diff --git a/src/main/ai-vault/session-scanner-service-client-state.ts b/src/main/ai-vault/session-scanner-service-client-state.ts
index afa5b06e5cb..cbd778817dd 100644
--- a/src/main/ai-vault/session-scanner-service-client-state.ts
+++ b/src/main/ai-vault/session-scanner-service-client-state.ts
@@ -84,3 +84,25 @@ export type AiVaultServiceReadyWaiter = {
   reject: (error: Error) => void
   timer: NodeJS.Timeout
 }
+
+export class AiVaultServiceIdleRetirement {
+  private timer: NodeJS.Timeout | null = null
+
+  clear(): void {
+    if (this.timer) {
+      clearTimeout(this.timer)
+      this.timer = null
+    }
+  }
+
+  schedule(busy: boolean, timeoutMs: number, retire: () => void): void {
+    if (busy || this.timer) {
+      return
+    }
+    this.timer = setTimeout(() => {
+      this.timer = null
+      retire()
+    }, timeoutMs)
+    this.timer.unref?.()
+  }
+}
diff --git a/src/main/ai-vault/session-scanner-service-client.test.ts b/src/main/ai-vault/session-scanner-service-client.test.ts
index d10df1d01ba..2624baca06f 100644
--- a/src/main/ai-vault/session-scanner-service-client.test.ts
+++ b/src/main/ai-vault/session-scanner-service-client.test.ts
@@ -113,6 +113,44 @@ describe('AiVaultScannerServiceClient', () => {
     client.dispose()
   })
 
+  it('keeps invalidation-only children alive through acknowledgement, then retires them', async () => {
+    vi.useFakeTimers()
+    const children: AiVaultServiceTestChild[] = []
+    const client = new AiVaultScannerServiceClient({
+      processFactory: () => {
+        const child = new AiVaultServiceTestChild(12_345 + children.length)
+        children.push(child)
+        return child.asChildProcess()
+      },
+      init: { sessionParseCache: null },
+      idleTimeoutMs: 100
+    })
+
+    const first = client.request({ type: 'request', operation: 'titles', requests: [] })
+    readyAiVaultServiceChild(children[0]!)
+    await Promise.resolve()
+    children[0]!.emit('message', {
+      type: 'result',
+      id: aiVaultServiceRequestId(children[0]!, 'titles'),
+      operation: 'titles',
+      value: { titles: [] }
+    })
+    await first
+    vi.advanceTimersByTime(100)
+
+    const invalidation = client.invalidate(['/tmp/deleted.jsonl'])
+    readyAiVaultServiceChild(children[1]!)
+    await Promise.resolve()
+    vi.advanceTimersByTime(100)
+    expect(children[1]!.sent).not.toContainEqual({ type: 'shutdown' })
+    children[1]!.emit('message', { type: 'invalidated', generation: 1 })
+    await invalidation
+    vi.advanceTimersByTime(100)
+
+    expect(children[1]!.sent).toContainEqual({ type: 'shutdown' })
+    client.dispose()
+  })
+
   it('faults the child on malformed output without affecting later processes', async () => {
     const { child, client } = setup()
     const request = client.request({ type: 'request', operation: 'titles', requests: [] })
diff --git a/src/main/ai-vault/session-scanner-service-client.ts b/src/main/ai-vault/session-scanner-service-client.ts
index dc334e888e8..c79694cf888 100644
--- a/src/main/ai-vault/session-scanner-service-client.ts
+++ b/src/main/ai-vault/session-scanner-service-client.ts
@@ -6,6 +6,7 @@ import {
   AI_VAULT_SERVICE_MAX_CALLS,
   AI_VAULT_SERVICE_READY_TIMEOUT_MS,
   AI_VAULT_SERVICE_SCAN_TIMEOUT_MS,
+  AiVaultServiceIdleRetirement,
   armAiVaultServiceCancellationTimeout,
   clearAiVaultServiceCall,
   rejectAiVaultServiceCall,
@@ -35,7 +36,7 @@ export class AiVaultScannerServiceClient {
   private readonly invalidations = new Map<number, AiVaultServiceInvalidation>()
   private nextId = 1
   private invalidationGeneration = 0
-  private idleTimer: NodeJS.Timeout | null = null
+  private readonly idleRetirement = new AiVaultServiceIdleRetirement()
   private readonly restartPolicy = new AiVaultServiceRestartPolicy()
   private disposed = false
 
