).toBeLessThanOrEqual(1100)
+    } finally {
+      normalize.mockRestore()
+    }
+    expect(selected.sessions).toEqual(loaded.sessions.slice(0, 10))
+  })
+
+  it('selects scoped sessions identically to the pre-hoist path predicate', () => {
+    const cases = [
+      ['C:\\Users\\Ada\\repo', 'c:/users/ada/repo/app'],
+      ['C:/Users/Ada/repo/', 'C:\\Users\\Ada\\repo'],
+      ['C:\\Users\\Ada\\repo', 'C:\\Users\\Ada\\repo-other'],
+      ['//wsl.localhost/Ubuntu/home/Ada/Repo', '//wsl$/Ubuntu/home/Ada/Repo/App'],
+      ['//wsl.localhost/Ubuntu/home/ada/repo', '//wsl.localhost/Debian/home/ada/repo'],
+      ['/Users/ada/repo', '/Users/ada/repo//app/'],
+      ['/Users/ada/repo', '/Users/ada/repository'],
+      ['/', '/anywhere']
+    ]
+    for (const [scope, cwd] of cases) {
+      const loaded = result([session('scoped', cwd!, 0)])
+      const selected = truncateAiVaultListResult(loaded, 0, [scope!])
+      expect({ scope, cwd, kept: selected.sessions.length === 1 }).toEqual({
+        scope,
+        cwd,
+        kept: isPathInsideOrEqual(scope!, cwd!)
+      })
+    }
+  })
+})
diff --git a/src/shared/ai-vault-session-depth.ts b/src/shared/ai-vault-session-depth.ts
index 6e12574c545..8499d4c0dc6 100644
--- a/src/shared/ai-vault-session-depth.ts
+++ b/src/shared/ai-vault-session-depth.ts
@@ -1,4 +1,7 @@
-import { isPathInsideOrEqual } from './cross-platform-path'
+import {
+  createNormalizedPathInsideOrEqualMatcher,
+  normalizeRuntimePathForComparison
+} from './cross-platform-path'
 import type { AiVaultListArgs, AiVaultListResult } from './ai-vault-types'
 
 export const DEFAULT_AI_VAULT_SCAN_LIMIT = 1000
@@ -40,10 +43,12 @@ export function truncateAiVaultListResult(
   }
   const selectedIds = new Set(result.sessions.slice(0, depth).map((session) => session.id))
   if (scopePaths.length > 0) {
+    const scopeMatchers = scopePaths.map(createNormalizedPathInsideOrEqualMatcher)
     let scopedCount = 0
     for (const session of result.sessions) {
       const cwd = session.cwd
-      if (cwd && scopePaths.some((scopePath) => isPathInsideOrEqual(scopePath, cwd))) {
+      const normalizedCwd = cwd ? normalizeRuntimePathForComparison(cwd) : null
+      if (normalizedCwd !== null && scopeMatchers.some((matches) => matches(normalizedCwd))) {
         selectedIds.add(session.id)
         if (++scopedCount >= depth) {
           break
diff --git a/src/shared/ai-vault-session-filters.test.ts b/src/shared/ai-vault-session-filters.test.ts
index 746c18010ec..4efd5b86036 100644
--- a/src/shared/ai-vault-session-filters.test.ts
+++ b/src/shared/ai-vault-session-filters.test.ts
@@ -1,4 +1,4 @@
-import { describe, expect, it } from 'vitest'
+import { describe, expect, it, vi } from 'vitest'
 import type { AiVaultSession } from './ai-vault-types'
 import {
   agentLabel,
@@ -9,6 +9,8 @@ import {
   parseVaultQuery
 } from './ai-vault-session-filters'
 import { sessionPreviewSearchText } from './ai-vault-session-display'
+import { isPathInsideOrEqual } from './cross-platform-path'
+import { parseWslUncPath } from './wsl-paths'
 
