Signed-off-by: Matt Bruce <mbrucedogs@gmail.com>

Documentation/Design.md

@@ -9,7 +9,7 @@
 The central `actor` that coordinates all storage operations. It acts as the primary API surface and handles routing, catalog validation, and migration.
 
 ### StorageKey
-A protocol that defines the metadata for a single piece of persistent data.
+A generic struct that defines the metadata for a single piece of persistent data.
 - **Value**: The type of the data (Codable).
 - **Domain**: Where the data is stored (UserDefaults, Keychain, FileSystem, etc.).
 - **Security**: How the data is secured (None, Keychain-native, or custom Encryption).

Documentation/Migration.md

@@ -1,7 +1,7 @@
 # LocalData Migration Guide
 
 ## Overview
-`LocalData` provides protocol-based migration support to move data from legacy storage locations to modern `StorageKey` definitions.
+`LocalData` provides protocol-based migration support to move data from legacy storage locations to modern `StorageKey` values.
 
 ## Automatic Migration
 When calling `get(_:)` on a key, the `StorageRouter` automatically:
@@ -25,16 +25,30 @@ This iterates through all keys in the catalog and calls `forceMigration(for:)` o
 ### Simple Legacy Migration
 For 1:1 migrations, attach a `SimpleLegacyMigration`:
 ```swift
-struct MyNewKey: StorageKey {
-    // ...
-    var migration: AnyStorageMigration? {
-        AnyStorageMigration(
-            SimpleLegacyMigration(
-                destinationKey: self,
-                sourceKey: .key(LegacyKey(name: "old_key_name", domain: .userDefaults(suite: nil)))
+extension StorageKey where Value == String {
+    static let legacyToken = StorageKey(
+        name: "old_key_name",
+        domain: .userDefaults(suite: nil),
+        security: .none,
+        serializer: .json,
+        owner: "MigrationDemo",
+        description: "Legacy token stored in UserDefaults."
+    )
+
+    static let modernToken = StorageKey(
+        name: "modern_token",
+        domain: .keychain(service: "com.myapp"),
+        owner: "MigrationDemo",
+        description: "Modern token stored in Keychain.",
+        migration: { key in
+            AnyStorageMigration(
+                SimpleLegacyMigration(
+                    destinationKey: key,
+                    sourceKey: .key(StorageKey.legacyToken)
+                )
             )
-        )
-    }
+        }
+    )
 }
 ```
 
@@ -42,9 +56,9 @@ struct MyNewKey: StorageKey {
 For complex scenarios, attach an explicit migration:
 ```swift
 struct MyMigration: StorageMigration {
-    typealias DestinationKey = MyNewKey
+    typealias Value = String
 
-    let destinationKey = MyNewKey()
+    let destinationKey = StorageKey.modernToken
 
     func shouldMigrate(using router: StorageRouter, context: MigrationContext) async throws -> Bool {
         try await router.exists(destinationKey)
@@ -56,9 +70,13 @@ struct MyMigration: StorageMigration {
     }
 }
 
-extension MyNewKey {
-    var migration: AnyStorageMigration? {
-        AnyStorageMigration(MyMigration())
-    }
+extension StorageKey where Value == String {
+    static let modernToken = StorageKey(
+        name: "modern_token",
+        domain: .keychain(service: "com.myapp"),
+        owner: "MigrationDemo",
+        description: "Modern token stored in Keychain.",
+        migration: { _ in AnyStorageMigration(MyMigration()) }
+    )
 }
 ```

Documentation/Migration_Refactor_Plan_Clean.md

@@ -61,10 +61,10 @@ Follow AGENTS.md Clean Architecture and File Organization Principles for all new
 ```swift
 /// Core migration protocol with high-level methods
 public protocol StorageMigration: Sendable {
-    associatedtype DestinationKey: StorageKey
+    associatedtype Value: Codable & Sendable
     
     /// The destination storage key where migrated data will be stored
-    var destinationKey: DestinationKey { get }
+    var destinationKey: StorageKey<Value> { get }
     
     /// Validate if migration should proceed (conditional logic)
     func shouldMigrate(using router: StorageRouter, context: MigrationContext) async throws -> Bool
@@ -179,27 +179,47 @@ public struct MigrationContext: Sendable {
 }
 ```
 
-### 1.2 Update StorageKey Protocol
+### 1.2 Update StorageKey Type
 
-#### Modify `Sources/LocalData/Protocols/StorageKey.swift`
+#### Modify `Sources/LocalData/Models/StorageKey.swift`
 ```swift
-public protocol StorageKey: Sendable, CustomStringConvertible {
-    associatedtype Value: Codable & Sendable
+public struct StorageKey<Value: Codable & Sendable>: Sendable, CustomStringConvertible {
+    public let name: String
+    public let domain: StorageDomain
+    public let security: SecurityPolicy
+    public let serializer: Serializer<Value>
+    public let owner: String
+    public let description: String
+    public let availability: PlatformAvailability
+    public let syncPolicy: SyncPolicy
 
-    var name: String { get }
-    var domain: StorageDomain { get }
-    var security: SecurityPolicy { get }
-    var serializer: Serializer<Value> { get }
-    var owner: String { get }
-    var availability: PlatformAvailability { get }
-    var syncPolicy: SyncPolicy { get }
+    private let migrationBuilder: (@Sendable (StorageKey<Value>) -> AnyStorageMigration?)?
 
-    /// Optional migration for simple or complex scenarios
-    var migration: AnyStorageMigration? { get }
-}
+    public init(
+        name: String,
+        domain: StorageDomain,
+        security: SecurityPolicy = .recommended,
+        serializer: Serializer<Value> = .json,
+        owner: String,
+        description: String,
+        availability: PlatformAvailability = .all,
+        syncPolicy: SyncPolicy = .never,
+        migration: (@Sendable (StorageKey<Value>) -> AnyStorageMigration?)? = nil
+    ) {
+        self.name = name
+        self.domain = domain
+        self.security = security
+        self.serializer = serializer
+        self.owner = owner
+        self.description = description
+        self.availability = availability
+        self.syncPolicy = syncPolicy
+        self.migrationBuilder = migration
+    }
 
-extension StorageKey {
-    public var migration: AnyStorageMigration? { nil }
+    public var migration: AnyStorageMigration? {
+        migrationBuilder?(self)
+    }
 }
 ```
 
