feat: add configurable external terminal launcher

Allows customizing the executable and arguments used by
Tools → Launch Copilot CLI (External Terminal) via a new VS Unified
Settings category (Settings → Copilot CLI IDE Bridge → External
Terminal). Defaults preserve existing behavior (`cmd.exe /k copilot`).

Supports any shell (`wt.exe`, `pwsh.exe`, `powershell.exe`, custom
path) and a `{WorkspaceFolder}` placeholder for terminals like Windows
Terminal that don't inherit the parent process working directory.
The resolved command/arguments/cwd are written to the Copilot CLI
output pane on launch for diagnostics.

Also:
- Rename existing Terminal settings category to "Embedded Terminal"
- Refactor TerminalSettings to share GetString/GetInt32 helpers
- Refactor TerminalSettingsProvider to derive moniker from key (ToMoniker)
  removing duplicate moniker constants

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: sailro

CHANGELOG.md

@@ -6,15 +6,24 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ## [Unreleased]
 
+## [1.0.19] - 2026-04-26
+
+### Added
+
+- **External terminal configuration** via VS Settings (**Settings → Copilot CLI IDE Bridge → External Terminal**) — customize the executable (`Command`) and `Arguments` used by **Tools → Launch Copilot CLI (External Terminal)**. Defaults preserve existing behavior (`cmd.exe /k copilot`); supports any shell (`wt.exe`, `pwsh.exe`, `powershell.exe`, or any executable on PATH / full path).
+- `{WorkspaceFolder}` placeholder in `Command` and `Arguments` — substituted with the current solution directory at launch time. Required for terminals that don't inherit the parent process working directory (e.g. `wt.exe -d "{WorkspaceFolder}" cmd /k copilot`).
+- Output pane log entry on external terminal launch showing the resolved command, arguments, and working directory — for debugging custom configurations.
+
 ### Changed
 
 - Replace `Task.Delay(200)` server startup wait with stdout `READY` handshake — deterministic server readiness detection with 10s timeout
+- Renamed the existing **Terminal** settings category to **Embedded Terminal** to disambiguate from the new External Terminal category.
 
 ### Fixed
 
 - Fix TOCTOU race condition in `DebouncePusher` — timer and key fields now properly synchronized
 - Clean up orphaned diff views on solution switch — `CleanupAllDiffs()` runs before RPC teardown in `StopConnection()`
-- Trim SSE event historyto last-per-notification-type — prevents unbounded growth from rapid selection/diagnostics changes while preserving initial state for new SSE clients
+- Trim SSE event history to last-per-notification-type — prevents unbounded growth from rapid selection/diagnostics changes while preserving initial state for new SSE clients
 - Remove no-op assertions and duplicate tests in server test suite
 
 ## [1.0.18] - 2026-04-13

README.md

@@ -42,7 +42,7 @@ Double-click the `.vsix` to install, or use F5 in Visual Studio to debug in the
 1. **Open a solution** in Visual Studio — the extension activates automatically
 2. **Launch Copilot CLI** using one of:
    - **Tools → Show Copilot CLI (Embedded Terminal)** — opens a dockable terminal inside VS with Copilot CLI running (native Microsoft.Terminal.Wpf control)
-   - **Tools → Launch Copilot CLI (External Terminal)** — opens Copilot CLI in an external terminal window
+   - **Tools → Launch Copilot CLI (External Terminal)** — opens Copilot CLI in an external terminal window. Configurable via **Settings → Copilot CLI IDE Bridge → External Terminal** (defaults to `cmd.exe /k copilot`; supports `wt.exe`, `pwsh.exe`, etc., with `{WorkspaceFolder}` placeholder).
    - Open a terminal manually in the solution folder
 3. **Run `/ide`** in Copilot CLI — it discovers Visual Studio and connects
 