@@ -68,7 +69,7 @@ export class AiVaultScannerServiceClient {
         signal.addEventListener('abort', call.onAbort, { once: true })
       }
       this.queue.push(call)
-      this.clearIdleTimer()
+      this.idleRetirement.clear()
       this.pump()
     })
   }
@@ -77,12 +78,14 @@ export class AiVaultScannerServiceClient {
     if (paths.length === 0 || this.disposed) {
       return
     }
+    this.idleRetirement.clear()
     const child = await this.ensureChild()
     const generation = ++this.invalidationGeneration
     return new Promise<void>((resolve, reject) => {
       const timer = setTimeout(() => {
         this.invalidations.delete(generation)
         reject(new Error('AI Vault service cache invalidation timed out.'))
+        this.scheduleIdleIfNeeded()
       }, AI_VAULT_SERVICE_READY_TIMEOUT_MS)
       timer.unref?.()
       this.invalidations.set(generation, { resolve, reject, timer })
@@ -96,7 +99,7 @@ export class AiVaultScannerServiceClient {
     }
     this.disposed = true
     this.restartPolicy.dispose()
-    this.clearIdleTimer()
+    this.idleRetirement.clear()
     const error = new Error('AI Vault service client was disposed.')
     for (const call of [...this.active.values(), ...this.queue]) {
       rejectAiVaultServiceCall(call, error)
@@ -218,6 +221,7 @@ export class AiVaultScannerServiceClient {
         clearTimeout(pending.timer)
         this.invalidations.delete(message.generation)
         pending.resolve()
+        this.scheduleIdleIfNeeded()
       }
       return
     }
@@ -284,25 +288,15 @@ export class AiVaultScannerServiceClient {
   }
 
   private scheduleIdleIfNeeded(): void {
-    if (this.active.size > 0 || this.queue.length > 0 || !this.child || this.idleTimer) {
-      return
-    }
-    this.idleTimer = setTimeout(
-      () => this.retireChild(),
-      this.options.idleTimeoutMs ?? AI_VAULT_SERVICE_IDLE_TIMEOUT_MS
+    this.idleRetirement.schedule(
+      this.active.size > 0 || this.queue.length > 0 || this.invalidations.size > 0 || !this.child,
+      this.options.idleTimeoutMs ?? AI_VAULT_SERVICE_IDLE_TIMEOUT_MS,
+      () => this.retireChild()
     )
-    this.idleTimer.unref?.()
-  }
-
-  private clearIdleTimer(): void {
-    if (this.idleTimer) {
-      clearTimeout(this.idleTimer)
-      this.idleTimer = null
-    }
   }
 
   private retireChild(): void {
-    this.clearIdleTimer()
+    this.idleRetirement.clear()
     const child = this.child
     this.child = null
     if (!child) {
diff --git a/src/relay/ai-vault-service-client-state.ts b/src/relay/ai-vault-service-client-state.ts
index e38ddb2111c..91a4733b44e 100644
--- a/src/relay/ai-vault-service-client-state.ts
+++ b/src/relay/ai-vault-service-client-state.ts
@@ -12,6 +12,7 @@ export const RELAY_AI_VAULT_READY_TIMEOUT_MS = 5_000
 export const RELAY_AI_VAULT_SCAN_TIMEOUT_MS = 130_000
 export const RELAY_AI_VAULT_TITLE_TIMEOUT_MS = 15_000
 export const RELAY_AI_VAULT_MAX_CALLS = 16
+export const RELAY_AI_VAULT_IDLE_TIMEOUT_MS = 10 * 60_000
 
 export function relayAiVaultAbortError(): Error {
   const error = new Error('The operation was aborted.')
@@ -31,6 +32,27 @@ export function armRelayAiVaultCancellationTimeout(
   call.timer.unref?.()
 }
 
+export function settleRelayAiVaultServiceCall(
+  call: RelayAiVaultServiceCall,
+  value: Error | AiVaultListResult | AiVaultSessionTitlesResult
+): void {
+  if (call.settled) {
+    return
+  }
+  call.settled = true
+  if (call.timer) {
+    clearTimeout(call.timer)
+  }
+  if (call.signal && call.onAbort) {
+    call.signal.removeEventListener('abort', call.onAbort)
+  }
+  if (value instanceof Error) {
+    call.reject(value)
+  } else {
+    call.resolve(value)
+  }
+}
+
 export type RelayAiVaultServiceCall = {
   request: RelayAiVaultServiceRequest
   signal?: AbortSignal
@@ -57,4 +79,34 @@ export type RelayAiVaultServiceClientOptions = {
     hostPlatform: RemoteHostPlatform
   }
   now?: () => number
+  idleTimeoutMs?: number
+}
+
+export class RelayAiVaultIdleRetirement {
+  private timer: NodeJS.Timeout | null = null
+
+  clear(): void {
+    if (this.timer) {
+      clearTimeout(this.timer)
+      this.timer = null
+    }
+  }
+
+  schedule(busy: boolean, timeoutMs: number, retire: () => void): void {
+    if (busy || this.timer) {
+      return
+    }
+    this.timer = setTimeout(() => {
+      this.timer = null
+      retire()
+    }, timeoutMs)
+    this.timer.unref?.()
+  }
+}
+
+export function retireRelayAiVaultServiceChild(child: ChildProcess): void {
+  const timer = setTimeout(() => child.kill(), 2_000)
+  timer.unref?.()
+  child.once('exit', () => clearTimeout(timer))
+  child.send({ type: 'shutdown' }, () => undefined)
 }
diff --git a/src/relay/ai-vault-service-client.test.ts b/src/relay/ai-vault-service-client.test.ts
index 53399d6601d..15cc6eec0ae 100644
--- a/src/relay/ai-vault-service-client.test.ts
+++ b/src/relay/ai-vault-service-client.test.ts
@@ -7,7 +7,10 @@ import {
 import { RelayAiVaultServiceClient } from './ai-vault-service-client'
 import { relayAiVaultServiceEntryPath } from './ai-vault-service-spawn'
 