@@ -212,7 +232,7 @@ public struct AnyStorageKey: Sendable {
     public internal(set) var migration: AnyStorageMigration?
     private let migrateAction: @Sendable (StorageRouter) async throws -> Void
 
-    public init<Key: StorageKey>(_ key: Key) {
+    public init<Value>(_ key: StorageKey<Value>) {
         self.descriptor = .from(key)
         self.migration = key.migration
         self.migrateAction = { router in
@@ -231,13 +251,11 @@ public struct AnyStorageKey: Sendable {
 #### `Sources/LocalData/Migrations/SimpleLegacyMigration.swift`
 ```swift
 /// Simple 1:1 legacy migration
-public struct SimpleLegacyMigration<Destination: StorageKey>: StorageMigration {
-    public typealias DestinationKey = Destination
-    
-    public let destinationKey: Destination
+public struct SimpleLegacyMigration<Value: Codable & Sendable>: StorageMigration {
+    public let destinationKey: StorageKey<Value>
     public let sourceKey: AnyStorageKey
     
-    public init(destinationKey: Destination, sourceKey: AnyStorageKey) {
+    public init(destinationKey: StorageKey<Value>, sourceKey: AnyStorageKey) {
         self.destinationKey = destinationKey
         self.sourceKey = sourceKey
     }
@@ -290,13 +308,12 @@ public struct SimpleLegacyMigration<Destination: StorageKey>: StorageMigration {
 #### `Sources/LocalData/Migrations/AppVersionConditionalMigration.swift`
 ```swift
 /// Conditional migration for app version-based migration
-public struct AppVersionConditionalMigration<Destination: StorageKey>: ConditionalMigration {
-    public typealias DestinationKey = Destination
-    public let destinationKey: Destination
+public struct AppVersionConditionalMigration<Value: Codable & Sendable>: ConditionalMigration {
+    public let destinationKey: StorageKey<Value>
     public let minAppVersion: String
     public let fallbackMigration: AnyStorageMigration
     
-    public init(destinationKey: Destination, minAppVersion: String, fallbackMigration: AnyStorageMigration) {
+    public init(destinationKey: StorageKey<Value>, minAppVersion: String, fallbackMigration: AnyStorageMigration) {
         self.destinationKey = destinationKey
         self.minAppVersion = minAppVersion
         self.fallbackMigration = fallbackMigration
@@ -319,24 +336,21 @@ public struct AppVersionConditionalMigration<Destination: StorageKey>: Condition
 ```swift
 /// Migration protocol that supports data transformation during migration
 public protocol TransformingMigration: StorageMigration {
-    associatedtype SourceKey: StorageKey
+    associatedtype SourceValue: Codable & Sendable
     
-    var sourceKey: SourceKey { get }
-    func transform(_ source: SourceKey.Value) async throws -> DestinationKey.Value
+    var sourceKey: StorageKey<SourceValue> { get }
+    func transform(_ source: SourceValue) async throws -> Value
 }
 
-public struct DefaultTransformingMigration<Source: StorageKey, Destination: StorageKey>: TransformingMigration {
-    public typealias SourceKey = Source
-    public typealias DestinationKey = Destination
-    
-    public let destinationKey: Destination
-    public let sourceKey: Source
-    public let transform: (Source.Value) async throws -> Destination.Value
+public struct DefaultTransformingMigration<SourceValue: Codable & Sendable, DestinationValue: Codable & Sendable>: TransformingMigration {
+    public let destinationKey: StorageKey<DestinationValue>
+    public let sourceKey: StorageKey<SourceValue>
+    public let transform: (SourceValue) async throws -> DestinationValue
     
     public init(
-        destinationKey: Destination,
-        sourceKey: Source,
-        transform: @escaping (Source.Value) async throws -> Destination.Value
+        destinationKey: StorageKey<DestinationValue>,
+        sourceKey: StorageKey<SourceValue>,
+        transform: @escaping (SourceValue) async throws -> DestinationValue
     ) {
         self.destinationKey = destinationKey
         self.sourceKey = sourceKey
@@ -384,20 +398,18 @@ public struct DefaultTransformingMigration<Source: StorageKey, Destination: Stor
 /// Migration protocol that combines multiple sources into single destination
 public protocol AggregatingMigration: StorageMigration {
     var sourceKeys: [AnyStorageKey] { get }
-    func aggregate(_ sources: [AnyCodable]) async throws -> DestinationKey.Value
+    func aggregate(_ sources: [AnyCodable]) async throws -> Value
 }
 
-public struct DefaultAggregatingMigration<Destination: StorageKey>: AggregatingMigration {
-    public typealias DestinationKey = Destination
-    
-    public let destinationKey: Destination
+public struct DefaultAggregatingMigration<Value: Codable & Sendable>: AggregatingMigration {
+    public let destinationKey: StorageKey<Value>
     public let sourceKeys: [AnyStorageKey]
-    public let aggregate: ([AnyCodable]) async throws -> Destination.Value
+    public let aggregate: ([AnyCodable]) async throws -> Value
     
     public init(
-        destinationKey: Destination,
+        destinationKey: StorageKey<Value>,
         sourceKeys: [AnyStorageKey],
-        aggregate: @escaping ([AnyCodable]) async throws -> Destination.Value
+        aggregate: @escaping ([AnyCodable]) async throws -> Value
     ) {
         self.destinationKey = destinationKey
         self.sourceKeys = sourceKeys
@@ -524,7 +536,7 @@ internal func recordMigration(for descriptor: StorageKeyDescriptor) {
 
 **Enhanced `get` method:**
 ```swift
-public func get<Key: StorageKey>(_ key: Key) async throws -> Key.Value {
+public func get<Value>(_ key: StorageKey<Value>) async throws -> Value {
     try validateCatalogRegistration(for: key)
     try validatePlatformAvailability(for: key)
     