 const baseSession: AiVaultSession = {
   id: 'claude:1',
@@ -198,3 +200,162 @@ describe('/shared ai-vault-session-filters (lifted core)', () => {
     expect(sessionPreviewSearchText(baseSession)).toContain('scope tabs')
   })
 })
+
+describe('/shared ai-vault-session-filters (hoisted matchers and sort keys)', () => {
+  it('prepares workspace path matching once for a large session filter pass', () => {
+    const sessions = Array.from({ length: 1000 }, (_, i) => ({
+      ...baseSession,
+      id: String(i),
+      cwd: `/other/${i}`
+    }))
+    const activeWorktreePaths = Array.from({ length: 100 }, (_, i) => `/repo/${i}`)
+    const normalize = vi.spyOn(String.prototype, 'normalize')
+    try {
+      expect(
+        filterAiVaultSessions(sessions, {
+          query: '',
+          agents: ['claude'],
+          scope: 'workspace',
+          sort: 'updated',
+          activeWorktreePaths,
+          hideEmptySessions: false
+        })
+      ).toEqual([])
+      expect(normalize.mock.calls.length).toBeLessThanOrEqual(1100)
+    } finally {
+      normalize.mockRestore()
+    }
+  })
+
+  it('does not read transcript previews for empty or field-only queries', () => {
+    let reads = 0
+    const sessions = Array.from({ length: 1000 }, (_, i) => ({
+      ...baseSession,
+      id: String(i),
+      get previewMessages() {
+        reads++
+        return baseSession.previewMessages
+      }
+    }))
+    for (const query of ['', 'repo:repo', 'path:app']) {
+      expect(
+        filterAiVaultSessions(sessions, {
+          query,
+          agents: ['claude'],
+          scope: 'all',
+          sort: 'updated',
+          activeWorktreePaths: [],
+          hideEmptySessions: false
+        })
+      ).toHaveLength(1000)
+    }
+    expect(reads).toBe(0)
+    expect(
+      filterAiVaultSessions(sessions, {
+        query: 'scope',
+        agents: ['claude'],
+        scope: 'all',
+        sort: 'updated',
+        activeWorktreePaths: [],
+        hideEmptySessions: false
+      })
+    ).toHaveLength(1000)
+    expect(reads).toBeGreaterThan(0)
+  })
+
+  it('parses each sort timestamp once with original ordering, including invalid dates', () => {
+    const sessions = Array.from({ length: 2000 }, (_, i) => ({
+      ...baseSession,
+      id: String(i),
+      updatedAt:
+        i % 131 === 0
+          ? 'invalid'
+          : new Date(1700000000000 + ((i * 173) % 1999) * 1000).toISOString()
+    }))
+    const parse = vi.spyOn(Date, 'parse')
+    let actual: AiVaultSession[]
+    let expected: AiVaultSession[]
+    try {
+      expected = [...sessions].sort(
+        (a, b) => Date.parse(b.updatedAt ?? b.modifiedAt) - Date.parse(a.updatedAt ?? a.modifiedAt)
+      )
+      expect(parse.mock.calls.length).toBeGreaterThan(10_000)
+      parse.mockClear()
+      actual = filterAiVaultSessions(sessions, {
+        query: '',
+        agents: ['claude'],
+        scope: 'all',
+        sort: 'updated',
+        activeWorktreePaths: [],
+        hideEmptySessions: false
+      })
+      expect(parse).toHaveBeenCalledTimes(2000)
+    } finally {
+      parse.mockRestore()
+    }
+    actual.forEach((session, i) => expect(session).toBe(expected[i]))
+  })
+
+  it('matches workspace scope identically to the pre-hoist path predicate', () => {
+    // The hoisted matcher must agree with isPathInsideOrEqual on every spelling the
+    // supported hosts produce: Windows case/separator folding, trailing separators,
+    // both WSL UNC aliases, /mnt drive mounts and near-miss sibling directories.
+    const cases: [workspace: string, cwd: string][] = [
+      ['C:\\Users\\Ada\\repo', 'c:/users/ada/repo/app'],
+      ['C:/Users/Ada/repo/', 'C:\\Users\\Ada\\repo'],
+      ['C:\\Users\\Ada\\repo', 'C:\\Users\\Ada\\repo-other'],
+      ['C:\\', 'C:\\anything'],
+      ['//wsl.localhost/Ubuntu/home/ada/repo', '//wsl$/Ubuntu/home/ada/repo/app'],
+      ['//wsl.localhost/Ubuntu/home/Ada/Repo', '//wsl$/Ubuntu/home/Ada/Repo/App'],
+      ['//wsl.localhost/Ubuntu/home/Ada/Repo', '//wsl$/Ubuntu/home/ada/repo/App'],
+      ['//wsl$/Ubuntu/home/ada/repo', '//WSL.LOCALHOST/ubuntu/home/ada/repo'],
+      ['//wsl.localhost/Ubuntu/home/ada/repo', '//wsl.localhost/Debian/home/ada/repo'],
+      ['//wsl.localhost/Ubuntu/mnt/c/work', '/mnt/c/work/app'],
+      ['/Users/ada/repo', '/Users/ada/repo//app/'],
+      ['/Users/ada/repo', '/Users/Ada/repo/app'],
+      ['/Users/ada/repo', '/Users/ada/repository'],
+      ['/', '/anywhere']
+    ]
+    for (const [workspace, cwd] of cases) {
+      const expected =
+        isPathInsideOrEqual(workspace, cwd) ||
+        (parseWslUncPath(workspace)
+          ? isPathInsideOrEqual(parseWslUncPath(workspace)!.linuxPath, cwd)
+          : false)
+      const actual = filterAiVaultSessions([{ ...baseSession, cwd }], {
+        query: '',
+        agents: ['claude'],
+        scope: 'workspace',
+        sort: 'updated',
+        activeWorktreePaths: [workspace],
+        hideEmptySessions: false
+      })
+      expect({ workspace, cwd, matched: actual.length === 1 }).toEqual({
+        workspace,
+        cwd,
+        matched: expected
+      })
+    }
+  })
+
+  it('orders by creation time identically to the per-comparison parse', () => {
+    const sessions = Array.from({ length: 500 }, (_, i) => ({
+      ...baseSession,
+      id: String(i),
+      createdAt:
+        i % 37 === 0 ? 'invalid' : new Date(1700000000000 + ((i * 91) % 499) * 1000).toISOString()
+    }))
+    const expected = [...sessions].sort(
+      (a, b) => Date.parse(b.createdAt ?? b.modifiedAt) - Date.parse(a.createdAt ?? a.modifiedAt)
+    )
+    const actual = filterAiVaultSessions(sessions, {
+      query: '',
+      agents: ['claude'],
+      scope: 'all',
+      sort: 'created',
+      activeWorktreePaths: [],
+      hideEmptySessions: false
+    })
+    actual.forEach((session, i) => expect(session).toBe(expected[i]))
+  })
+})
diff --git a/src/shared/ai-vault-session-filters.ts b/src/shared/ai-vault-session-filters.ts
index 46fafbc8efd..7a0708151ed 100644
--- a/src/shared/ai-vault-session-filters.ts
+++ b/src/shared/ai-vault-session-filters.ts
@@ -3,7 +3,7 @@
 // Metro only watches mobile/ + repo-root src/shared, never src/renderer.
 // INVARIANT: /shared is a leaf — this module must NOT import from src/renderer.
 import {
-  isPathInsideOrEqual,
+  createNormalizedPathInsideOrEqualMatcher,
   normalizeRuntimePathForComparison,
   normalizeRuntimePathSeparators
 } from './cross-platform-path'
@@ -79,45 +79,50 @@ export function filterAiVaultSessions(
 
