diff --git a/Sources/ConsoleKitCommands/Async/AsyncCommand.swift b/Sources/ConsoleKitCommands/Async/AsyncCommand.swift
index eabce96..8eeb8da 100644
--- a/Sources/ConsoleKitCommands/Async/AsyncCommand.swift
+++ b/Sources/ConsoleKitCommands/Async/AsyncCommand.swift
@@ -80,7 +80,7 @@ import ConsoleKitTerminal
 ///                     U  ||----w |
 ///                        ||     ||
 ///
-public protocol AsyncCommand: AnyAsyncCommand {
+public protocol AsyncCommand: Sendable, AnyAsyncCommand {
     associatedtype Signature: CommandSignature
     func run(using context: CommandContext, signature: Signature) async throws
 }
@@ -91,7 +91,7 @@ extension AsyncCommand {
         guard context.input.arguments.isEmpty else {
             throw CommandError.unknownInput(context.input.arguments.joined(separator: " "))
         }
-      try await self.run(using: context, signature: signature)
+        try await self.run(using: context, signature: signature)
     }
 
     public func outputAutoComplete(using context: inout CommandContext) {
@@ -102,7 +102,10 @@ extension AsyncCommand {
     }
 
     public func outputHelp(using context: inout CommandContext) {
-        context.console.output("Usage: ".consoleText(.info) + context.input.executable.consoleText() + " ", newLine: false)
+        context.console.output(
+            "Usage: ".consoleText(.info) + context.input.executable.consoleText() + " ",
+            newLine: false
+        )
         Signature().outputHelp(help: self.help, using: &context)
     }
 }
diff --git a/Sources/ConsoleKitCommands/Async/AsyncCommandGroup.swift b/Sources/ConsoleKitCommands/Async/AsyncCommandGroup.swift
index e43254d..a90a87a 100644
--- a/Sources/ConsoleKitCommands/Async/AsyncCommandGroup.swift
+++ b/Sources/ConsoleKitCommands/Async/AsyncCommandGroup.swift
@@ -18,11 +18,41 @@ import ConsoleKitTerminal
 public protocol AsyncCommandGroup: AnyAsyncCommand {
     var commands: [String: any AnyAsyncCommand] { get }
     var defaultCommand: (any AnyAsyncCommand)? { get }
+
+    /// Merges this group with another group.
+    /// - Parameters:
+    ///   - group: The group to merge with.
+    ///   - defaultCommand: The new default command to use.
+    ///   - help: The help message to use for the merged group.
+    /// - Returns: A new `AsyncCommandGroup` with the merged commands.
+    func merge(
+        with group: any AsyncCommandGroup,
+        defaultCommand: (any AnyAsyncCommand)?,
+        help: String
+    ) -> any AsyncCommandGroup
+}
+
+public struct MergedAsyncCommandGroup: AsyncCommandGroup {
+    public let commands: [String: any AnyAsyncCommand]
+    public let defaultCommand: (any AnyAsyncCommand)?
+    public var help: String
 }
 
 extension AsyncCommandGroup {
-    public var defaultCommand: (any AnyAsyncCommand)? {
-        nil
+    public var defaultCommand: (any AnyAsyncCommand)? { nil }
+
+    public func merge(
+        with group: any AsyncCommandGroup,
+        defaultCommand: (any AnyAsyncCommand)?,
+        help: String
+    ) -> any AsyncCommandGroup {
+        var mergedCommands = self.commands
+        mergedCommands.merge(group.commands, uniquingKeysWith: { (_, new) in new })
+        return MergedAsyncCommandGroup(
+            commands: mergedCommands,
+            defaultCommand: defaultCommand,
+            help: help
+        )
     }
 }
 
diff --git a/Sources/ConsoleKitCommands/Async/AsyncCommands.swift b/Sources/ConsoleKitCommands/Async/AsyncCommands.swift
index e0501a2..76e598a 100644
--- a/Sources/ConsoleKitCommands/Async/AsyncCommands.swift
+++ b/Sources/ConsoleKitCommands/Async/AsyncCommands.swift
@@ -1,5 +1,5 @@
 /// Represents a top-level group of configured commands. This is usually created by calling `resolve(for:)` on `AsyncCommands`.
-public struct AsyncCommands {
+public struct AsyncCommands: Sendable {
     /// Top-level available commands, stored by unique name.
     public var commands: [String: any AnyAsyncCommand]
 