@@ -570,12 +582,12 @@ private func migrateAllRegisteredKeys() async throws {
 **New Methods:**
 ```swift
 /// Get migration history for a key
-public func migrationHistory<Key: StorageKey>(for key: Key) async -> Date? {
+public func migrationHistory<Value>(for key: StorageKey<Value>) async -> Date? {
     migrationHistory[key.name]
 }
 
 /// Force migration for a specific key using its attached migration
-public func forceMigration<Key: StorageKey>(for key: Key) async throws -> MigrationResult {
+public func forceMigration<Value>(for key: StorageKey<Value>) async throws -> MigrationResult {
     guard let migration = key.migration else {
         throw MigrationError.sourceDataNotFound
     }
@@ -871,39 +883,32 @@ struct UnifiedSettings: Codable {
 
 **`ConditionalMigrationKeys.swift`**
 ```swift
-extension StorageKeys {
-    struct LegacyConditionalProfileKey: StorageKey {
-        typealias Value = UserProfile
-        
-        let name = "legacy_conditional_profile"
-        let domain: StorageDomain = .userDefaults(suite: nil)
-        let security: SecurityPolicy = .none
-        let serializer: Serializer<UserProfile> = .json
-        let owner = "MigrationDemo"
-        let description = "Legacy profile for conditional migration demo."
-        let availability: PlatformAvailability = .all
-        let syncPolicy: SyncPolicy = .never
-    }
-    
-    struct ModernConditionalProfileKey: StorageKey {
-        typealias Value = UserProfile
-        
-        let name = "modern_conditional_profile"
-        let domain: StorageDomain = .keychain(service: "com.mbrucedogs.securestorage")
-        let security: SecurityPolicy = .keychain(
+extension StorageKey where Value == UserProfile {
+    static let legacyConditionalProfile = StorageKey(
+        name: "legacy_conditional_profile",
+        domain: .userDefaults(suite: nil),
+        security: .none,
+        serializer: .json,
+        owner: "MigrationDemo",
+        description: "Legacy profile for conditional migration demo.",
+        availability: .all,
+        syncPolicy: .never
+    )
+
+    static let modernConditionalProfile = StorageKey(
+        name: "modern_conditional_profile",
+        domain: .keychain(service: "com.mbrucedogs.securestorage"),
+        security: .keychain(
             accessibility: .afterFirstUnlock,
             accessControl: .userPresence
-        )
-        let serializer: Serializer<UserProfile> = .json
-        let owner = "MigrationDemo"
-        let description = "Modern profile for conditional migration demo."
-        let availability: PlatformAvailability = .all
-        let syncPolicy: SyncPolicy = .never
-        
-        var migration: AnyStorageMigration? {
-            AnyStorageMigration(ConditionalProfileMigration())
-        }
-    }
+        ),
+        serializer: .json,
+        owner: "MigrationDemo",
+        description: "Modern profile for conditional migration demo.",
+        availability: .all,
+        syncPolicy: .never,
+        migration: { _ in AnyStorageMigration(ConditionalProfileMigration()) }
+    )
 }
 ```
 
@@ -949,9 +954,9 @@ The `StorageMigration` protocol provides the foundation for all migration types:
 
 ```swift
 public protocol StorageMigration: Sendable {
-    associatedtype DestinationKey: StorageKey
+    associatedtype Value: Codable & Sendable
     
-    var destinationKey: DestinationKey { get }
+    var destinationKey: StorageKey<Value> { get }
     func shouldMigrate(using router: StorageRouter, context: MigrationContext) async throws -> Bool
     func migrate(using router: StorageRouter, context: MigrationContext) async throws -> MigrationResult
 }
@@ -1197,27 +1202,25 @@ conditional behavior.
 
 ### 1. Define Keys
 
-Extend `StorageKeys` with your own key types:
+Extend `StorageKey` with typed static keys:
 
 ```swift
 import LocalData
 
-extension StorageKeys {
-    struct UserTokenKey: StorageKey {
-        typealias Value = String
-        
-        let name = "user_token"
-        let domain: StorageDomain = .keychain(service: "com.myapp")
-        let security: SecurityPolicy = .keychain(
+extension StorageKey where Value == String {
+    static let userToken = StorageKey(
+        name: "user_token",
+        domain: .keychain(service: "com.myapp"),
+        security: .keychain(
             accessibility: .afterFirstUnlock,
             accessControl: .biometryAny
-        )
-        let serializer: Serializer<String> = .json
-        let owner = "AuthService"
-        let description = "Stores the current user auth token."
-        let availability: PlatformAvailability = .phoneOnly
-        let syncPolicy: SyncPolicy = .never
-    }
+        ),
+        serializer: .json,
+        owner: "AuthService",
+        description: "Stores the current user auth token.",
+        availability: .phoneOnly,
+        syncPolicy: .never
+    )
 }
 ```
 