src/CopilotCliIde/CopilotCliIdePackage.cs

@@ -281,11 +281,17 @@ private void OnLaunchCopilotCli(object sender, EventArgs e)
 		ThreadHelper.ThrowIfNotOnUIThread();
 		try
 		{
+			var workspaceFolder = GetWorkspaceFolder();
+			var fileName = ExpandPlaceholders(TerminalSettings.ExternalCommand, workspaceFolder);
+			var arguments = ExpandPlaceholders(TerminalSettings.ExternalArguments, workspaceFolder);
+
+			_logger?.Log($"Launching external terminal: \"{fileName}\" {arguments} (cwd: {workspaceFolder})");
+
 			Process.Start(new ProcessStartInfo
 			{
-				FileName = "cmd.exe",
-				Arguments = "/k copilot",
-				WorkingDirectory = GetWorkspaceFolder(),
+				FileName = fileName,
+				Arguments = arguments,
+				WorkingDirectory = workspaceFolder,
 				UseShellExecute = true
 			});
 		}
@@ -295,6 +301,16 @@ private void OnLaunchCopilotCli(object sender, EventArgs e)
 		}
 	}
 
+	// Replaces {WorkspaceFolder} with the current solution directory.
+	// Some terminals (e.g. wt.exe) ignore the parent process WorkingDirectory,
+	// so users can pass the folder explicitly via arguments.
+	private static string ExpandPlaceholders(string value, string workspaceFolder)
+	{
+		return string.IsNullOrEmpty(value)
+			? value
+			: value.Replace("{WorkspaceFolder}", workspaceFolder);
+	}
+
 	private void OnShowCopilotCliWindow(object sender, EventArgs e)
 	{
 		_ = JoinableTaskFactory.RunAsync(async () =>

src/CopilotCliIde/TerminalSettings.cs

@@ -9,41 +9,45 @@ internal static class TerminalSettings
 	public const string DefaultFontFamily = "Cascadia Code";
 	public const short DefaultFontSize = 12;
 
+	public const string DefaultExternalCommand = "cmd.exe";
+	public const string DefaultExternalArguments = "/k copilot";
+
 	private const string CollectionPath = "CopilotCliIde\\Terminal";
+	private const string ExternalCollectionPath = "CopilotCliIde\\ExternalTerminal";
+
+	public static string FontFamily => GetString(CollectionPath, TerminalSettingsProvider.FontFamilyKey, DefaultFontFamily);
+	public static short FontSize => (short)Math.Max(6, Math.Min(72, GetInt32(CollectionPath, TerminalSettingsProvider.FontSizeKey, DefaultFontSize)));
+	public static string ExternalCommand => GetString(ExternalCollectionPath, TerminalSettingsProvider.ExternalCommandKey, DefaultExternalCommand, requireNonBlank: true);
+	public static string ExternalArguments => GetString(ExternalCollectionPath, TerminalSettingsProvider.ExternalArgumentsKey, DefaultExternalArguments);
 
-	public static string FontFamily
+	private static string GetString(string collection, string key, string defaultValue, bool requireNonBlank = false)
 	{
-		get
+		try
 		{
-			try
+			var store = GetStore();
+			if (store != null && store.CollectionExists(collection) && store.PropertyExists(collection, key))
 			{
-				var store = GetStore();
-				if (store != null && store.CollectionExists(CollectionPath) && store.PropertyExists(CollectionPath, TerminalSettingsProvider.FontFamilyKey))
-					return store.GetString(CollectionPath, TerminalSettingsProvider.FontFamilyKey);
+				var value = store.GetString(collection, key);
+				if (!requireNonBlank || !string.IsNullOrWhiteSpace(value))
+					return value;
 			}
-			catch { /* Ignore */ }
-
-			return DefaultFontFamily;
 		}
+		catch { /* Ignore */ }
+
+		return defaultValue;
 	}
 
-	public static short FontSize
+	private static int GetInt32(string collection, string key, int defaultValue)
 	{
-		get
+		try
 		{
-			try
-			{
-				var store = GetStore();
-				if (store != null && store.CollectionExists(CollectionPath) && store.PropertyExists(CollectionPath, TerminalSettingsProvider.FontSizeKey))
-				{
-					var size = store.GetInt32(CollectionPath, TerminalSettingsProvider.FontSizeKey);
-					return (short)Math.Max(6, Math.Min(72, size));
-				}
-			}
-			catch { /* Ignore */ }
-
-			return DefaultFontSize;
+			var store = GetStore();
+			if (store != null && store.CollectionExists(collection) && store.PropertyExists(collection, key))
+				return store.GetInt32(collection, key);
 		}
+		catch { /* Ignore */ }
+
+		return defaultValue;
 	}
 
