diff --git a/Gaze/Models/PauseReason.swift b/Gaze/Models/PauseReason.swift
index 1dc60f8..72dca82 100644
--- a/Gaze/Models/PauseReason.swift
+++ b/Gaze/Models/PauseReason.swift
@@ -7,7 +7,7 @@
 
 import Foundation
 
-enum PauseReason: Codable, Sendable, Equatable, Hashable {
+enum PauseReason: nonisolated Codable, nonisolated Sendable, nonisolated Equatable, nonisolated Hashable {
     case manual
     case fullscreen
     case idle
@@ -38,3 +38,4 @@ enum PauseReason: Codable, Sendable, Equatable, Hashable {
         }
     }
 }
+
diff --git a/Gaze/Models/TimerIdentifier.swift b/Gaze/Models/TimerIdentifier.swift
index f74de62..b59fbe0 100644
--- a/Gaze/Models/TimerIdentifier.swift
+++ b/Gaze/Models/TimerIdentifier.swift
@@ -8,7 +8,7 @@
 import Foundation
 
 /// Unified identifier for both built-in and user-defined timers
-enum TimerIdentifier: Hashable, Codable {
+enum TimerIdentifier: Hashable, Codable, Sendable {
     case builtIn(TimerType)
     case user(id: String)
     
diff --git a/Gaze/Models/TimerState.swift b/Gaze/Models/TimerState.swift
index 7613ce9..edf36f1 100644
--- a/Gaze/Models/TimerState.swift
+++ b/Gaze/Models/TimerState.swift
@@ -7,7 +7,7 @@
 
 import Foundation
 
-struct TimerState: Equatable, Hashable {
+struct TimerState: Equatable, Hashable, Sendable {
     let identifier: TimerIdentifier
     var remainingSeconds: Int
     var isPaused: Bool
@@ -45,7 +45,7 @@ struct TimerState: Equatable, Hashable {
     }
 }
 
-enum TimerStateBuilder {
+enum TimerStateBuilder: Sendable {
     static func make(
         identifier: TimerIdentifier,
         intervalSeconds: Int,