diff --git a/src/main/ai-vault/session-scanner-agent-parser.ts b/src/main/ai-vault/session-scanner-agent-parser.ts
index 385b29619..adfb2aa86 100644
--- a/src/main/ai-vault/session-scanner-agent-parser.ts
+++ b/src/main/ai-vault/session-scanner-agent-parser.ts
@@ -9,11 +9,8 @@ import {
 import { parseKimiSessionFile } from './session-scanner-kimi-parser'
 import { splitOpenCodeSqliteCandidate } from './session-scanner-opencode-sqlite-paths'
 import { parseOpenCodeSqliteSession } from './session-scanner-opencode-sqlite'
-import {
-  parseClaudeSessionFile,
-  parseCodexSessionFile,
-  parseGeminiSessionFile
-} from './session-scanner-primary-parsers'
+import { parseClaudeSessionFile, parseGeminiSessionFile } from './session-scanner-primary-parsers'
+import { parseCodexSessionFile } from './session-scanner-codex-parser'
 import {
   parseCopilotSessionFile,
   parseCursorSessionFile,
diff --git a/src/main/ai-vault/session-scanner-codex-parser.test.ts b/src/main/ai-vault/session-scanner-codex-parser.test.ts
new file mode 100644
index 000000000..19581fc87
--- /dev/null
+++ b/src/main/ai-vault/session-scanner-codex-parser.test.ts
@@ -0,0 +1,88 @@
+import { mkdir, mkdtemp, rm, stat, writeFile } from 'fs/promises'
+import { tmpdir } from 'os'
+import { dirname, join } from 'path'
+import { afterEach, describe, expect, it } from 'vitest'
+import { parseCodexSessionFile } from './session-scanner-codex-parser'
+
+let tempRoots: string[] = []
+
+afterEach(async () => {
+  await Promise.all(tempRoots.map((root) => rm(root, { recursive: true, force: true })))
+  tempRoots = []
+})
+
+function jsonLines(records: unknown[]): string {
+  return records.map((record) => JSON.stringify(record)).join('\n')
+}
+
+describe('parseCodexSessionFile', () => {
+  it('does not double-count usage when token count formats switch', async () => {
+    const root = await mkdtemp(join(tmpdir(), 'orca-ai-vault-codex-token-switch-'))
+    tempRoots.push(root)
+    const sessionPath = join(root, 'sessions', '2026', '06', '18', 'rollout-token-switch.jsonl')
+    await mkdir(dirname(sessionPath), { recursive: true })
+
+    await writeFile(
+      sessionPath,
+      jsonLines([
+        {
+          timestamp: '2026-06-18T10:00:00.000Z',
+          type: 'session_meta',
+          payload: { id: 'token-format-switch', cwd: '/repo/app' }
+        },
+        {
+          timestamp: '2026-06-18T10:00:01.000Z',
+          type: 'response_item',
+          payload: {
+            type: 'message',
+            role: 'user',
+            content: [{ type: 'text', text: 'Measure Codex token totals' }]
+          }
+        },
+        {
+          timestamp: '2026-06-18T10:00:02.000Z',
+          type: 'event_msg',
+          payload: {
+            type: 'token_count',
+            info: {
+              last_token_usage: {
+                input_tokens: 70,
+                cached_input_tokens: 20,
+                output_tokens: 30,
+                total_tokens: 100
+              }
+            }
+          }
+        },
+        {
+          timestamp: '2026-06-18T10:00:03.000Z',
+          type: 'event_msg',
+          payload: {
+            type: 'token_count',
+            info: {
+              total_token_usage: {
+                input_tokens: 90,
+                cached_input_tokens: 25,
+                output_tokens: 60,
+                total_tokens: 150
+              }
+            }
+          }
+        }
+      ])
+    )
+
+    const sessionStat = await stat(sessionPath)
+    const session = await parseCodexSessionFile(
+      {
+        path: sessionPath,
+        mtimeMs: sessionStat.mtimeMs,
+        modifiedAt: sessionStat.mtime.toISOString()
+      },
+      'darwin',
+      root
+    )
+
+    expect(session?.totalTokens).toBe(150)
+  })
+})
diff --git a/src/main/ai-vault/session-scanner-codex-parser.ts b/src/main/ai-vault/session-scanner-codex-parser.ts
new file mode 100644
index 000000000..5435b2eaf
--- /dev/null
+++ b/src/main/ai-vault/session-scanner-codex-parser.ts
@@ -0,0 +1,273 @@
+import { createReadStream } from 'fs'
+import { stat } from 'fs/promises'
