diff --git a/src/main/daemon/daemon-audit-eligibility-event.test.ts b/src/main/daemon/daemon-audit-eligibility-event.test.ts
index b17b5ba3892..ee4aba60865 100644
--- a/src/main/daemon/daemon-audit-eligibility-event.test.ts
+++ b/src/main/daemon/daemon-audit-eligibility-event.test.ts
@@ -1,11 +1,20 @@
-import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { mkdtempSync, rmSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import { validate } from '../telemetry/validator'
 import { recordAuthenticatedInventory, type DaemonAuditContext } from './daemon-audit-classifier'
+import { DaemonPtyAdapter } from './daemon-pty-adapter'
+import { DaemonServer } from './daemon-server'
+import { getDaemonSocketPath } from './daemon-spawner'
 
 const { trackMock } = vi.hoisted(() => ({ trackMock: vi.fn() }))
 vi.mock('../telemetry/client', () => ({ track: trackMock }))
 
-import { trackDaemonAuditEligibility } from './daemon-audit-eligibility-event'
+import {
+  createDaemonAuditEligibilityTracker,
+  trackDaemonAuditEligibility
+} from './daemon-audit-eligibility-event'
 
 const context: DaemonAuditContext = {
   protocolGeneration: 23,
@@ -48,4 +57,76 @@ describe('daemon audit eligibility telemetry', () => {
       trackDaemonAuditEligibility(recordAuthenticatedInventory(context, null))
     ).not.toThrow()
   })
+
+  it('collapses repeated identical observations into one heartbeat per window', () => {
+    let nowMs = 1_700_000_000_000
+    const trackEligibility = createDaemonAuditEligibilityTracker(() => nowMs)
+
+    for (let index = 0; index < 60; index += 1) {
+      nowMs += 1_000
+      trackEligibility(recordAuthenticatedInventory(context, null))
+    }
+
+    expect(trackMock).toHaveBeenCalledOnce()
+
+    nowMs += 5 * 60_000
+    trackEligibility(recordAuthenticatedInventory(context, null))
+    expect(trackMock).toHaveBeenCalledTimes(2)
+  })
+
+  it('emits immediately when the observation changes', () => {
+    let nowMs = 1_700_000_000_000
+    const trackEligibility = createDaemonAuditEligibilityTracker(() => nowMs)
+
+    trackEligibility(recordAuthenticatedInventory(context, null))
+    nowMs += 1_000
+    trackEligibility(
+      recordAuthenticatedInventory(context, {
+        identity: { pid: 42, startedAtMs: nowMs, launchNonce: 'launch-a' }
+      })
+    )
+
+    expect(trackMock).toHaveBeenCalledTimes(2)
+    expect(trackMock.mock.calls[1][1]).toMatchObject({ exact_incarnation: 'endpoint-identity' })
+  })
+})
+
+describe('daemon audit eligibility inventory volume', () => {
+  let dir: string
+  let socketPath: string
+  let tokenPath: string
+  let server: DaemonServer
+  let adapter: DaemonPtyAdapter
+
+  beforeEach(() => {
+    dir = mkdtempSync(join(tmpdir(), 'daemon-audit-eligibility-'))
+    socketPath = getDaemonSocketPath(dir)
+    tokenPath = join(dir, 'daemon.token')
+  })
+
+  afterEach(async () => {
+    adapter?.dispose()
+    await server?.shutdown()
+    rmSync(dir, { recursive: true, force: true })
+  })
+
+  it('does not emit one eligibility event per successful inventory', async () => {
+    server = new DaemonServer({
+      socketPath,
+      tokenPath,
+      spawnSubprocess: () => {
+        throw new Error('Test must not create a PTY')
+      }
+    })
+    await server.start()
+    adapter = new DaemonPtyAdapter({ socketPath, tokenPath })
+
+    for (let index = 0; index < 40; index += 1) {
+      await adapter.listProcesses()
+    }
+
+    expect(
+      trackMock.mock.calls.filter(([name]) => name === 'daemon_audit_eligibility')
+    ).toHaveLength(1)
+  })
 })
diff --git a/src/main/daemon/daemon-audit-eligibility-event.ts b/src/main/daemon/daemon-audit-eligibility-event.ts
index 0511f7a384a..cd600a3b86a 100644
--- a/src/main/daemon/daemon-audit-eligibility-event.ts
+++ b/src/main/daemon/daemon-audit-eligibility-event.ts
@@ -1,29 +1,61 @@
 import { track } from '../telemetry/client'
+import type { EventProps } from '../../shared/telemetry-events'
 import type { DaemonAuditObservation } from './daemon-audit-classifier'
 