@@ -38,7 +38,7 @@ public struct AsyncCommands {
         self.defaultCommand = defaultCommand
         self.enableAutocomplete = enableAutocomplete
     }
-    
+
     /// Adds an `AsyncCommand` instance to the config.
     ///
     ///     var config = AsyncCommands()
diff --git a/Sources/ConsoleKitCommands/Base/AnyCommand.swift b/Sources/ConsoleKitCommands/Base/AnyCommand.swift
index 28fbe8f..84ab2bb 100644
--- a/Sources/ConsoleKitCommands/Base/AnyCommand.swift
+++ b/Sources/ConsoleKitCommands/Base/AnyCommand.swift
@@ -1,8 +1,8 @@
 /// A type-erased `Command`.
-public protocol AnyCommand: Sendable {
+public protocol AnyCommand: Sendable, AnyAsyncCommand {
     /// Text that will be displayed when `--help` is passed.
     var help: String { get }
-    
+
     /// Runs the command against the supplied input.
     func run(using context: inout CommandContext) throws
     func outputAutoComplete(using context: inout CommandContext) throws
@@ -24,4 +24,13 @@ extension AnyCommand {
     public func renderCompletionFunctions(using context: CommandContext, shell: Shell) -> String {
         ""
     }
+
+    // we need to have a sync environment so the compiler uses the sync run method over the async version
+    private func syncRun(using context: inout CommandContext) throws {
+        try self.run(using: &context)
+    }
+
+    public func run(using context: inout CommandContext) async throws {
+        try self.syncRun(using: &context)
+    }
 }
diff --git a/Sources/ConsoleKitCommands/Base/CommandContext.swift b/Sources/ConsoleKitCommands/Base/CommandContext.swift
index d12696b..7fcbdd5 100644
--- a/Sources/ConsoleKitCommands/Base/CommandContext.swift
+++ b/Sources/ConsoleKitCommands/Base/CommandContext.swift
@@ -1,15 +1,16 @@
 import protocol ConsoleKitTerminal.Console
+import struct ConsoleKitTerminal.AnySendableHashable
 
 /// A type-erased `CommandContext`
-public struct CommandContext {
+public struct CommandContext: Sendable {
     /// The `Console` this command was run on.
     public var console: any Console
-    
+
     /// The parsed arguments (according to declared signature).
     public var input: CommandInput
 
-    public var userInfo: [AnyHashable: Any]
-    
+    public var userInfo: [AnySendableHashable: any Sendable]
+
     /// Create a new `AnyCommandContext`.
     public init(
         console: any Console,
diff --git a/Sources/ConsoleKitCommands/Base/CommandGroup.swift b/Sources/ConsoleKitCommands/Base/CommandGroup.swift
index 3be82c7..b838590 100644
--- a/Sources/ConsoleKitCommands/Base/CommandGroup.swift
+++ b/Sources/ConsoleKitCommands/Base/CommandGroup.swift
@@ -15,7 +15,7 @@ import ConsoleKitTerminal
 ///     try console.run(group, with: context)
 ///
 /// You can create your own `CommandGroup` if you want to support custom `CommandOptions`.
-public protocol CommandGroup: AnyCommand {
+public protocol CommandGroup: AnyCommand, AsyncCommandGroup {
     var commands: [String: any AnyCommand] { get }
     var defaultCommand: (any AnyCommand)? { get }
 }
@@ -24,6 +24,12 @@ extension CommandGroup {
     public var defaultCommand: (any AnyCommand)? {
         nil
     }
+
+    public var commands: [String: any AnyAsyncCommand] {
+        // make the compiler happy
+        let castedCommands: [String: any AnyCommand] = commands
+        return castedCommands
+    }
 }
 
 extension CommandGroup {