+import { basename, dirname, join } from 'path'
+import { createInterface } from 'readline'
+import type { AiVaultSession } from '../../shared/ai-vault-types'
+import {
+  addPreviewContent,
+  createAccumulator,
+  finalizeSession,
+  sessionIdFromFileName,
+  updateTimeline
+} from './session-scanner-accumulator'
+import type { CodexUsageSnapshot, FileWithMtime } from './session-scanner-types'
+import {
+  asRecord,
+  extractContentText,
+  extractGitBranch,
+  extractModel,
+  extractString,
+  normalizeCodexUsage,
+  normalizeTitleText,
+  parseJsonObject,
+  subtractCodexUsage
+} from './session-scanner-values'
+
+const CODEX_SESSION_INDEX_FILE = 'session_index.jsonl'
+
+type CodexSessionIndexTitleCacheEntry = {
+  signature: string
+  titles: Map<string, string>
+}
+
+const codexSessionIndexTitleCache = new Map<string, Promise<CodexSessionIndexTitleCacheEntry>>()
+
+export async function parseCodexSessionFile(
+  file: FileWithMtime,
+  platform: NodeJS.Platform = process.platform,
+  codexHome: string | null = null
+): Promise<AiVaultSession | null> {
+  const accumulator = createAccumulator({
+    agent: 'codex',
+    file,
+    sessionId: sessionIdFromFileName(file.path)
+  })
+  let previousTotals: CodexUsageSnapshot | null = null
+
+  const lines = createInterface({
+    input: createReadStream(file.path, { encoding: 'utf-8' }),
+    crlfDelay: Infinity
+  })
+
+  for await (const line of lines) {
+    const record = parseJsonObject(line)
+    if (!record) {
+      continue
+    }
+
+    updateTimeline(accumulator, extractString(record.timestamp))
+
+    const payload = asRecord(record.payload)
+    if (record.type === 'session_meta' && payload) {
+      if (isCodexWorkerSession(payload)) {
+        // Why: Codex writes internal worker/sub-agent transcripts into the same
+        // history tree; AI Vault should show user-started sessions only.
+        return null
+      }
+      const sessionId = extractString(payload.id)
+      if (sessionId) {
+        accumulator.sessionId = sessionId
+      }
+      const indexedTitle =
+        extractCodexSessionMetadataTitle(payload) ??
+        (await readCodexSessionIndexTitle(file.path, codexHome, accumulator.sessionId))
+      if (indexedTitle) {
+        accumulator.title = indexedTitle
+      }
+      const cwd = extractString(payload.cwd)
+      if (cwd) {
+        accumulator.cwd = cwd
+      }
+      accumulator.branch = extractGitBranch(payload.git) ?? accumulator.branch
+      continue
+    }
+
+    if (record.type === 'turn_context' && payload) {
+      const cwd = extractString(payload.cwd)
+      if (cwd) {
+        accumulator.cwd = cwd
+      }
+      const model = extractModel(payload)
+      if (model) {
+        accumulator.model = model
+      }
+      continue
+    }
+
+    if (!payload) {
+      continue
+    }
+
+    if (record.type === 'response_item' && payload.type === 'message') {
+      accumulator.messageCount++
+      if (payload.role === 'user' && !accumulator.title) {
+        accumulator.title = extractContentText(payload.content)
+      }
+      addPreviewContent(
+        accumulator,
+        payload.role === 'assistant' ? 'assistant' : payload.role === 'user' ? 'user' : 'unknown',
+        payload.content,
+        record.timestamp
+      )
+      continue
+    }
+
+    if (record.type !== 'event_msg') {
+      continue
+    }
+
+    if (payload.type === 'user_message') {
+      accumulator.messageCount++
+      if (!accumulator.title) {
+        accumulator.title = extractContentText(payload.message)
+      }
+      addPreviewContent(accumulator, 'user', payload.message, record.timestamp)
+      continue
+    }
+
+    if (payload.type === 'agent_message') {
+      accumulator.messageCount++
+      addPreviewContent(accumulator, 'assistant', payload.message, record.timestamp)
+      continue
+    }
+
+    if (payload.type !== 'token_count') {
+      continue
+    }
+
+    const info = asRecord(payload.info)
+    if (!info) {
+      continue
+    }
+    const totalUsage = normalizeCodexUsage(info.total_token_usage)
+    const lastUsage = normalizeCodexUsage(info.last_token_usage)