@@ -1265,7 +1268,7 @@ extension UserTokenKey {
 
 ```swift
 // Save
-let key = StorageKeys.UserTokenKey()
+let key = StorageKey.userToken
 try await StorageRouter.shared.set("token123", for: key)
 
 // Retrieve (triggers automatic migration if needed)
@@ -1279,7 +1282,7 @@ try await StorageRouter.shared.remove(key)
 
 ```swift
 // Force migration
-let result = try await StorageRouter.shared.forceMigration(for: UserTokenKey())
+let result = try await StorageRouter.shared.forceMigration(for: StorageKey.userToken)
 ```
 ```
 
@@ -1380,10 +1383,8 @@ struct MigrationIntegrationTests {
 #### `Tests/LocalDataTests/Mocks/MockMigration.swift`
 ```swift
 /// Mock migration for testing
-struct MockMigration<Destination: StorageKey>: StorageMigration {
-    typealias DestinationKey = Destination
-    
-    let destinationKey: Destination
+struct MockMigration<Value: Codable & Sendable>: StorageMigration {
+    let destinationKey: StorageKey<Value>
     let shouldSucceed: Bool
     let shouldMigrateResult: Bool
     let migrationDelay: TimeInterval
@@ -1408,10 +1409,8 @@ struct MockMigration<Destination: StorageKey>: StorageMigration {
 }
 
 /// Failing migration for error testing
-struct FailingMigration<Destination: StorageKey>: StorageMigration {
-    typealias DestinationKey = Destination
-    
-    let destinationKey: Destination
+struct FailingMigration<Value: Codable & Sendable>: StorageMigration {
+    let destinationKey: StorageKey<Value>
     let error: MigrationError
     
     func shouldMigrate(using router: StorageRouter, context: MigrationContext) async throws -> Bool { true }
@@ -1547,7 +1546,7 @@ public enum MigrationUtils {
 ## Migration Checklist
 
 - [x] Create core protocol files
-- [x] Update StorageKey protocol with migration
+- [x] Update StorageKey type with migration
 - [x] Create concrete migration implementations
 - [x] Update StorageRouter integration with simple and advanced migration handling
 - [x] Add WatchOS/sync defaults to StorageMigration

Proposal.md

@@ -17,8 +17,8 @@ Create a single, typed, discoverable namespace for persisted app data with consi
 ## Architecture
 
 ### Core Components
-- **StorageKey** protocol - Defines storage configuration for each data type
-- **StorageKey.migration** - Optional protocol-based migration attached to a key
+- **StorageKey** (generic struct) - Defines storage configuration for each data type
+- **StorageKey.migration** - Optional migration attached to a key
 - **StorageRouter** actor - Main entry point coordinating all storage operations
 - **StorageProviding** protocol - Abstraction for storage operations
 - **StorageKeyCatalog** protocol - Catalog of keys for auditing/validation
@@ -54,7 +54,7 @@ Each helper is a dedicated actor providing thread-safe access to a specific stor
 - **DeviceInfo / SystemInfo** - Device and system metrics used by migrations
 
 ## Usage Pattern
-Apps extend StorageKeys with their own key types and use StorageRouter.shared. This follows the Notification.Name pattern for discoverable keys.
+Apps extend `StorageKey` with typed static keys (e.g., `extension StorageKey where Value == String`) and use `StorageRouter.shared`. This follows the Notification.Name pattern for discoverable keys while preserving value-type inference.
 
 ## Audit & Validation
 Apps can register multiple `StorageKeyCatalog`s (e.g., one per module) to generate audit reports and enforce key registration. Registration is additive and validates:

README.md

@@ -72,7 +72,6 @@ flowchart TD
 ## What Ships in the Package
 
 ### Protocols
-- **StorageKey** - Define storage configuration for each data type
 - **StorageProviding** - Abstraction for storage operations
 - **KeyMaterialProviding** - Supplies external key material for encryption
 - **StorageMigration** - Protocol-based migration workflows
@@ -110,6 +109,7 @@ These are used at app lifecycle start to tune library engine behaviors:
 - **KeychainAccessControl** - All 6 access control options (biometry, passcode, etc.)
 - **FileDirectory** - documents, caches, custom URL
 - **StorageError** - Comprehensive error types
+- **StorageKey** - Typed storage configuration (generic over Value)
 - **StorageKeyDescriptor** - Audit snapshot of a key’s storage metadata
 - **AnyStorageKey** - Type-erased storage key for catalogs
 - **AnyCodable** - Type-erased Codable for mixed-type payloads
@@ -126,27 +126,25 @@ These are used at app lifecycle start to tune library engine behaviors:
 ## Usage
 
 ### 1. Define Keys
-Extend `StorageKeys` with your own key types:
+Extend `StorageKey` with typed static keys:
 
 ```swift
 import LocalData
 
-extension StorageKeys {
-    struct UserTokenKey: StorageKey {
-        typealias Value = String
-        
-        let name = "user_token"
-        let domain: StorageDomain = .keychain(service: "com.myapp")
-        let security: SecurityPolicy = .keychain(
+extension StorageKey where Value == String {
+    static let userToken = StorageKey(
+        name: "user_token",
+        domain: .keychain(service: "com.myapp"),
+        security: .keychain(
             accessibility: .afterFirstUnlock,
             accessControl: .biometryAny
-        )
-        let serializer: Serializer<String> = .json
-        let owner = "AuthService"
-        let description = "Stores the current user auth token."
-        let availability: PlatformAvailability = .phoneOnly
-        let syncPolicy: SyncPolicy = .never
-    }
+        ),
+        serializer: .json,
+        owner: "AuthService",
+        description: "Stores the current user auth token.",
+        availability: .phoneOnly,
+        syncPolicy: .never
+    )
 }
 ```
 If you omit `security`, it defaults to `SecurityPolicy.recommended`.
@@ -154,7 +152,7 @@ If you omit `security`, it defaults to `SecurityPolicy.recommended`.
 ### 2. Use StorageRouter
 ```swift
 // Save
-let key = StorageKeys.UserTokenKey()
+let key = StorageKey.userToken
 try await StorageRouter.shared.set("token123", for: key)
 
