diff --git a/config/oxlint-anti-slop.json b/config/oxlint-anti-slop.json
index 3e48b189302..d2ac1d35d75 100644
--- a/config/oxlint-anti-slop.json
+++ b/config/oxlint-anti-slop.json
@@ -38,7 +38,7 @@
     "anti-slop/no-shape-in-symbol-names": "off",
     "anti-slop/no-unknown-parameters": "off",
     "anti-slop/no-unknown-returns": "off",
-    "anti-slop/no-unknown-type-aliases": "off",
+    "anti-slop/no-unknown-type-aliases": "error",
     "anti-slop/no-unsafe-dictionary-type": "off",
     "anti-slop/no-widen-then-assert": "error",
     "anti-slop/require-readable-spacing": "off",
diff --git a/src/main/runtime/workspace-session-failed-write-rollback.ts b/src/main/runtime/workspace-session-failed-write-rollback.ts
index 4f9e79a03d7..7234446cb9d 100644
--- a/src/main/runtime/workspace-session-failed-write-rollback.ts
+++ b/src/main/runtime/workspace-session-failed-write-rollback.ts
@@ -2,9 +2,21 @@ import { isDeepStrictEqual } from 'node:util'
 import type { WorkspaceSessionState } from '../../shared/workspace-session-state-types'
 
 const MISSING = Symbol('missing')
-type RollbackValue = unknown
 
-function isRecord(value: RollbackValue): value is Record<string, unknown> {
+/** A JSON-shaped slot of persisted session state, or the absent-key sentinel. */
+type RollbackSlot =
+  | string
+  | number
+  | boolean
+  | null
+  | undefined
+  | typeof MISSING
+  | readonly RollbackSlot[]
+  | RollbackRecord
+
+type RollbackRecord = { readonly [key: string]: RollbackSlot }
+
+function isRecord(value: RollbackSlot): value is RollbackRecord {
   return (
     value !== MISSING &&
     typeof value === 'object' &&
@@ -15,10 +27,10 @@ function isRecord(value: RollbackValue): value is Record<string, unknown> {
 }
 
 function rollbackValue(
-  original: RollbackValue,
-  staged: RollbackValue,
-  current: RollbackValue
-): RollbackValue {
+  original: RollbackSlot,
+  staged: RollbackSlot,
+  current: RollbackSlot
+): RollbackSlot {
   if (isDeepStrictEqual(original, staged)) {
     return current
   }
@@ -29,7 +41,7 @@ function rollbackValue(
     return current
   }
   let changed = false
-  const next: Record<string, unknown> = { ...current }
+  const next: Record<string, RollbackSlot> = { ...current }
   for (const key of new Set([
     ...Object.keys(original),
     ...Object.keys(staged),
diff --git a/src/renderer/src/hooks/direct-ssh-host-hydration.ts b/src/renderer/src/hooks/direct-ssh-host-hydration.ts
index 419dc134075..2c326501760 100644
--- a/src/renderer/src/hooks/direct-ssh-host-hydration.ts
+++ b/src/renderer/src/hooks/direct-ssh-host-hydration.ts
@@ -18,7 +18,7 @@ import { directSshAuthoritiesEqual } from './direct-ssh-reconnect-tokens'
 
 export const DIRECT_SSH_HOST_READ_TIMEOUT_MS = 5_000
 
-type HostReadTimer = unknown
+type HostReadTimer = ReturnType<typeof setTimeout>
 
 export type DirectSshHostHydrationDeps = {
   store: Pick<StoreApi<AppState>, 'getState' | 'setState'>
@@ -121,7 +121,7 @@ export function createDirectSshHostHydration(
   const setTimer: NonNullable<DirectSshHostHydrationDeps['setTimer']> =
     deps.setTimer ?? ((callback, delayMs) => setTimeout(callback, delayMs))
   const clearTimer: NonNullable<DirectSshHostHydrationDeps['clearTimer']> =
-    deps.clearTimer ?? ((timer) => clearTimeout(timer as ReturnType<typeof setTimeout>))
+    deps.clearTimer ?? ((timer) => clearTimeout(timer))
   const catalogRevisionByTarget = new Map<string, number>()
   const catalogInFlight = new Map<string, Promise<'complete' | 'degraded' | 'stale'>>()
   const pendingDeadlines = new Set<{ timer: HostReadTimer; settle: () => void }>()
diff --git a/src/renderer/src/hooks/direct-ssh-reconnect-coordinator-stabilization.ts b/src/renderer/src/hooks/direct-ssh-reconnect-coordinator-stabilization.ts
index f20ea1e4a30..9924e55d70b 100644
--- a/src/renderer/src/hooks/direct-ssh-reconnect-coordinator-stabilization.ts
+++ b/src/renderer/src/hooks/direct-ssh-reconnect-coordinator-stabilization.ts
@@ -5,7 +5,7 @@ export type DirectSshReconnectTargetState = {
   authority: DirectSshAuthority
   installedAt: number
   dampUntil: number | null
-  timer: DirectSshReconnectTimer
+  timer: DirectSshReconnectTimer | null
 }
 
 export function createDirectSshReconnectTargetState(
diff --git a/src/renderer/src/hooks/direct-ssh-reconnect-coordinator-types.ts b/src/renderer/src/hooks/direct-ssh-reconnect-coordinator-types.ts
index 6cc76174ed1..31dfbe5a8ea 100644
--- a/src/renderer/src/hooks/direct-ssh-reconnect-coordinator-types.ts
+++ b/src/renderer/src/hooks/direct-ssh-reconnect-coordinator-types.ts
@@ -113,7 +113,7 @@ export type DirectSshCoordinatorTelemetry = {
   damped: boolean
 }
 
-export type DirectSshReconnectTimer = unknown
+export type DirectSshReconnectTimer = ReturnType<typeof setTimeout>
 
 export type DirectSshReconnectCoordinatorDeps = {
   scheduler: DirectSshWorktreeRefreshScheduler
diff --git a/src/renderer/src/hooks/direct-ssh-reconnect-coordinator.ts b/src/renderer/src/hooks/direct-ssh-reconnect-coordinator.ts
index 7ddf3892ff8..01474789f1c 100644
--- a/src/renderer/src/hooks/direct-ssh-reconnect-coordinator.ts
+++ b/src/renderer/src/hooks/direct-ssh-reconnect-coordinator.ts
@@ -42,9 +42,7 @@ export function createDirectSshReconnectCoordinator(
   const now = deps.now ?? Date.now
   const setTimer =
     deps.setTimer ?? ((callback: () => void, delayMs: number) => setTimeout(callback, delayMs))
-  const clearTimer =
-    deps.clearTimer ??
-    ((timer: DirectSshReconnectTimer) => clearTimeout(timer as ReturnType<typeof setTimeout>))
+  const clearTimer = deps.clearTimer ?? ((timer: DirectSshReconnectTimer) => clearTimeout(timer))
   const stabilizationMs = deps.stabilizationMs ?? DIRECT_SSH_RELAY_STABILIZATION_MS
   const targets = new Map<string, DirectSshReconnectTargetState>()
   let stopped = false