 	private static WritableSettingsStore? GetStore()

src/CopilotCliIde/TerminalSettingsProvider.cs

@@ -11,10 +11,11 @@ internal sealed class TerminalSettingsProvider : IExternalSettingsProvider
 	public const string ServiceGuid = "b2c3d4e5-f6a7-4b8c-9d0e-1f2a3b4c5d6e";
 
 	private const string CollectionPath = "CopilotCliIde\\Terminal";
+	private const string ExternalCollectionPath = "CopilotCliIde\\ExternalTerminal";
 	public const string FontFamilyKey = "FontFamily";
 	public const string FontSizeKey = "FontSize";
-	private const string FontFamilyMoniker = "fontFamily";
-	private const string FontSizeMoniker = "fontSize";
+	public const string ExternalCommandKey = "Command";
+	public const string ExternalArgumentsKey = "Arguments";
 
 	private readonly WritableSettingsStore _store;
 
@@ -30,24 +31,45 @@ public TerminalSettingsProvider(WritableSettingsStore store)
 		_store = store;
 		if (!_store.CollectionExists(CollectionPath))
 			_store.CreateCollection(CollectionPath);
+		if (!_store.CollectionExists(ExternalCollectionPath))
+			_store.CreateCollection(ExternalCollectionPath);
 	}
 
+	// Monikers in registration.json mirror the storage keys with a lowercase first letter
+	// (e.g. "FontFamily" -> "fontFamily"). Treat them as the same identifier in two casings.
+	private static string ToMoniker(string key) => char.ToLowerInvariant(key[0]) + key.Substring(1);
+
+	private static bool Matches(string moniker, string key)
+		=> moniker.EndsWith(ToMoniker(key), StringComparison.OrdinalIgnoreCase);
+
 	public Task<ExternalSettingOperationResult<T>> GetValueAsync<T>(string moniker, CancellationToken cancellationToken) where T : notnull
 	{
 		object? value = null;
 
-		if (moniker.EndsWith(FontFamilyMoniker, StringComparison.OrdinalIgnoreCase))
+		if (Matches(moniker, FontFamilyKey))
 		{
 			value = _store.PropertyExists(CollectionPath, FontFamilyKey)
 				? _store.GetString(CollectionPath, FontFamilyKey)
 				: TerminalSettings.DefaultFontFamily;
 		}
-		else if (moniker.EndsWith(FontSizeMoniker, StringComparison.OrdinalIgnoreCase))
+		else if (Matches(moniker, FontSizeKey))
 		{
 			value = _store.PropertyExists(CollectionPath, FontSizeKey)
 				? _store.GetInt32(CollectionPath, FontSizeKey)
 				: TerminalSettings.DefaultFontSize;
 		}
+		else if (Matches(moniker, ExternalCommandKey))
+		{
+			value = _store.PropertyExists(ExternalCollectionPath, ExternalCommandKey)
+				? _store.GetString(ExternalCollectionPath, ExternalCommandKey)
+				: TerminalSettings.DefaultExternalCommand;
+		}
+		else if (Matches(moniker, ExternalArgumentsKey))
+		{
+			value = _store.PropertyExists(ExternalCollectionPath, ExternalArgumentsKey)
+				? _store.GetString(ExternalCollectionPath, ExternalArgumentsKey)
+				: TerminalSettings.DefaultExternalArguments;
+		}
 
 		return value is not null
 			? ExternalSettingOperationResult.SuccessResultTask((T)value)
@@ -56,14 +78,22 @@ public Task<ExternalSettingOperationResult<T>> GetValueAsync<T>(string moniker,
 