-function createClient(children: AiVaultServiceTestChild[]): RelayAiVaultServiceClient {
+function createClient(
+  children: AiVaultServiceTestChild[],
+  idleTimeoutMs?: number
+): RelayAiVaultServiceClient {
   return new RelayAiVaultServiceClient({
     init: {
       remoteHome: '/home/ada',
@@ -17,7 +20,8 @@ function createClient(children: AiVaultServiceTestChild[]): RelayAiVaultServiceC
       const child = new AiVaultServiceTestChild(20_000 + children.length)
       children.push(child)
       return child.asChildProcess()
-    }
+    },
+    idleTimeoutMs
   })
 }
 
@@ -122,6 +126,34 @@ describe('RelayAiVaultServiceClient', () => {
     await disposing
   })
 
+  it('retires the sidecar after the idle bound', async () => {
+    vi.useFakeTimers()
+    const children: AiVaultServiceTestChild[] = []
+    const client = createClient(children, 100)
+    const list = client.listSessions({})
+    const child = children[0]!
+    readyAiVaultServiceChild(child)
+    await Promise.resolve()
+    const request = child.sent.find(
+      (message) => (message as { operation?: string }).operation === 'list'
+    ) as { id: number }
+    child.emit('message', {
+      type: 'result',
+      id: request.id,
+      operation: 'list',
+      value: { sessions: [], issues: [], scannedAt: '2026-08-09T00:00:00.000Z' }
+    })
+    await list
+
+    vi.advanceTimersByTime(99)
+    expect(child.sent).not.toContainEqual({ type: 'shutdown' })
+    vi.advanceTimersByTime(1)
+    expect(child.sent).toContainEqual({ type: 'shutdown' })
+    vi.advanceTimersByTime(2_000)
+    expect(child.killed).toBe(true)
+    await client.dispose()
+  })
+
   it('resolves the sidecar beside each bundled relay', () => {
     expect(relayAiVaultServiceEntryPath('/opt/orca/relay')).toBe(
       '/opt/orca/relay/relay-ai-vault-service.js'
diff --git a/src/relay/ai-vault-service-client.ts b/src/relay/ai-vault-service-client.ts
index 3f1235612fe..df4ee5292d6 100644
--- a/src/relay/ai-vault-service-client.ts
+++ b/src/relay/ai-vault-service-client.ts
@@ -7,12 +7,16 @@ import type {
 import type { SshAiVaultRelayListParams } from '../shared/ssh-ai-vault-relay'
 import {
   RELAY_AI_VAULT_MAX_CALLS,
+  RELAY_AI_VAULT_IDLE_TIMEOUT_MS,
   RELAY_AI_VAULT_READY_TIMEOUT_MS,
   RELAY_AI_VAULT_SCAN_TIMEOUT_MS,
   RELAY_AI_VAULT_TITLE_TIMEOUT_MS,
   armRelayAiVaultCancellationTimeout,
   relayAiVaultAbortError,
   relayAiVaultError,
+  RelayAiVaultIdleRetirement,
+  retireRelayAiVaultServiceChild,
+  settleRelayAiVaultServiceCall,
   type RelayAiVaultServiceApi,
   type RelayAiVaultServiceCall,
   type RelayAiVaultServiceClientOptions
@@ -39,6 +43,7 @@ export class RelayAiVaultServiceClient implements RelayAiVaultServiceApi {
   private faults: number[] = []
   private circuitUntil = 0
   private restartTimer: NodeJS.Timeout | null = null
+  private readonly idleRetirement = new RelayAiVaultIdleRetirement()
   private disposed = false
 