+    let delta: CodexUsageSnapshot | null = null
+    if (totalUsage) {
+      delta = subtractCodexUsage(totalUsage, previousTotals)
+      previousTotals = totalUsage
+    } else if (lastUsage) {
+      delta = lastUsage
+      previousTotals = previousTotals ? addCodexUsage(previousTotals, lastUsage) : lastUsage
+    }
+    if (delta) {
+      accumulator.totalTokens += delta.totalTokens
+    }
+    const model = extractModel(payload)
+    if (model) {
+      accumulator.model = model
+    }
+  }
+
+  return finalizeSession(accumulator, platform, { codexHome })
+}
+
+function addCodexUsage(
+  base: CodexUsageSnapshot,
+  increment: CodexUsageSnapshot
+): CodexUsageSnapshot {
+  return {
+    inputTokens: base.inputTokens + increment.inputTokens,
+    cachedInputTokens: base.cachedInputTokens + increment.cachedInputTokens,
+    outputTokens: base.outputTokens + increment.outputTokens,
+    reasoningOutputTokens: base.reasoningOutputTokens + increment.reasoningOutputTokens,
+    totalTokens: base.totalTokens + increment.totalTokens
+  }
+}
+
+function extractCodexThreadSource(payload: Record<string, unknown>): string | null {
+  return extractString(payload.thread_source) ?? extractString(payload.threadSource)
+}
+
+function isCodexWorkerSession(payload: Record<string, unknown>): boolean {
+  const threadSource = extractCodexThreadSource(payload)
+  if (threadSource) {
+    return threadSource.toLowerCase() !== 'user'
+  }
+
+  const source = asRecord(payload.source)
+  return Boolean(asRecord(source?.subagent))
+}
+
+function extractCodexSessionMetadataTitle(payload: Record<string, unknown>): string | null {
+  return (
+    normalizeTitleText(extractString(payload.title) ?? '') ??
+    normalizeTitleText(extractString(payload.thread_name) ?? '') ??
+    normalizeTitleText(extractString(payload.threadName) ?? '')
+  )
+}
+
+async function readCodexSessionIndexTitle(
+  sessionFilePath: string,
+  codexHome: string | null,
+  sessionId: string
+): Promise<string | null> {
+  const resolvedCodexHome = codexHome ?? codexHomeFromSessionFilePath(sessionFilePath)
+  if (!resolvedCodexHome) {
+    return null
+  }
+  const titleBySessionId = await readCodexSessionIndexTitles(resolvedCodexHome)
+  return titleBySessionId.get(sessionId) ?? null
+}
+
+function codexHomeFromSessionFilePath(sessionFilePath: string): string | null {
+  let currentDir = dirname(sessionFilePath)
+  while (currentDir && dirname(currentDir) !== currentDir) {
+    if (basename(currentDir) === 'sessions') {
+      return dirname(currentDir)
+    }
+    currentDir = dirname(currentDir)
+  }
+  return null
+}
+
+async function readCodexSessionIndexTitles(codexHome: string): Promise<Map<string, string>> {
+  const indexPath = join(codexHome, CODEX_SESSION_INDEX_FILE)
+  let signature: string
+  try {
+    const indexStat = await stat(indexPath)
+    signature = `${indexStat.size}:${indexStat.mtimeMs}`
+  } catch {
+    return new Map()
+  }
+
+  const cached = codexSessionIndexTitleCache.get(codexHome)
+  if (cached) {
+    const entry = await cached
+    if (entry.signature === signature) {
+      return entry.titles
+    }
+  }
+
+  const pending = readCodexSessionIndexTitlesFromDisk(indexPath).then((titles) => ({
+    signature,
+    titles
+  }))
+  codexSessionIndexTitleCache.set(codexHome, pending)
+  return (await pending).titles
+}
+
+async function readCodexSessionIndexTitlesFromDisk(
+  indexPath: string
+): Promise<Map<string, string>> {
+  const titleBySessionId = new Map<string, string>()
+  try {
+    const lines = createInterface({
+      input: createReadStream(indexPath, { encoding: 'utf-8' }),
+      crlfDelay: Infinity
+    })
+    for await (const line of lines) {
+      const record = parseJsonObject(line)
+      if (!record) {
+        continue
+      }
+      const sessionId = extractString(record.id)
+      const title = normalizeTitleText(extractString(record.thread_name) ?? '')
+      if (sessionId && title) {
+        titleBySessionId.set(sessionId, title)
+      }
+    }
+  } catch {
+    // Codex creates the index opportunistically; older homes may only have raw transcripts.