+// Why: a steady daemon repeats a byte-identical observation on every listProcesses call, so
+// repeats are re-sent only as an occasional heartbeat — the shared per-session telemetry
+// ceiling is 1,000 events for the whole app and audit data must not crowd it out.
+const REPEATED_OBSERVATION_INTERVAL_MS = 5 * 60_000
+
 export function trackDaemonAuditEligibility(observation: DaemonAuditObservation): void {
   try {
-    track('daemon_audit_eligibility', {
-      state: observation.state,
-      reason: observation.reason,
-      trigger: observation.trigger,
-      evidence_sources: [...observation.evidenceSources],
-      protocol_generation: observation.context.protocolGeneration,
-      provider: observation.context.provider,
-      endpoint_kind: observation.context.endpointKind,
-      profile_scope: observation.context.profileScope ? 'configured' : 'unspecified',
-      exact_incarnation: exactIncarnationKind(observation),
-      reachability: observation.reachability,
-      inventory_authority: observation.inventoryAuthority,
-      process_liveness: observation.processLiveness,
-      process_reason: observation.processReason,
-      endpoint_state: observation.endpointState
-    })
+    track('daemon_audit_eligibility', auditEligibilityProperties(observation))
   } catch {
     // Audit telemetry cannot affect daemon availability.
   }
 }
 
+export function createDaemonAuditEligibilityTracker(
+  now: () => number = Date.now
+): (observation: DaemonAuditObservation) => void {
+  let lastProperties: string | null = null
+  let lastTrackedAtMs = 0
+  return (observation) => {
+    const properties = JSON.stringify(auditEligibilityProperties(observation))
+    const observedAtMs = now()
+    if (
+      properties === lastProperties &&
+      observedAtMs - lastTrackedAtMs < REPEATED_OBSERVATION_INTERVAL_MS
+    ) {
+      return
+    }
+    lastProperties = properties
+    lastTrackedAtMs = observedAtMs
+    trackDaemonAuditEligibility(observation)
+  }
+}
+
+function auditEligibilityProperties(
+  observation: DaemonAuditObservation
+): EventProps<'daemon_audit_eligibility'> {
+  return {
+    state: observation.state,
+    reason: observation.reason,
+    trigger: observation.trigger,
+    evidence_sources: [...observation.evidenceSources],
+    protocol_generation: observation.context.protocolGeneration,
+    provider: observation.context.provider,
+    endpoint_kind: observation.context.endpointKind,
+    profile_scope: observation.context.profileScope ? 'configured' : 'unspecified',
+    exact_incarnation: exactIncarnationKind(observation),
+    reachability: observation.reachability,
+    inventory_authority: observation.inventoryAuthority,
+    process_liveness: observation.processLiveness,
+    process_reason: observation.processReason,
+    endpoint_state: observation.endpointState
+  }
+}
+
 function exactIncarnationKind(
   observation: DaemonAuditObservation
 ): 'endpoint-identity' | 'endpoint-identity-linux-ticks' | 'unavailable' {
diff --git a/src/main/daemon/daemon-incarnation-evidence-main-thread.test.ts b/src/main/daemon/daemon-incarnation-evidence-main-thread.test.ts
new file mode 100644
index 00000000000..6df2a5ca33c
--- /dev/null
+++ b/src/main/daemon/daemon-incarnation-evidence-main-thread.test.ts
@@ -0,0 +1,51 @@
+import type * as ChildProcessModule from 'node:child_process'
+import { describe, expect, it, vi } from 'vitest'
+import type { ExactDaemonIncarnation } from './daemon-incarnation-evidence-types'
+
+const { execFileMock, execFileSyncMock } = vi.hoisted(() => ({
+  execFileMock: vi.fn(
+    (
+      _file: string,
+      _args: readonly string[],
+      _options: unknown,
+      callback: (error: Error | null, result: { stdout: string; stderr: string }) => void
+    ) => {
+      callback(null, { stdout: `${new Date(1_700_000_000_000).toString()}\n`, stderr: '' })
+    }
+  ),
+  execFileSyncMock: vi.fn(() => '')
+}))
+
+vi.mock('node:child_process', async (importOriginal) => ({
+  ...(await importOriginal<typeof ChildProcessModule>()),
+  execFile: execFileMock,
+  execFileSync: execFileSyncMock
+}))
+
+const { probeDaemonProcessIdentity } = await import('./daemon-incarnation-evidence')
+
+const endpoint = { socketPath: '/runtime/daemon.sock', tokenPath: '/runtime/daemon.token' }
+const exactIncarnation: ExactDaemonIncarnation = {
+  identity: { pid: 42, startedAtMs: 1_700_000_000_000, launchNonce: 'launch-a' }
+}
+
+describe('daemon audit evidence main-thread cost', () => {
+  it('reads the macOS process start time without a synchronous main-thread spawn', async () => {
+    await expect(
+      probeDaemonProcessIdentity(exactIncarnation, endpoint, {
+        platform: 'darwin',
+        signalProcess: () => 'occupied',
+        readCommandLine: async () =>
+          `node daemon-entry --socket ${endpoint.socketPath} --token ${endpoint.tokenPath}`
+      })
+    ).resolves.toMatchObject({ state: 'present', reason: 'macos_identity_match' })
+
+    expect(execFileSyncMock).not.toHaveBeenCalled()
+    expect(execFileMock).toHaveBeenCalledWith(
+      'ps',
+      ['-p', '42', '-o', 'lstart='],
+      expect.anything(),
+      expect.any(Function)
+    )
+  })
+})
diff --git a/src/main/daemon/daemon-incarnation-evidence-types.ts b/src/main/daemon/daemon-incarnation-evidence-types.ts
index 537a03fc191..48c61da177f 100644
--- a/src/main/daemon/daemon-incarnation-evidence-types.ts
+++ b/src/main/daemon/daemon-incarnation-evidence-types.ts
@@ -70,6 +70,6 @@ export type DaemonProcessProbeDependencies = {
   readLinuxStat?: (pid: number) => Promise<LinuxStatEvidence>
   readBootIdentity?: () => Promise<string | undefined>
   readCommandLine?: (pid: number, platform: NodeJS.Platform) => Promise<string | undefined>
-  readProcessStartedAtMs?: (pid: number) => number | null
+  readProcessStartedAtMs?: (pid: number) => Promise<number | null>
   queryWindowsProcess?: (pid: number) => Promise<WindowsProcessEvidence>
 }
diff --git a/src/main/daemon/daemon-incarnation-evidence.test.ts b/src/main/daemon/daemon-incarnation-evidence.test.ts
index 73e4a337e3c..f87bfafce94 100644
--- a/src/main/daemon/daemon-incarnation-evidence.test.ts
+++ b/src/main/daemon/daemon-incarnation-evidence.test.ts
@@ -61,7 +61,7 @@ describe('daemon process identity evidence', () => {
   })
 