   constructor(private readonly options: RelayAiVaultServiceClientOptions) {}
@@ -62,17 +67,18 @@ export class RelayAiVaultServiceClient implements RelayAiVaultServiceApi {
 
   async dispose(): Promise<void> {
     this.disposed = true
+    this.idleRetirement.clear()
     if (this.restartTimer) {
       clearTimeout(this.restartTimer)
       this.restartTimer = null
     }
     const error = new Error('Relay AI Vault service was disposed.')
     if (this.active) {
-      this.settle(this.active, error)
+      settleRelayAiVaultServiceCall(this.active, error)
       this.active = null
     }
     for (const call of this.queue.splice(0)) {
-      this.settle(call, error)
+      settleRelayAiVaultServiceCall(call, error)
     }
     const child = this.detachChild()
     if (!child) {
@@ -121,6 +127,7 @@ export class RelayAiVaultServiceClient implements RelayAiVaultServiceApi {
         signal.addEventListener('abort', call.onAbort, { once: true })
       }
       this.queue.push(call)
+      this.idleRetirement.clear()
       this.pump()
     })
   }
@@ -131,6 +138,7 @@ export class RelayAiVaultServiceClient implements RelayAiVaultServiceApi {
     }
     const call = this.queue.shift()
     if (!call) {
+      this.scheduleIdleIfNeeded()
       return
     }
     this.active = call
@@ -138,7 +146,7 @@ export class RelayAiVaultServiceClient implements RelayAiVaultServiceApi {
       (child) => this.sendCall(child, call),
       (error: Error) => {
         this.active = null
-        this.settle(call, error)
+        settleRelayAiVaultServiceCall(call, error)
         this.pump()
       }
     )
@@ -227,7 +235,10 @@ export class RelayAiVaultServiceClient implements RelayAiVaultServiceApi {
       return
     }
     this.active = null
-    this.settle(call, message.type === 'error' ? new Error(message.message) : message.value)
+    settleRelayAiVaultServiceCall(
+      call,
+      message.type === 'error' ? new Error(message.message) : message.value
+    )
     this.pump()
   }
 
@@ -235,13 +246,13 @@ export class RelayAiVaultServiceClient implements RelayAiVaultServiceApi {
     const index = this.queue.indexOf(call)
     if (index >= 0) {
       this.queue.splice(index, 1)
-      this.settle(call, relayAiVaultAbortError())
+      settleRelayAiVaultServiceCall(call, relayAiVaultAbortError())
       this.pump()
       return
     }
     if (this.active === call) {
       this.child?.send({ type: 'cancel', id: call.request.id })
-      this.settle(call, relayAiVaultAbortError())
+      settleRelayAiVaultServiceCall(call, relayAiVaultAbortError())
       armRelayAiVaultCancellationTimeout(call, () =>
         this.onFault(new Error('Relay AI Vault service did not cancel within 2000ms.'))
       )
@@ -252,12 +263,13 @@ export class RelayAiVaultServiceClient implements RelayAiVaultServiceApi {
     if (!this.child) {
       return
     }
+    this.idleRetirement.clear()
     this.detachChild()?.kill()
     this.readyReject?.(error)
     this.readyReject = null
     this.ready = null
     if (this.active) {
-      this.settle(this.active, error)
+      settleRelayAiVaultServiceCall(this.active, error)
       this.active = null
     }
     const now = (this.options.now ?? Date.now)()
@@ -275,31 +287,23 @@ export class RelayAiVaultServiceClient implements RelayAiVaultServiceApi {
     }
   }
 
-  private settle(
-    call: RelayAiVaultServiceCall,
-    value: Error | AiVaultListResult | AiVaultSessionTitlesResult
-  ): void {
-    if (call.settled) {
-      return
-    }
-    call.settled = true
-    if (call.timer) {
-      clearTimeout(call.timer)
-    }
-    if (call.signal && call.onAbort) {
-      call.signal.removeEventListener('abort', call.onAbort)
-    }
-    if (value instanceof Error) {
-      call.reject(value)
-    } else {
-      call.resolve(value)
-    }
-  }
-
   private detachChild(): ChildProcess | null {
     const child = this.child
     this.child = null
     child?.removeAllListeners()
     return child
   }
+
+  private scheduleIdleIfNeeded(): void {
+    this.idleRetirement.schedule(
+      Boolean(this.active || this.queue.length > 0 || !this.child),
+      this.options.idleTimeoutMs ?? RELAY_AI_VAULT_IDLE_TIMEOUT_MS,
+      () => {
+        const child = this.detachChild()
+        if (child) {
+          retireRelayAiVaultServiceChild(child)
+        }
+      }
+    )
+  }
 }