+  }
+  return titleBySessionId
+}
diff --git a/src/main/ai-vault/session-scanner-primary-parsers.ts b/src/main/ai-vault/session-scanner-primary-parsers.ts
index fced9ab1f..dc062f5ab 100644
--- a/src/main/ai-vault/session-scanner-primary-parsers.ts
+++ b/src/main/ai-vault/session-scanner-primary-parsers.ts
@@ -2,7 +2,7 @@ import { createReadStream } from 'fs'
 import { readFile } from 'fs/promises'
 import { createInterface } from 'readline'
 import type { AiVaultSession } from '../../shared/ai-vault-types'
-import type { CodexUsageSnapshot, FileWithMtime, SessionAccumulator } from './session-scanner-types'
+import type { FileWithMtime, SessionAccumulator } from './session-scanner-types'
 import {
   addPreviewContent,
   createAccumulator,
@@ -16,14 +16,10 @@ import {
   asRecord,
   claudeUsageTotal,
   extractContentText,
-  extractGitBranch,
   extractMessageText,
-  extractModel,
   extractString,
-  normalizeCodexUsage,
   normalizeTitleText,
   parseJsonObject,
-  subtractCodexUsage,
   tokenTotal
 } from './session-scanner-values'
 
@@ -99,139 +95,6 @@ export async function parseClaudeSessionFile(
   return finalizeSession(accumulator, platform)
 }
 
-export async function parseCodexSessionFile(
-  file: FileWithMtime,
-  platform: NodeJS.Platform = process.platform,
-  codexHome: string | null = null
-): Promise<AiVaultSession | null> {
-  const accumulator = createAccumulator({
-    agent: 'codex',
-    file,
-    sessionId: sessionIdFromFileName(file.path)
-  })
-  let previousTotals: CodexUsageSnapshot | null = null
-
-  const lines = createInterface({
-    input: createReadStream(file.path, { encoding: 'utf-8' }),
-    crlfDelay: Infinity
-  })
-
-  for await (const line of lines) {
-    const record = parseJsonObject(line)
-    if (!record) {
-      continue
-    }
-
-    updateTimeline(accumulator, extractString(record.timestamp))
-
-    const payload = asRecord(record.payload)
-    if (record.type === 'session_meta' && payload) {
-      if (isCodexWorkerSession(payload)) {
-        // Why: Codex writes internal worker/sub-agent transcripts into the same
-        // history tree; AI Vault should show user-started sessions only.
-        return null
-      }
-      const sessionId = extractString(payload.id)
-      if (sessionId) {
-        accumulator.sessionId = sessionId
-      }
-      const cwd = extractString(payload.cwd)
-      if (cwd) {
-        accumulator.cwd = cwd
-      }
-      accumulator.branch = extractGitBranch(payload.git) ?? accumulator.branch
-      continue
-    }
-
-    if (record.type === 'turn_context' && payload) {
-      const cwd = extractString(payload.cwd)
-      if (cwd) {
-        accumulator.cwd = cwd
-      }
-      const model = extractModel(payload)
-      if (model) {
-        accumulator.model = model
-      }
-      continue
-    }
-
-    if (!payload) {
-      continue
-    }
-
-    if (record.type === 'response_item' && payload.type === 'message') {
-      accumulator.messageCount++
-      if (payload.role === 'user' && !accumulator.title) {
-        accumulator.title = extractContentText(payload.content)
-      }
-      addPreviewContent(
-        accumulator,
-        payload.role === 'assistant' ? 'assistant' : payload.role === 'user' ? 'user' : 'unknown',
-        payload.content,
-        record.timestamp
-      )
-      continue
-    }
-
-    if (record.type !== 'event_msg') {
-      continue
-    }
-
-    if (payload.type === 'user_message') {
-      accumulator.messageCount++
-      if (!accumulator.title) {
-        accumulator.title = extractContentText(payload.message)