   const agentSet = new Set(filters.agents)
   const parsedQuery = parseVaultQuery(filters.query)
+  const workspaceMatchers =
+    filters.scope === 'workspace'
+      ? filters.activeWorktreePaths.map(createAiVaultWorkspaceMatcher)
+      : []
 
-  return sessions
-    .filter((session) => {
-      if (!agentSet.has(session.agent)) {
+  const filtered = sessions.filter((session) => {
+    if (!agentSet.has(session.agent)) {
+      return false
+    }
+    // Hide plain empty sessions, but keep sessions with resumable content
+    // (some parsers only learn turns from previews, e.g. Grok) and zero-turn
+    // sessions that still carry recoverable content (queued prompts /
+    // subagent transcripts) so a lost conversation is surfaced distinctly.
+    if (
+      filters.hideEmptySessions &&
+      !isAiVaultSessionResumableContent(session) &&
+      !isAiVaultSessionRecoverableEmpty(session)
+    ) {
+      return false
+    }
+    if (filters.scope === 'workspace') {
+      const cwd = session.cwd
+      const normalizedCwd = cwd ? normalizeRuntimePathForComparison(cwd) : null
+      if (normalizedCwd === null || !workspaceMatchers.some((matches) => matches(normalizedCwd))) {
         return false
       }
-      // Hide plain empty sessions, but keep sessions with resumable content
-      // (some parsers only learn turns from previews, e.g. Grok) and zero-turn
-      // sessions that still carry recoverable content (queued prompts /
-      // subagent transcripts) so a lost conversation is surfaced distinctly.
-      if (
-        filters.hideEmptySessions &&
-        !isAiVaultSessionResumableContent(session) &&
-        !isAiVaultSessionRecoverableEmpty(session)
-      ) {
+    }
+    if (filters.scope === 'project') {
+      if (!filters.activeProjectKey) {
         return false
       }
-      if (filters.scope === 'workspace') {
-        const cwd = session.cwd
-        if (
-          !cwd ||
-          !filters.activeWorktreePaths.some((pathValue) =>
-            isAiVaultSessionInWorkspacePath(pathValue, cwd)
-          )
-        ) {
-          return false
-        }
+      if (filters.sessionProjectById?.get(session.id)?.key !== filters.activeProjectKey) {
+        return false
       }
-      if (filters.scope === 'project') {
-        if (!filters.activeProjectKey) {
-          return false
-        }
-        if (filters.sessionProjectById?.get(session.id)?.key !== filters.activeProjectKey) {
-          return false
-        }
-      }
-      return matchesQuery(session, parsedQuery, filters)
-    })
-    .sort((left, right) => compareSessions(left, right, filters.sort))
+    }
+    return matchesQuery(session, parsedQuery, filters)
+  })
+  if (filtered.length < 2) {
+    return filtered
+  }
+  return filtered
+    .map((session) => ({ session, time: sessionSortTime(session, filters.sort) }))
+    .sort((left, right) => right.time - left.time)
+    .map(({ session }) => session)
 }
 
