diff --git a/src/main/ai-vault-search/session-search-store-chunking.test.ts b/src/main/ai-vault-search/session-search-store-chunking.test.ts
new file mode 100644
index 00000000000..bfe426e4c33
--- /dev/null
+++ b/src/main/ai-vault-search/session-search-store-chunking.test.ts
@@ -0,0 +1,135 @@
+import { mkdtemp, rm, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, beforeEach, describe, expect, it } from 'vitest'
+import { resetSessionParseCacheForTests } from '../ai-vault/session-scanner-parse-cache'
+import { registerSessionSearchIndexSink } from '../ai-vault/session-search-capture'
+import { SessionSearchStore } from './session-search-store'
+import {
+  assistantRecord,
+  CLAUDE_SESSION_ID as SESSION_ID,
+  CODEX_ROLLOUT_FILE,
+  CODEX_SESSION_ID,
+  codexRolloutLines,
+  parseTranscript,
+  userRecord
+} from './session-search-transcript-fixtures'
+
+let tempRoots: string[] = []
+let store: SessionSearchStore
+
+beforeEach(async () => {
+  resetSessionParseCacheForTests()
+  const root = await makeTempDir()
+  store = new SessionSearchStore(join(root, 'index.sqlite'), (error) => {
+    throw error
+  })
+  registerSessionSearchIndexSink(store)
+})
+
+afterEach(async () => {
+  registerSessionSearchIndexSink(null)
+  store.close()
+  await Promise.all(tempRoots.map((root) => rm(root, { recursive: true, force: true })))
+  tempRoots = []
+})
+
+async function makeTempDir(): Promise<string> {
+  const root = await mkdtemp(join(tmpdir(), 'orca-session-chunking-'))
+  tempRoots.push(root)
+  return root
+}
+
+/** `lines` × 100 chars each, with `markers` (word, char offset) planted in place. */
+function paddedText(lines: number, markers: { word: string; offset: number }[]): string {
+  const out: string[] = []
+  for (let index = 0; index < lines; index += 1) {
+    const marker = markers.find((entry) => Math.floor(entry.offset / 100) === index)
+    const body = marker ? `${marker.word} ` : ''
+    out.push(`${body}line${index} ${'padding '.repeat(20)}`.slice(0, 99))
+  }
+  return `${out.join('\n')}\n`
+}
+
+describe('session search chunking and coverage', () => {
+  it('splits a 30 KB assistant message into rows that all stay on one session', async () => {
+    const root = await makeTempDir()
+    const path = join(root, `${SESSION_ID}.jsonl`)
+    // 300 × 100-char lines: chunks land on the 8000-char line boundaries exactly.
+    const long = paddedText(300, [{ word: 'zygomorphic', offset: 26_500 }])
+    expect(long.length).toBe(30_000)
+    await writeFile(
+      path,
+      `${[userRecord(0, 'summarize the log'), assistantRecord(1, long)].join('\n')}\n`
+    )
+    await parseTranscript(path)
+
+    // 8000 + 8000 + 8000 + 6000, plus the one user message.
+    expect(store.coverage()).toMatchObject({ sessionsIndexed: 1, messagesIndexed: 5 })
+    // A term in the last 5 KB is only reachable because the tail is its own row.
+    const tail = store.search({ query: 'zygomorphic' })
+    expect(tail.hits).toHaveLength(1)
+    expect(tail.hits[0]).toMatchObject({ sessionId: SESSION_ID, evidence: { role: 'assistant' } })
+  })
+
+  it('caps a 100 KB tool output at 3 KB', async () => {
+    const root = await makeTempDir()
+    const path = join(root, `${SESSION_ID}.jsonl`)
+    const output = paddedText(1000, [
+      { word: 'earlyneedle', offset: 2000 },
+      { word: 'lateneedle', offset: 4000 }
+    ])
+    expect(output.length).toBe(100_000)
+    await writeFile(
+      path,
+      `${[
+        userRecord(0, 'run the suite'),
+        userRecord(1, [{ type: 'tool_result', tool_use_id: 'toolu_1', content: output }])
+      ].join('\n')}\n`
+    )
+    await parseTranscript(path)
+
+    expect(store.search({ query: 'earlyneedle' }).hits).toHaveLength(1)
+    expect(store.search({ query: 'lateneedle' }).hits).toHaveLength(0)
+    // One user row plus one tool row: the cap lands inside a single chunk.
+    expect(store.coverage().messagesIndexed).toBe(2)
+  })
+
+  it('counts coverage per provider and indexes Codex CommandExecution as tool rows', async () => {
+    const root = await makeTempDir()
+    const claudePath = join(root, `${SESSION_ID}.jsonl`)
+    await writeFile(claudePath, `${userRecord(0, 'claude side question')}\n`)
+    await parseTranscript(claudePath)
+
+    const codexPath = join(root, CODEX_ROLLOUT_FILE)
+    await writeFile(
+      codexPath,
+      `${codexRolloutLines(
+        ['pnpm', 'test', 'src/main/ai-vault-search'],
+        'FAIL src/main/ai-vault-search/quixotic.test.ts',
+        'codex side question'
+      ).join('\n')}\n`
+    )
+    await parseTranscript(codexPath, 'codex')
+
+    expect(store.coverage()).toMatchObject({
+      sessionsIndexed: 2,
+      // claude: 1 prompt. codex: 1 prompt + command + aggregated output.
+      messagesIndexed: 4,
+      providers: [
+        { agent: 'claude', sessionsIndexed: 1, messagesIndexed: 1 },
+        { agent: 'codex', sessionsIndexed: 1, messagesIndexed: 3 }
+      ]
+    })
+
+    const command = store.search({ query: 'pnpm test src/main/ai-vault-search' })
+    expect(command.hits).toHaveLength(1)
+    expect(command.hits[0]).toMatchObject({
+      agent: 'codex',
+      sessionId: CODEX_SESSION_ID,
+      evidence: { role: 'tool' }
+    })
+    const output = store.search({ query: 'quixotic' })
+    expect(output.hits[0]).toMatchObject({ agent: 'codex', evidence: { role: 'tool' } })
+  })
+})
diff --git a/src/main/ai-vault-search/session-search-transcript-fixtures.ts b/src/main/ai-vault-search/session-search-transcript-fixtures.ts
index e59ae113014..a6be36a9408 100644
--- a/src/main/ai-vault-search/session-search-transcript-fixtures.ts
+++ b/src/main/ai-vault-search/session-search-transcript-fixtures.ts
@@ -76,3 +76,31 @@ export async function parseTranscript(
   )
   return { stats }
 }
+
+function codexLine(record: Record<string, unknown>): string {
+  return JSON.stringify(record)
+}
+
+/** Minimal Codex rollout: meta, one user message, one completed shell command. */
+export function codexRolloutLines(command: string[], output: string, prompt: string): string[] {
+  return [
+    codexLine({
+      timestamp: recordTimestamp(0),
+      type: 'session_meta',
+      payload: { id: CODEX_SESSION_ID, cwd: '/repo/app', git: { branch: 'main' } }
+    }),
+    codexLine({
+      timestamp: recordTimestamp(1),
+      type: 'response_item',
+      payload: { type: 'message', role: 'user', content: prompt }
+    }),
+    codexLine({
+      timestamp: recordTimestamp(2),
+      type: 'event_msg',
+      payload: {
+        type: 'item_completed',
+        item: { type: 'CommandExecution', command, aggregated_output: output }
+      }
+    })
+  ]
+}