   it('proves Linux pid reuse from native start ticks without derived milliseconds', async () => {
-    const readProcessStartedAtMs = vi.fn(() => exactIncarnation.identity.startedAtMs)
+    const readProcessStartedAtMs = vi.fn(async () => exactIncarnation.identity.startedAtMs)
 
     await expect(
       probeDaemonProcessIdentity(
@@ -247,7 +247,7 @@ describe('daemon process identity evidence', () => {
         signalProcess: () => 'occupied',
         readCommandLine: async () =>
           `node daemon-entry --socket ${endpoint.socketPath} --token ${endpoint.tokenPath}`,
-        readProcessStartedAtMs: () => exactIncarnation.identity.startedAtMs + 2_500
+        readProcessStartedAtMs: async () => exactIncarnation.identity.startedAtMs + 2_500
       })
     ).resolves.toMatchObject({ state: 'unknown', reason: 'macos_start_time_mismatch' })
   })
diff --git a/src/main/daemon/daemon-incarnation-evidence.ts b/src/main/daemon/daemon-incarnation-evidence.ts
index b5c5429a9f2..2a33ffc175f 100644
--- a/src/main/daemon/daemon-incarnation-evidence.ts
+++ b/src/main/daemon/daemon-incarnation-evidence.ts
@@ -16,6 +16,7 @@ import {
   inspectProcessSignal,
   queryWindowsProcess,
   readLinuxStat,
+  readMacosProcessStartedAtMs,
   readProcessCommandLine
 } from './daemon-process-inspection'
 
@@ -34,6 +35,11 @@ export {
 
 const POSIX_START_TIME_TOLERANCE_MS = 1_500
 
+// Why: linux start time comes from procfs via the shared helper; only darwin's `ps` spawn
+// had to move off the main thread.
+const readLinuxProcessStartedAtMs = async (pid: number): Promise<number | null> =>
+  getProcessStartedAtMs(pid)
+
 export async function probeDaemonProcessIdentity(
   exactIncarnation: ExactDaemonIncarnation | null,
   endpoint: { socketPath: string; tokenPath: string },
@@ -134,7 +140,7 @@ async function probeLinuxProcess(
     ])
   }
 
