diff --git a/Sources/ScreenStatetKit/Actions/ActionLocker.swift b/Sources/ScreenStatetKit/Actions/ActionLocker.swift
index 2385662..98135fb 100644
--- a/Sources/ScreenStatetKit/Actions/ActionLocker.swift
+++ b/Sources/ScreenStatetKit/Actions/ActionLocker.swift
@@ -5,56 +5,59 @@
 //  Created by Anthony on 4/12/25.
 //
 
-
 import Foundation
 
-
 public struct ActionLocker {
-    
+
     /// Use this when the locker is confined to a single actor or execution context.
-    /// No additional isolation is required as long as it is not accessed concurrently.
+    /// - Warning: Not thread-safe. For concurrent use, prefer ``ActionLocker/isolated``.
     public static var nonIsolated: NonIsolatedActionLocker { .init() }
-    
+
     /// Use this when the locker is shared across multiple actors or concurrent contexts.
     /// This variant provides the necessary isolation to ensure thread safety.
     public static var isolated: IsolatedActionLocker { .init() }
 }
 
-//MARK: - Isolated
+// MARK: - Isolated
 public actor IsolatedActionLocker {
-    
+
     let locker: NonIsolatedActionLocker
-    
+
     internal init() {
         locker = .init()
     }
-    
+
     public func lock(_ action: ActionLockable) throws {
         try locker.lock(action)
     }
-    
+
     public func unlock(_ action: ActionLockable) {
         locker.unlock(action)
     }
-    
+
     public func canExecute(_ action: ActionLockable) -> Bool {
         locker.canExecute(action)
     }
-    
+
     public func free() {
         locker.free()
     }
 }
 
-//MARK: - Nonisolated
+// MARK: - Nonisolated
+/// A non-thread-safe action locker for use within a single concurrency context.
+///
+/// - Important: This type has no synchronisation. It must only be accessed
+///   from a single actor or serial queue. For use across multiple concurrent
+///   contexts, use ``IsolatedActionLocker`` instead.
 public final class NonIsolatedActionLocker {
-    
+
     private var actions: [AnyHashable: Bool]
-    
+
     internal init() {
         actions = .init()
     }
-    
+
     public func lock(_ action: ActionLockable) throws {
         let isRunning = actions[action.lockKey] ?? false
         guard !isRunning else {
@@ -62,12 +65,12 @@ public final class NonIsolatedActionLocker {
         }
         actions.updateValue(true, forKey: action.lockKey)
     }
-    
+
     public func unlock(_ action: ActionLockable) {
         guard actions[action.lockKey] != .none else { return }
         actions.updateValue(false, forKey: action.lockKey)
     }
-    
+
     public func canExecute(_ action: ActionLockable) -> Bool {
         do {
             try lock(action)
@@ -76,16 +79,15 @@ public final class NonIsolatedActionLocker {
             return false
         }
     }
-    
+
     public func free() {
         actions.removeAll()
     }
 }
 
 extension ActionLocker {
-    
+
     public enum Errors: Error {
         case actionIsRunning
     }
 }
-
diff --git a/Sources/ScreenStatetKit/States/ScreenState.swift b/Sources/ScreenStatetKit/States/ScreenState.swift
index adb395f..3ba9cc2 100644
--- a/Sources/ScreenStatetKit/States/ScreenState.swift
+++ b/Sources/ScreenStatetKit/States/ScreenState.swift
@@ -2,11 +2,14 @@ import SwiftUI
 import Combine
 import Observation
 
-//MARK: - Base Screen States
+// MARK: - Base Screen States
 @MainActor
 @Observable
-open class ScreenState: Sendable {
-    
+// @unchecked Sendable: safe because all mutable state is @MainActor-isolated.
+// Subclasses must maintain this invariant — all stored properties must be
+// either immutable or @MainActor-isolated.
+open class ScreenState: @unchecked Sendable {
+
     public var isLoading: Bool = false {
         didSet {
             guard parentStateOption.contains(.loading) else { return }
@@ -17,7 +20,7 @@ open class ScreenState: Sendable {
             }
         }
     }
-    
+
     public var displayError: DisplayableError? {
         didSet {
             if let displayError {
@@ -30,16 +33,16 @@ open class ScreenState: Sendable {
             }
         }
     }
-    
+
     private weak var parentState: ScreenState?
     private let parentStateOption: BindingParentStateOption
-    
+
     private var loadingTaskCount: Int = 0 {
         didSet {
             updateStateLoading()
         }
     }
-    
+
     public init() {
         parentStateOption = .all
     }
@@ -48,28 +51,28 @@ open class ScreenState: Sendable {
         parentState = states
         self.parentStateOption = options
     }
-    
+
     public init(states: ScreenState) {
         parentState = states
         self.parentStateOption = .all
     }
 }
 
-//MARK: - Updaters
+// MARK: - Updaters
 extension ScreenState {
-    
+
     public struct BindingParentStateOption: OptionSet, Sendable {
-        
+
         public let rawValue: Int
         public static let loading = BindingParentStateOption(rawValue: 1 << 0)
         public static let error = BindingParentStateOption(rawValue: 1 << 1)
         public static let all: BindingParentStateOption = [.loading, .error]
-        
+
         public init(rawValue: Int) {
             self.rawValue = rawValue
         }
     }
-    
+
     private func updateStateLoading() {
         let loading = loadingTaskCount > 0
         if loading != self.isLoading {
@@ -78,27 +81,27 @@ extension ScreenState {
             }
         }
     }
-    
+
     public func showError(_ error: LocalizedError) {
         withAnimation {
             self.displayError = .init(message: error.localizedDescription)
         }
     }
-    
+
     public func loadingStarted() {
         loadingTaskCount += 1
     }
-    
+
     public func loadingFinished() {
         guard loadingTaskCount > 0 else { return }
         loadingTaskCount -= 1
     }
-    
+
     public func loadingStarted(action: LoadingTrackable) {
         guard action.canTrackLoading else { return }
         loadingStarted()
     }
-    
+
     public func loadingFinished(action: LoadingTrackable) {
         guard action.canTrackLoading else { return }
         loadingFinished()
diff --git a/Sources/ScreenStatetKit/States/StateUpdatable.swift b/Sources/ScreenStatetKit/States/StateUpdatable.swift
index c65a80d..cbb7821 100644
--- a/Sources/ScreenStatetKit/States/StateUpdatable.swift
+++ b/Sources/ScreenStatetKit/States/StateUpdatable.swift
@@ -9,15 +9,14 @@ import SwiftUI
 
 @MainActor
 public protocol StateUpdatable {
-    
+
     func updateState(withAnimation animation: Animation?,
                      _ updateBlock: @MainActor (_ state: Self) -> Void)
 }
 
-
 extension StateUpdatable {
-    
-    public func updateState(withAnimation animation: Animation? = .smooth,
+
+    public func updateState(withAnimation animation: Animation? = .none,
                             _ updateBlock: @MainActor (_ state: Self) -> Void) {
         var transaction = Transaction()
         transaction.animation = animation