 // Retrieve
@@ -174,13 +172,13 @@ struct UserProfile: Codable {
     let settings: [String: String]
 }
 
-extension StorageKeys {
-    struct ProfileKey: StorageKey {
-        typealias Value = UserProfile // Library handles serialization
-        let name = "user_profile"
-        let domain: StorageDomain = .fileSystem(directory: .documents)
-        // ... other properties
-    }
+extension StorageKey where Value == UserProfile {
+    static let profile = StorageKey(
+        name: "user_profile",
+        domain: .fileSystem(directory: .documents),
+        owner: "ProfileService",
+        description: "Stores the current user profile."
+    )
 }
 
         // ... other properties
@@ -199,19 +197,30 @@ When you define a `migration` on a key, `StorageRouter.get(key)` will automatica
 - It is returned to the caller.
 
 ```swift
-extension StorageKeys {
-    struct ModernKey: StorageKey {
-        typealias Value = String
-        // ... other properties
-        var migration: AnyStorageMigration? {
+extension StorageKey where Value == String {
+    static let legacyToken = StorageKey(
+        name: "legacy_token",
+        domain: .userDefaults(suite: nil),
+        security: .none,
+        serializer: .json,
+        owner: "AuthService",
+        description: "Legacy token stored in UserDefaults."
+    )
+
+    static let modernToken = StorageKey(
+        name: "modern_token",
+        domain: .keychain(service: "com.myapp"),
+        owner: "AuthService",
+        description: "Stores the current user auth token.",
+        migration: { key in
             AnyStorageMigration(
                 SimpleLegacyMigration(
-                    destinationKey: self,
-                    sourceKey: .key(LegacyKey())
+                    destinationKey: key,
+                    sourceKey: .key(StorageKey.legacyToken)
                 )
             )
         }
-    }
+    )
 }
 ```
 
@@ -220,10 +229,10 @@ For complex migrations, implement `StorageMigration` and attach it to the key.
 
 ```swift
 struct TokenMigration: StorageMigration {
-    typealias DestinationKey = StorageKeys.UserTokenKey
+    typealias Value = String
 
-    let destinationKey = StorageKeys.UserTokenKey()
-    let legacyKey = StorageKeys.LegacyTokenKey()
+    let destinationKey = StorageKey.userToken
+    let legacyKey = StorageKey.legacyToken
 
     func shouldMigrate(using router: StorageRouter, context: MigrationContext) async throws -> Bool {
         try await router.exists(legacyKey)
@@ -237,10 +246,14 @@ struct TokenMigration: StorageMigration {
     }
 }
 
-extension StorageKeys.UserTokenKey {
-    var migration: AnyStorageMigration? {
-        AnyStorageMigration(TokenMigration())
-    }
+extension StorageKey where Value == String {
+    static let userToken = StorageKey(
+        name: "user_token",
+        domain: .keychain(service: "com.myapp"),
+        owner: "AuthService",
+        description: "Stores the current user auth token.",
+        migration: { _ in AnyStorageMigration(TokenMigration()) }
+    )
 }
 ```
 
@@ -249,7 +262,7 @@ To ensure no "ghost data" remains in legacy keys (e.g., if a bug causes old code
 
 #### Manual Call
 ```swift
-try await StorageRouter.shared.forceMigration(for: StorageKeys.ModernKey())
+try await StorageRouter.shared.forceMigration(for: StorageKey.modernToken)
 ```
 
 #### Automated Startup Sweep
@@ -268,7 +281,7 @@ try await StorageRouter.shared.registerCatalog(ProfileCatalog())
 
 ## Storage Design Philosophy
 
-This app intentionally uses a **Type-Safe Storage Design**. Unlike standard iOS development which uses string keys (e.g., `UserDefaults.standard.string(forKey: "user_name")`), this library requires you to define a `StorageKey` type.
+This app intentionally uses a **Type-Safe Storage Design**. Unlike standard iOS development which uses string keys (e.g., `UserDefaults.standard.string(forKey: "user_name")`), this library requires you to define `StorageKey` values.
 
 ### Why types instead of strings?
 1.  **Safety**: The compiler prevents typos. You can't accidentally load from `"user_name"` and save to `"username"`.
@@ -453,15 +466,15 @@ LocalData can generate a catalog of all configured storage keys, even if no data
 
 ### Why `AnyStorageKey`?
 
-`StorageKey` has an associated type (`Value`), which means you cannot store different keys in a single array using `[StorageKey]` or `some StorageKey`. Swift requires type erasure for heterogeneous protocol values, so the catalog uses `[AnyStorageKey]` and builds descriptors behind the scenes.
+`StorageKey` is generic over `Value`, which means you cannot store different key value types in a single array using `[StorageKey]`. Swift requires type erasure for heterogeneous key values, so the catalog uses `[AnyStorageKey]` and builds descriptors behind the scenes.
 
