diff --git a/src/main/codex/codex-hook-trust-grant.test.ts b/src/main/codex/codex-hook-trust-grant.test.ts
index 5292be120c1..fdd5e27fd40 100644
--- a/src/main/codex/codex-hook-trust-grant.test.ts
+++ b/src/main/codex/codex-hook-trust-grant.test.ts
@@ -70,13 +70,16 @@ function managedEntry(eventLabel: CodexTrustEntry['eventLabel']): CodexTrustEntr
   }
 }
 
-function buildPlan(entries: CodexTrustEntry[]): CodexManagedTrustGrantPlan {
+function buildPlan(
+  entries: CodexTrustEntry[],
+  host: CodexManagedTrustGrantPlan['host'] = { kind: 'native' }
+): CodexManagedTrustPlan {
   return {
     runtimeHomePath: runtimeHomeDir,
     tomlPath: join(runtimeHomeDir, 'config.toml'),
     managedCommand: MANAGED_COMMAND,
     managedEntries: entries,
-    host: { kind: 'native' },
+    host,
     telemetryLane: 'real-home'
   }
 }
@@ -270,6 +273,19 @@ describe('grantManagedCodexHookTrust', () => {
     expect(runner).toHaveBeenCalledTimes(2)
   })
 
+  it('bounds transient cooldowns when host identities churn', async () => {
+    _internals.setGrantSessionRunner(() => {
+      throw new Error('spawn ETIMEDOUT')
+    })
+    const entry = managedEntry('session_start')
+    for (let index = 0; index < 260; index += 1) {
+      await grantManagedCodexHookTrust(
+        buildPlan([entry], { kind: 'wsl', distro: `Distro-${index}`, linuxRuntimeHome: '/home/u' })
+      )
+    }
+    expect(_internals.transientCooldownCountForTests()).toBe(256)
+  })
+
   it('falls back on verify-failed without marking unsupported', async () => {
     const entries = [managedEntry('session_start')]
     const runner = vi.fn(async () => ({
diff --git a/src/main/codex/codex-hook-trust-grant.ts b/src/main/codex/codex-hook-trust-grant.ts
index f886dbb6344..d4b2f0fa359 100644
--- a/src/main/codex/codex-hook-trust-grant.ts
+++ b/src/main/codex/codex-hook-trust-grant.ts
@@ -40,6 +40,7 @@ import { isCodexStateDbBackfillPending } from './codex-state-db'
 // Why: a transiently hung app-server must not block launch prep on every pane.
 // The legacy lane remains available while a short, host-scoped cooldown runs.
 export const CODEX_TRUST_GRANT_TRANSIENT_RETRY_INTERVAL_MS = 5 * 60_000
+const MAX_TRANSIENT_TRUST_COOLDOWNS = 256
 
 /**
  * Ops escape hatch (not a setting): forces the unchanged fallback lane for the
@@ -109,7 +110,15 @@ function fallback(
 }
 
 function startTransientCooldown(hostKey: CodexAppServerHostKey): void {
+  transientRetryAfterByHost.delete(hostKey)
   transientRetryAfterByHost.set(hostKey, Date.now() + CODEX_TRUST_GRANT_TRANSIENT_RETRY_INTERVAL_MS)
+  while (transientRetryAfterByHost.size > MAX_TRANSIENT_TRUST_COOLDOWNS) {
+    const oldest = transientRetryAfterByHost.keys().next().value
+    if (oldest === undefined) {
+      break
+    }
+    transientRetryAfterByHost.delete(oldest)
+  }
 }
 
 type GrantAttempt = {
@@ -305,5 +314,8 @@ export const _internals = {
     diagnostics.verifyFailed = 0
     diagnostics.lastFallbackReason = null
     transientRetryAfterByHost.clear()
+  },
+  transientCooldownCountForTests(): number {
+    return transientRetryAfterByHost.size
   }
 }