 export function groupAiVaultSessions(
@@ -206,48 +211,48 @@ function matchesQuery(
   parsed: ParsedQuery,
   filters: Pick<AiVaultSessionFilterState, 'sessionProjectById' | 'projectLabelByKey'>
 ): boolean {
-  const searchable = [
-    session.title,
-    session.sessionId,
-    session.agent,
-    session.branch,
-    session.model,
-    session.cwd,
-    session.filePath,
-    sessionPreviewSearchText(session)
-  ]
-    .filter(Boolean)
-    .join(' ')
-    .toLowerCase()
-
-  if (parsed.terms.some((term) => !searchable.includes(term))) {
-    return false
+  if (parsed.terms.length > 0) {
+    const searchable = [
+      session.title,
+      session.sessionId,
+      session.agent,
+      session.branch,
+      session.model,
+      session.cwd,
+      session.filePath,
+      sessionPreviewSearchText(session)
+    ]
+      .filter(Boolean)
+      .join(' ')
+      .toLowerCase()
+    if (parsed.terms.some((term) => !searchable.includes(term))) {
+      return false
+    }
   }
-
-  const sessionProject = filters.sessionProjectById?.get(session.id)
-  const repoLabel = (
-    sessionProject?.kind === 'repo'
-      ? (filters.projectLabelByKey?.get(sessionProject.key) ?? sessionProject.label)
-      : folderLabel(session.cwd)
-  ).toLowerCase()
-  if (parsed.repoTerms.some((term) => !repoLabel.includes(term))) {
-    return false
+  if (parsed.repoTerms.length > 0) {
+    const sessionProject = filters.sessionProjectById?.get(session.id)
+    const repoLabel = (
+      sessionProject?.kind === 'repo'
+        ? (filters.projectLabelByKey?.get(sessionProject.key) ?? sessionProject.label)
+        : folderLabel(session.cwd)
+    ).toLowerCase()
+    if (parsed.repoTerms.some((term) => !repoLabel.includes(term))) {
+      return false
+    }
   }
-
-  const pathSearch = `${session.cwd ?? ''} ${session.filePath}`.toLowerCase()
-  if (parsed.pathTerms.some((term) => !pathSearch.includes(term))) {
-    return false
+  if (parsed.pathTerms.length > 0) {
+    const pathSearch = `${session.cwd ?? ''} ${session.filePath}`.toLowerCase()
+    if (parsed.pathTerms.some((term) => !pathSearch.includes(term))) {
+      return false
+    }
   }
 
   return true
 }
 
-function compareSessions(left: AiVaultSession, right: AiVaultSession, sort: AiVaultSort): number {
-  const leftValue = sort === 'created' ? left.createdAt : left.updatedAt
-  const rightValue = sort === 'created' ? right.createdAt : right.updatedAt
-  const leftTime = Date.parse(leftValue ?? left.modifiedAt)
-  const rightTime = Date.parse(rightValue ?? right.modifiedAt)
-  return rightTime - leftTime
+function sessionSortTime(session: AiVaultSession, sort: AiVaultSort): number {
+  const value = sort === 'created' ? session.createdAt : session.updatedAt
+  return Date.parse(value ?? session.modifiedAt)
 }
 
 function getGroupIdentity(
@@ -276,19 +281,15 @@ function getGroupIdentity(
   return { key: folderGroupKey(session.cwd), label: folderLabel(session.cwd) }
 }
 
-function isAiVaultSessionInWorkspacePath(workspacePath: string, sessionCwd: string): boolean {
-  if (isPathInsideOrEqual(workspacePath, sessionCwd)) {
-    return true
-  }
-
+function createAiVaultWorkspaceMatcher(workspacePath: string): (normalizedCwd: string) => boolean {
+  const matches = createNormalizedPathInsideOrEqualMatcher(workspacePath)
   const workspaceWslPath = parseWslUncPath(workspacePath)
   if (!workspaceWslPath) {
-    return false
+    return matches
   }
-
-  // WSL agent transcripts record Linux cwd values even when Orca stores the
-  // active worktree as a Windows UNC path.
-  return isPathInsideOrEqual(workspaceWslPath.linuxPath, sessionCwd)
+  // WSL transcripts record Linux cwd even when the workspace uses a UNC path.
+  const matchesLinux = createNormalizedPathInsideOrEqualMatcher(workspaceWslPath.linuxPath)
+  return (cwd) => matches(cwd) || matchesLinux(cwd)
 }
 
 function tokenizeQuery(query: string): string[] {