-  const startedAtMs = (dependencies.readProcessStartedAtMs ?? getProcessStartedAtMs)(
+  const startedAtMs = await (dependencies.readProcessStartedAtMs ?? readLinuxProcessStartedAtMs)(
     exactIncarnation.identity.pid
   )
   if (startedAtMs === null) {
@@ -172,7 +178,7 @@ async function probeMacosProcess(
   if (!commandLineMatchesDaemon(commandLine, endpoint.socketPath, endpoint.tokenPath)) {
     return unknown('command_line_mismatch', ['process_command_line'])
   }
-  const startedAtMs = (dependencies.readProcessStartedAtMs ?? getProcessStartedAtMs)(
+  const startedAtMs = await (dependencies.readProcessStartedAtMs ?? readMacosProcessStartedAtMs)(
     exactIncarnation.identity.pid
   )
   if (startedAtMs === null) {
diff --git a/src/main/daemon/daemon-process-inspection.test.ts b/src/main/daemon/daemon-process-inspection.test.ts
index 2b612fd068c..01f5f5b2e38 100644
--- a/src/main/daemon/daemon-process-inspection.test.ts
+++ b/src/main/daemon/daemon-process-inspection.test.ts
@@ -1,5 +1,9 @@
 import { describe, expect, it, vi } from 'vitest'
-import { queryWindowsProcess, readProcessCommandLine } from './daemon-process-inspection'
+import {
+  queryWindowsProcess,
+  readMacosProcessStartedAtMs,
+  readProcessCommandLine
+} from './daemon-process-inspection'
 
 describe('daemon process inspection', () => {
   it('falls back to ps when Linux procfs returns an empty command line', async () => {
@@ -23,6 +27,50 @@ describe('daemon process inspection', () => {
     expect(runCommand).not.toHaveBeenCalled()
   })
 
+  it('asks PowerShell to report a failed CIM query instead of an absent process', async () => {
+    const runCommand = vi.fn(
+      async (_file: string, _args: string[], _timeoutMs: number) =>
+        '{"status":"present","cmd":"daemon","start":1}'
+    )
+
+    await queryWindowsProcess(42, { runCommand })
+
+    const script = runCommand.mock.calls[0]?.[1].at(-1) ?? ''
+    expect(script).toContain("$ErrorActionPreference = 'Stop'")
+    expect(script).toMatch(/catch \{[^}]*query_failed/)
+  })
+
+  it('keeps a failed CIM query indeterminate instead of proving the process gone', async () => {
+    const runCommand = vi.fn(async () => '{"status":"query_failed"}')
+
+    await expect(queryWindowsProcess(42, { runCommand })).resolves.toEqual({
+      status: 'unavailable'
+    })
+  })
+
+  it('never reads a probe result without a success marker as proof of absence', async () => {
+    const runCommand = vi.fn(async () => '{"exists":false}')
+
+    await expect(queryWindowsProcess(42, { runCommand })).resolves.toEqual({
+      status: 'unavailable'
+    })
+  })
+
+  it('reports absence only from a CIM query that ran and found nothing', async () => {
+    const runCommand = vi.fn(async () => '{"status":"missing"}')
+
+    await expect(queryWindowsProcess(42, { runCommand })).resolves.toEqual({ status: 'missing' })
+  })
+
+  it('reads the macOS start time through an async spawn', async () => {
+    const runCommand = vi.fn(async () => 'Sat Jan  1 00:00:00 2028\n')
+
+    await expect(readMacosProcessStartedAtMs(42, { runCommand })).resolves.toBe(
+      Date.parse('Sat Jan  1 00:00:00 2028')
+    )
+    expect(runCommand).toHaveBeenCalledWith('ps', ['-p', '42', '-o', 'lstart='], 2_000)
+  })
+
   it.each([0, -1, 1.5, Number.MAX_SAFE_INTEGER + 1, Number.NaN])(
     'rejects unsafe Windows pid %s before command interpolation',
     async (pid) => {
diff --git a/src/main/daemon/daemon-process-inspection.ts b/src/main/daemon/daemon-process-inspection.ts
index 6dbc8ed55c4..282ba5ebbfb 100644
--- a/src/main/daemon/daemon-process-inspection.ts
+++ b/src/main/daemon/daemon-process-inspection.ts
@@ -63,6 +63,9 @@ export async function readProcessCommandLine(
   }
 }
 