 	public Task<ExternalSettingOperationResult> SetValueAsync<T>(string moniker, T value, CancellationToken cancellationToken) where T : notnull
 	{
-		if (moniker.EndsWith(FontFamilyMoniker, StringComparison.OrdinalIgnoreCase) && value is string s)
+		if (Matches(moniker, FontFamilyKey) && value is string s)
 		{
 			_store.SetString(CollectionPath, FontFamilyKey, s);
 		}
-		else if (moniker.EndsWith(FontSizeMoniker, StringComparison.OrdinalIgnoreCase) && value is int i)
+		else if (Matches(moniker, FontSizeKey) && value is int i)
 		{
 			_store.SetInt32(CollectionPath, FontSizeKey, Math.Max(6, Math.Min(72, i)));
 		}
+		else if (Matches(moniker, ExternalCommandKey) && value is string cmd)
+		{
+			_store.SetString(ExternalCollectionPath, ExternalCommandKey, cmd);
+		}
+		else if (Matches(moniker, ExternalArgumentsKey) && value is string args)
+		{
+			_store.SetString(ExternalCollectionPath, ExternalArgumentsKey, args);
+		}
 		else
 		{
 			return Task.FromResult<ExternalSettingOperationResult>(
@@ -75,7 +105,7 @@ public Task<ExternalSettingOperationResult> SetValueAsync<T>(string moniker, T v
 
 	public async Task<ExternalSettingOperationResult<IReadOnlyList<EnumChoice>>> GetEnumChoicesAsync(string enumSettingMoniker, CancellationToken cancellationToken)
 	{
-		if (!enumSettingMoniker.EndsWith(FontFamilyMoniker, StringComparison.OrdinalIgnoreCase))
+		if (!Matches(enumSettingMoniker, FontFamilyKey))
 			return ExternalSettingOperationResult.SuccessResult<IReadOnlyList<EnumChoice>>([]);
 
 		await Task.Yield();

src/CopilotCliIde/registration.json

@@ -4,14 +4,28 @@
       "title": "Copilot CLI IDE Bridge"
     },
     "copilotCliIde.terminal": {
-      "title": "Terminal",
+      "title": "Embedded Terminal",
       "order": 1
+    },
+    "copilotCliIde.externalTerminal": {
+      "title": "External Terminal",
+      "order": 2,
+      "messages": [
+        {
+          "text": "The external terminal is launched in the working directory of the current solution. Use the {WorkspaceFolder} placeholder in Command or Arguments when a terminal (like Windows Terminal) does not inherit the working directory.",
+          "severity": "informational"
+        },
+        {
+          "text": "Examples — cmd.exe: '/k copilot'  •  wt.exe: '-d \"{WorkspaceFolder}\" cmd /k copilot'  •  pwsh.exe: '-NoExit -Command copilot'  •  powershell.exe: '-NoExit -Command copilot'",
+          "severity": "informational"
+        }
+      ]
     }
   },
   "properties": {
     "copilotCliIde.terminal.externalSettings": {
       "type": "external",
-      "title": "Terminal",
+      "title": "Embedded Terminal",
       "backingStoreDescription": "Stored in Visual Studio settings.",
       "callback": {
         "packageId": "a1b2c3d4-e5f6-4a5b-8c9d-0e1f2a3b4c5d",
@@ -32,6 +46,28 @@
           "description": "Font size (in points) used for the embedded terminal."
         }
       }
+    },
+    "copilotCliIde.externalTerminal.externalSettings": {
+      "type": "external",
+      "title": "External Terminal",
+      "backingStoreDescription": "Stored in Visual Studio settings.",
+      "callback": {
+        "packageId": "a1b2c3d4-e5f6-4a5b-8c9d-0e1f2a3b4c5d",
+        "serviceId": "b2c3d4e5-f6a7-4b8c-9d0e-1f2a3b4c5d6e"
+      },
+      "realtimeNotifications": true,
+      "properties": {
+        "command": {
+          "type": "string",
+          "title": "Command",
+          "description": "Executable used to launch Copilot CLI from the Tools menu. Any executable on PATH or full path is accepted. Common shells: cmd.exe, powershell.exe, pwsh.exe, wt.exe."
+        },
+        "arguments": {
+          "type": "string",
+          "title": "Arguments",
+          "description": "Arguments passed to the command. Use {WorkspaceFolder} to substitute the current solution directory. Examples: cmd.exe → '/k copilot'; wt.exe → '-d \"{WorkspaceFolder}\" cmd /k copilot'; pwsh.exe → '-NoExit -Command copilot'."
+        }
+      }
     }
   }
 }