 1) Define a catalog in your app that lists all keys:
 
 ```swift
 struct AppStorageCatalog: StorageKeyCatalog {
     let allKeys: [AnyStorageKey] = [
-        .key(StorageKeys.AppVersionKey()),
-        .key(StorageKeys.UserPreferencesKey())
+        .key(StorageKey.appVersion),
+        .key(StorageKey.userPreferences)
     ]
 }
 ```

Sources/LocalData/LocalData.swift

@@ -1,5 +0,0 @@
-// The Swift Programming Language
-// https://docs.swift.org/swift-book
-public enum StorageKeys {
-    
-}

Sources/LocalData/Migrations/AppVersionConditionalMigration.swift

@@ -1,15 +1,13 @@
 import Foundation
 
 /// Conditional migration for app version-based migration.
-public struct AppVersionConditionalMigration<Destination: StorageKey>: ConditionalMigration {
-    public typealias DestinationKey = Destination
-
-    public let destinationKey: Destination
+public struct AppVersionConditionalMigration<Value: Codable & Sendable>: ConditionalMigration {
+    public let destinationKey: StorageKey<Value>
     public let minAppVersion: String
     public let fallbackMigration: AnyStorageMigration
 
     public init(
-        destinationKey: Destination,
+        destinationKey: StorageKey<Value>,
         minAppVersion: String,
         fallbackMigration: AnyStorageMigration
     ) {

Sources/LocalData/Migrations/DefaultAggregatingMigration.swift

@@ -1,23 +1,21 @@
 import Foundation
 
-public struct DefaultAggregatingMigration<Destination: StorageKey>: AggregatingMigration {
-    public typealias DestinationKey = Destination
-
-    public let destinationKey: Destination
+public struct DefaultAggregatingMigration<Value: Codable & Sendable>: AggregatingMigration {
+    public let destinationKey: StorageKey<Value>
     public let sourceKeys: [AnyStorageKey]
-    public let aggregateAction: ([AnyCodable]) async throws -> Destination.Value
+    public let aggregateAction: ([AnyCodable]) async throws -> Value
 
     public init(
-        destinationKey: Destination,
+        destinationKey: StorageKey<Value>,
         sourceKeys: [AnyStorageKey],
-        aggregate: @escaping ([AnyCodable]) async throws -> Destination.Value
+        aggregate: @escaping ([AnyCodable]) async throws -> Value
     ) {
         self.destinationKey = destinationKey
         self.sourceKeys = sourceKeys
         self.aggregateAction = aggregate
     }
 
-    public func aggregate(_ sources: [AnyCodable]) async throws -> Destination.Value {
+    public func aggregate(_ sources: [AnyCodable]) async throws -> Value {
         try await aggregateAction(sources)
     }
 

Sources/LocalData/Migrations/DefaultTransformingMigration.swift

@@ -1,24 +1,21 @@
 import Foundation
 
-public struct DefaultTransformingMigration<Source: StorageKey, Destination: StorageKey>: TransformingMigration {
-    public typealias SourceKey = Source
-    public typealias DestinationKey = Destination
-
-    public let destinationKey: Destination
-    public let sourceKey: Source
-    public let transformAction: (Source.Value) async throws -> Destination.Value
+public struct DefaultTransformingMigration<SourceValue: Codable & Sendable, DestinationValue: Codable & Sendable>: TransformingMigration {
+    public let destinationKey: StorageKey<DestinationValue>
+    public let sourceKey: StorageKey<SourceValue>
+    public let transformAction: (SourceValue) async throws -> DestinationValue
 
     public init(
-        destinationKey: Destination,
-        sourceKey: Source,
-        transform: @escaping (Source.Value) async throws -> Destination.Value
+        destinationKey: StorageKey<DestinationValue>,
+        sourceKey: StorageKey<SourceValue>,
+        transform: @escaping (SourceValue) async throws -> DestinationValue
     ) {
         self.destinationKey = destinationKey
         self.sourceKey = sourceKey
         self.transformAction = transform
     }
 
-    public func transform(_ source: Source.Value) async throws -> Destination.Value {
+    public func transform(_ source: SourceValue) async throws -> DestinationValue {
         try await transformAction(source)
     }
 

Sources/LocalData/Migrations/SimpleLegacyMigration.swift

@@ -1,13 +1,11 @@
 import Foundation
 
 /// Simple 1:1 legacy migration.
-public struct SimpleLegacyMigration<Destination: StorageKey>: StorageMigration {
-    public typealias DestinationKey = Destination
-
-    public let destinationKey: Destination
+public struct SimpleLegacyMigration<Value: Codable & Sendable>: StorageMigration {
+    public let destinationKey: StorageKey<Value>
     public let sourceKey: AnyStorageKey
 
-    public init(destinationKey: Destination, sourceKey: AnyStorageKey) {
+    public init(destinationKey: StorageKey<Value>, sourceKey: AnyStorageKey) {
         self.destinationKey = destinationKey
         self.sourceKey = sourceKey
     }

Sources/LocalData/Models/AnyStorageKey.swift

@@ -3,7 +3,7 @@ public struct AnyStorageKey: Sendable {
     public internal(set) var migration: AnyStorageMigration?
     private let migrateAction: @Sendable (StorageRouter) async throws -> Void
 
-    public init<Key: StorageKey>(_ key: Key) {
+    public init<Value>(_ key: StorageKey<Value>) {
         self.descriptor = .from(key)
         self.migration = key.migration
         self.migrateAction = { router in
@@ -21,7 +21,7 @@ public struct AnyStorageKey: Sendable {
         self.migrateAction = migrateAction
     }
 
-    public static func key<Key: StorageKey>(_ key: Key) -> AnyStorageKey {
+    public static func key<Value>(_ key: StorageKey<Value>) -> AnyStorageKey {
         AnyStorageKey(key)
     }
 