+// Why: Get-CimInstance errors (Winmgmt down, corrupt WMI repository, access denied) are
+// non-terminating and exit 0 with an empty $p, which is indistinguishable from "no such
+// process" — so the script reports query failure explicitly instead of asserting absence.
 export async function queryWindowsProcess(
   pid: number,
   dependencies: DaemonProcessInspectionDependencies = {}
@@ -78,23 +81,26 @@ export async function queryWindowsProcess(
         '-NoProfile',
         '-NonInteractive',
         '-Command',
-        `$p = Get-CimInstance Win32_Process -Filter "ProcessId = ${pid}"; ` +
-          `if (!$p) { @{ exists = $false } | ConvertTo-Json -Compress } else { ` +
+        `$ErrorActionPreference = 'Stop'; ` +
+          `try { $p = Get-CimInstance Win32_Process -Filter "ProcessId = ${pid}" } ` +
+          `catch { @{ status = 'query_failed' } | ConvertTo-Json -Compress; exit 0 }; ` +
+          `if (!$p) { @{ status = 'missing' } | ConvertTo-Json -Compress; exit 0 }; ` +
           `$start = $null; if ($p.CreationDate) { ` +
           `$start = [long]([DateTimeOffset]$p.CreationDate).ToUnixTimeMilliseconds() }; ` +
-          `@{ exists = $true; cmd = $p.CommandLine; start = $start } | ConvertTo-Json -Compress }`
+          `@{ status = 'present'; cmd = $p.CommandLine; start = $start } | ConvertTo-Json -Compress`
       ],
       3_000
     )
     const parsed = JSON.parse(stdout.trim()) as {
-      exists?: unknown
+      status?: unknown
       cmd?: unknown
       start?: unknown
     }
-    if (parsed.exists === false) {
+    // Only a query that ran and found nothing proves absence; anything else stays indeterminate.
+    if (parsed.status === 'missing') {
       return { status: 'missing' }
     }
-    if (parsed.exists !== true) {
+    if (parsed.status !== 'present') {
       return { status: 'unavailable' }
     }
     return {
@@ -108,6 +114,22 @@ export async function queryWindowsProcess(
   }
 }
 
+// Why: `ps` is darwin's only start-time source and this audit-only probe runs in the
+// Electron main process, where the sync spawn blocks every IPC/UI turn for its duration.
+export async function readMacosProcessStartedAtMs(
+  pid: number,
+  dependencies: DaemonProcessInspectionDependencies = {}
+): Promise<number | null> {
+  const runCommand = dependencies.runCommand ?? runInspectionCommand
+  try {
+    const stdout = await runCommand('ps', ['-p', String(pid), '-o', 'lstart='], 2_000)
+    const startedAtMs = Date.parse(stdout.trim())
+    return Number.isFinite(startedAtMs) ? startedAtMs : null
+  } catch {
+    return null
+  }
+}
+
 async function runInspectionCommand(
   file: string,
   args: string[],
diff --git a/src/main/daemon/daemon-pty-adapter.ts b/src/main/daemon/daemon-pty-adapter.ts
index 9fcf5a8633d..ef60ca5d9f1 100644
--- a/src/main/daemon/daemon-pty-adapter.ts
+++ b/src/main/daemon/daemon-pty-adapter.ts
@@ -77,7 +77,7 @@ import {
   type DaemonAuditTrigger
 } from './daemon-audit-classifier'
 import type { DaemonEvidenceSource, ExactDaemonIncarnation } from './daemon-incarnation-evidence'
-import { trackDaemonAuditEligibility } from './daemon-audit-eligibility-event'
+import { createDaemonAuditEligibilityTracker } from './daemon-audit-eligibility-event'
 
 type PendingDaemonSpawnOperation = {
   exitsBySessionId: Map<string, { incarnationId?: string }[]>
@@ -159,6 +159,8 @@ export class DaemonPtyAdapter implements IPtyProvider {
   private lastAuthenticatedIdentity: DaemonEndpointIdentity | null = null
   private exactDaemonIncarnation: ExactDaemonIncarnation | null = null
   private lastAuditObservation: DaemonAuditObservation | null = null
+  // Why: every listProcesses call republishes the same observation; unthrottled it drains the shared per-session telemetry ceiling.
+  private readonly trackAuditEligibility = createDaemonAuditEligibilityTracker()
   private auditObservationListeners: ((observation: DaemonAuditObservation) => void)[] = []
   private identityChangeListeners: ((event: DaemonIdentityChangeEvent) => void)[] = []
   private historyManager: HistoryManager | null
@@ -1723,7 +1725,7 @@ export class DaemonPtyAdapter implements IPtyProvider {
 
   private publishAuditObservation(observation: DaemonAuditObservation): void {
     this.lastAuditObservation = observation
-    trackDaemonAuditEligibility(observation)
+    this.trackAuditEligibility(observation)
     notifyAuditListeners(this.auditObservationListeners, observation)
   }