-      }
-      addPreviewContent(accumulator, 'user', payload.message, record.timestamp)
-      continue
-    }
-
-    if (payload.type === 'agent_message') {
-      accumulator.messageCount++
-      addPreviewContent(accumulator, 'assistant', payload.message, record.timestamp)
-      continue
-    }
-
-    if (payload.type !== 'token_count') {
-      continue
-    }
-
-    const info = asRecord(payload.info)
-    if (!info) {
-      continue
-    }
-    const totalUsage = normalizeCodexUsage(info.total_token_usage)
-    const lastUsage = normalizeCodexUsage(info.last_token_usage)
-    const delta = totalUsage ? subtractCodexUsage(totalUsage, previousTotals) : lastUsage
-    if (totalUsage) {
-      previousTotals = totalUsage
-    }
-    if (delta) {
-      accumulator.totalTokens += delta.totalTokens
-    }
-    const model = extractModel(payload)
-    if (model) {
-      accumulator.model = model
-    }
-  }
-
-  return finalizeSession(accumulator, platform, { codexHome })
-}
-
-function extractCodexThreadSource(payload: Record<string, unknown>): string | null {
-  return extractString(payload.thread_source) ?? extractString(payload.threadSource)
-}
-
-function isCodexWorkerSession(payload: Record<string, unknown>): boolean {
-  const threadSource = extractCodexThreadSource(payload)
-  if (threadSource) {
-    return threadSource.toLowerCase() !== 'user'
-  }
-
-  const source = asRecord(payload.source)
-  return Boolean(asRecord(source?.subagent))
-}
-
 export async function parseGeminiSessionFile(
   file: FileWithMtime,
   platform: NodeJS.Platform = process.platform
diff --git a/src/main/ai-vault/session-scanner-text-normalization.ts b/src/main/ai-vault/session-scanner-text-normalization.ts
index 8bd58ad64..88eae73eb 100644
--- a/src/main/ai-vault/session-scanner-text-normalization.ts
+++ b/src/main/ai-vault/session-scanner-text-normalization.ts
@@ -5,7 +5,7 @@ const HIDDEN_BLOCK_CLOSE_SCAN_LIMIT = 256 * 1024
 const HIDDEN_BLOCK_OPEN_TAG_SCAN_LIMIT = 512
 const FIELD_BLANK_SCAN_LIMIT = 1024
 
-const AGENTS_INSTRUCTIONS_PREFIX = '# AGENTS.md instructions for'
+const AGENTS_INSTRUCTIONS_PREFIX = '# AGENTS.md instructions'
 const XML_INSTRUCTIONS_PREFIX = '<INSTRUCTIONS>'
 
 const HIDDEN_TEXT_BLOCKS = [
diff --git a/src/main/ai-vault/session-scanner.test.ts b/src/main/ai-vault/session-scanner.test.ts
index d8afc36b7..a4c5cf654 100644
--- a/src/main/ai-vault/session-scanner.test.ts
+++ b/src/main/ai-vault/session-scanner.test.ts
@@ -113,7 +113,7 @@ describe('scanAiVaultSessions', () => {
             type: 'message',
             role: 'user',
             content: [
-              { type: 'text', text: '# AGENTS.md instructions for /repo/app <INSTRUCTIONS>' }
+              { type: 'text', text: '# AGENTS.md instructions\n\n<INSTRUCTIONS>repo policy' }
             ]
           }
         }),
@@ -165,6 +165,15 @@ describe('scanAiVaultSessions', () => {
         })
       ].join('\n')
     )
+    await writeFile(
+      join(root, 'session_index.jsonl'),
+      jsonLines([
+        {
+          id: '019f0000-1111-7222-8333-444444444444',
+          thread_name: 'Indexed Codex resume picker title'
+        }
+      ])
+    )
 
     const result = await scanAiVaultSessions({
       ...roots,
@@ -174,7 +183,7 @@ describe('scanAiVaultSessions', () => {
     expect(result.issues).toEqual([])
     expect(result.sessions).toHaveLength(2)
     expect(result.sessions.map((session) => session.title).sort()).toEqual([
-      'Fix the resume picker filters',
+      'Indexed Codex resume picker title',
       'Vault polish pass'
     ])