Sources/LocalData/Models/StorageKey.swift

@@ -0,0 +1,40 @@
+import Foundation
+
+public struct StorageKey<Value: Codable & Sendable>: Sendable, CustomStringConvertible {
+    public let name: String
+    public let domain: StorageDomain
+    public let security: SecurityPolicy
+    public let serializer: Serializer<Value>
+    public let owner: String
+    public let description: String
+    public let availability: PlatformAvailability
+    public let syncPolicy: SyncPolicy
+
+    private let migrationBuilder: (@Sendable (StorageKey<Value>) -> AnyStorageMigration?)?
+
+    public init(
+        name: String,
+        domain: StorageDomain,
+        security: SecurityPolicy = .recommended,
+        serializer: Serializer<Value> = .json,
+        owner: String,
+        description: String,
+        availability: PlatformAvailability = .all,
+        syncPolicy: SyncPolicy = .never,
+        migration: (@Sendable (StorageKey<Value>) -> AnyStorageMigration?)? = nil
+    ) {
+        self.name = name
+        self.domain = domain
+        self.security = security
+        self.serializer = serializer
+        self.owner = owner
+        self.description = description
+        self.availability = availability
+        self.syncPolicy = syncPolicy
+        self.migrationBuilder = migration
+    }
+
+    public var migration: AnyStorageMigration? {
+        migrationBuilder?(self)
+    }
+}

Sources/LocalData/Models/StorageKeyDescriptor.swift

@@ -36,8 +36,8 @@ public struct StorageKeyDescriptor: Sendable, CustomStringConvertible {
         self.catalog = catalog
     }
 
-    public static func from<Key: StorageKey>(
-        _ key: Key,
+    public static func from<Value>(
+        _ key: StorageKey<Value>,
         catalog: String? = nil
     ) -> StorageKeyDescriptor {
         StorageKeyDescriptor(
@@ -45,7 +45,7 @@ public struct StorageKeyDescriptor: Sendable, CustomStringConvertible {
             domain: key.domain,
             security: key.security,
             serializer: key.serializer.name,
-            valueType: String(describing: Key.Value.self),
+            valueType: String(describing: Value.self),
             owner: key.owner,
             availability: key.availability,
             syncPolicy: key.syncPolicy,

Sources/LocalData/Protocols/AggregatingMigration.swift

@@ -3,5 +3,5 @@ import Foundation
 /// Migration protocol that combines multiple sources into a single destination.
 public protocol AggregatingMigration: StorageMigration {
     var sourceKeys: [AnyStorageKey] { get }
-    func aggregate(_ sources: [AnyCodable]) async throws -> DestinationKey.Value
+    func aggregate(_ sources: [AnyCodable]) async throws -> Value
 }

Sources/LocalData/Protocols/StorageKey+Defaults.swift

@@ -1,3 +0,0 @@
-public extension StorageKey {
-    var security: SecurityPolicy { .recommended }
-}

Sources/LocalData/Protocols/StorageKey.swift

@@ -1,20 +0,0 @@
-import Foundation
-
-public protocol StorageKey: Sendable, CustomStringConvertible {
-    associatedtype Value: Codable & Sendable
-
-    var name: String { get }
-    var domain: StorageDomain { get }
-    var security: SecurityPolicy { get }
-    var serializer: Serializer<Value> { get }
-    var owner: String { get }
-
-    var availability: PlatformAvailability { get }
-    var syncPolicy: SyncPolicy { get }
-
-    var migration: AnyStorageMigration? { get }
-}
-
-extension StorageKey {
-    public var migration: AnyStorageMigration? { nil }
-}

Sources/LocalData/Protocols/StorageMigration.swift

@@ -2,10 +2,10 @@ import Foundation
 
 /// Core migration protocol with high-level methods.
 public protocol StorageMigration: Sendable {
-    associatedtype DestinationKey: StorageKey
+    associatedtype Value: Codable & Sendable
 
     /// The destination storage key where migrated data will be stored.
-    var destinationKey: DestinationKey { get }
+    var destinationKey: StorageKey<Value> { get }
 
     /// Validate if migration should proceed (conditional logic).
     func shouldMigrate(using router: StorageRouter, context: MigrationContext) async throws -> Bool

Sources/LocalData/Protocols/StorageProviding.swift

@@ -1,7 +1,7 @@
 import Foundation
 
 public protocol StorageProviding: Sendable {
-    func set<Key: StorageKey>(_ value: Key.Value, for key: Key) async throws
-    func get<Key: StorageKey>(_ key: Key) async throws -> Key.Value
-    func remove<Key: StorageKey>(_ key: Key) async throws
+    func set<Value>(_ value: Value, for key: StorageKey<Value>) async throws
+    func get<Value>(_ key: StorageKey<Value>) async throws -> Value
+    func remove<Value>(_ key: StorageKey<Value>) async throws
 }

Sources/LocalData/Protocols/TransformingMigration.swift

@@ -2,8 +2,8 @@ import Foundation
 
 /// Migration protocol that supports data transformation during migration.
 public protocol TransformingMigration: StorageMigration {
-    associatedtype SourceKey: StorageKey
+    associatedtype SourceValue: Codable & Sendable
 
-    var sourceKey: SourceKey { get }
-    func transform(_ source: SourceKey.Value) async throws -> DestinationKey.Value
+    var sourceKey: StorageKey<SourceValue> { get }
+    func transform(_ source: SourceValue) async throws -> Value
 }

Sources/LocalData/Services/StorageRouter.swift

@@ -127,7 +127,7 @@ public actor StorageRouter: StorageProviding {
     }
 
     /// Returns the last migration date for a specific key, if available.
-    public func migrationHistory<Key: StorageKey>(for key: Key) -> Date? {
+    public func migrationHistory<Value>(for key: StorageKey<Value>) -> Date? {
         migrationHistory[key.name]
     }
     
@@ -138,7 +138,7 @@ public actor StorageRouter: StorageProviding {
     ///   - value: The value to store.
     ///   - key: The storage key defining where and how to store.
     /// - Throws: Various errors depending on the storage domain and security policy.
-    public func set<Key: StorageKey>(_ value: Key.Value, for key: Key) async throws {
+    public func set<Value>(_ value: Value, for key: StorageKey<Value>) async throws {
         Logger.debug(">>> [STORAGE] SET: \(key.name) [Domain: \(key.domain)]")
         try validateCatalogRegistration(for: key)
         try validatePlatformAvailability(for: key)
@@ -155,7 +155,7 @@ public actor StorageRouter: StorageProviding {
     /// - Parameter key: The storage key to retrieve.
     /// - Returns: The stored value.
     /// - Throws: `StorageError.notFound` if no value exists, plus domain-specific errors.
-    public func get<Key: StorageKey>(_ key: Key) async throws -> Key.Value {
+    public func get<Value>(_ key: StorageKey<Value>) async throws -> Value {
         Logger.debug(">>> [STORAGE] GET: \(key.name)")
         try validateCatalogRegistration(for: key)
         try validatePlatformAvailability(for: key)
@@ -182,7 +182,7 @@ public actor StorageRouter: StorageProviding {
     /// - Parameter key: The storage key to migrate.
     /// - Returns: The migration result.
     /// - Throws: Migration or storage errors.
-    public func forceMigration<Key: StorageKey>(for key: Key) async throws -> MigrationResult {
+    public func forceMigration<Value>(for key: StorageKey<Value>) async throws -> MigrationResult {
         Logger.debug(">>> [STORAGE] MANUAL MIGRATION: \(key.name)")
         try validateCatalogRegistration(for: key)
 
@@ -207,7 +207,7 @@ public actor StorageRouter: StorageProviding {
     /// Removes the value for the given key.
     /// - Parameter key: The storage key to remove.
     /// - Throws: Domain-specific errors if removal fails.
-    public func remove<Key: StorageKey>(_ key: Key) async throws {
+    public func remove<Value>(_ key: StorageKey<Value>) async throws {
         try validateCatalogRegistration(for: key)
         try validatePlatformAvailability(for: key)
         try await delete(for: .from(key))
@@ -216,7 +216,7 @@ public actor StorageRouter: StorageProviding {
     /// Checks if a value exists for the given key.
     /// - Parameter key: The storage key to check.
     /// - Returns: True if a value exists.
-    public func exists<Key: StorageKey>(_ key: Key) async throws -> Bool {
+    public func exists<Value>(_ key: StorageKey<Value>) async throws -> Bool {
         try validateCatalogRegistration(for: key)
         try validatePlatformAvailability(for: key)
         
@@ -265,7 +265,7 @@ public actor StorageRouter: StorageProviding {
     
     // MARK: - Platform Validation
     
-    nonisolated private func validatePlatformAvailability<Key: StorageKey>(for key: Key) throws {
+    nonisolated private func validatePlatformAvailability<Value>(for key: StorageKey<Value>) throws {
         #if os(watchOS)
         if key.availability == .phoneOnly {
             throw StorageError.phoneOnlyKeyAccessedOnWatch(key.name)
@@ -277,7 +277,7 @@ public actor StorageRouter: StorageProviding {
         #endif
     }
 
-    private func validateCatalogRegistration<Key: StorageKey>(for key: Key) throws {
+    private func validateCatalogRegistration<Value>(for key: StorageKey<Value>) throws {
         guard !registeredKeys.isEmpty else { return }
         guard registeredKeys[key.name] != nil else {
             let errorMessage = "UNREGISTERED STORAGE KEY: '\(key.name)' (Owner: \(key.owner)) accessed but not found in any registered catalog. Did you forget to call registerCatalog?"
@@ -331,7 +331,7 @@ public actor StorageRouter: StorageProviding {
 
     // MARK: - Migration
 
-    private func attemptMigration<Key: StorageKey>(for key: Key) async throws -> Key.Value? {
+    private func attemptMigration<Value>(for key: StorageKey<Value>) async throws -> Value? {
         guard let migration = resolveMigration(for: key) else { return nil }
 
         let context = buildMigrationContext()
@@ -354,7 +354,7 @@ public actor StorageRouter: StorageProviding {
         return nil
     }
 
-    private func resolveMigration<Key: StorageKey>(for key: Key) -> AnyStorageMigration? {
+    private func resolveMigration<Value>(for key: StorageKey<Value>) -> AnyStorageMigration? {
         key.migration
     }
 
@@ -366,8 +366,8 @@ public actor StorageRouter: StorageProviding {
         migrationHistory[descriptor.name] = Date()
     }
 
-    internal func shouldAllowMigration<Key: StorageKey>(
-        for key: Key,
+    internal func shouldAllowMigration<Value>(
+        for key: StorageKey<Value>,
         context: MigrationContext
     ) async throws -> Bool {
         guard key.availability.isAvailable(on: context.deviceInfo.platform) else {
@@ -440,7 +440,7 @@ public actor StorageRouter: StorageProviding {
     
     // MARK: - Storage Operations
     
-    private func store(_ data: Data, for key: any StorageKey) async throws {
+    private func store<Value>(_ data: Data, for key: StorageKey<Value>) async throws {
         try await store(data, for: .from(key))
     }
     
@@ -544,7 +544,7 @@ public actor StorageRouter: StorageProviding {
     
     // MARK: - Sync
     
-    private func handleSync(_ key: any StorageKey, data: Data) async throws {
+    private func handleSync<Value>(_ key: StorageKey<Value>, data: Data) async throws {
         try await sync.syncIfNeeded(
             data: data,
             keyName: key.name,