diff --git a/pkgs/dart_mcp_server/CHANGELOG.md b/pkgs/dart_mcp_server/CHANGELOG.md
index 3802d73..107ce79 100644
--- a/pkgs/dart_mcp_server/CHANGELOG.md
+++ b/pkgs/dart_mcp_server/CHANGELOG.md
@@ -18,6 +18,8 @@
 * Fix a bug in hot_reload ([#290](https://github.com/dart-lang/ai/issues/290)).
 * Add the `list_devices`, `launch_app`, `get_app_logs`, and `list_running_apps`
   tools for running Flutter apps.
+* Add extra log output to failed launches, and allow AI to specify the maxLines
+  of log output.
 
 # 0.1.0 (Dart SDK 3.9.0)
 
diff --git a/pkgs/dart_mcp_server/lib/src/mixins/flutter_launcher.dart b/pkgs/dart_mcp_server/lib/src/mixins/flutter_launcher.dart
index afd8d6f..01c9651 100644
--- a/pkgs/dart_mcp_server/lib/src/mixins/flutter_launcher.dart
+++ b/pkgs/dart_mcp_server/lib/src/mixins/flutter_launcher.dart
@@ -8,6 +8,7 @@ library;
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
+import 'dart:math' as math;
 
 import 'package:dart_mcp/server.dart';
 
@@ -170,13 +171,21 @@ base mixin FlutterLauncherSupport
             LoggingLevel.info,
             'Flutter application ${process!.pid} exited with code $exitCode.',
           );
-          _runningApps.remove(process.pid);
           if (!completer.isCompleted) {
+            final logs = _runningApps[process.pid]?.logs ?? [];
+            // Only output the last 500 lines of logs.
+            final startLine = math.max(0, logs.length - 500);
+            final logOutput = [
+              if (startLine > 0) '[skipping $startLine log lines]...',
+              ...logs.sublist(startLine),
+            ];
             completer.completeError(
               'Flutter application exited with code $exitCode before the DTD '
-              'URI was found.',
+              'URI was found, with log output:\n${logOutput.join('\n')}',
             );
           }
+          _runningApps.remove(process.pid);
+
           // Cancel subscriptions after all processing is done.
           await stdoutSubscription.cancel();
           await stderrSubscription.cancel();
@@ -360,6 +369,11 @@ base mixin FlutterLauncherSupport
               'The process ID of the flutter run process running the '
               'application.',
         ),
+        'maxLines': Schema.int(
+          description:
+              'The maximum number of log lines to return from the end of the '
+              'logs. Defaults to 500. If set to -1, all logs will be returned.',
+        ),
       },
       required: ['pid'],
     ),
@@ -376,8 +390,9 @@ base mixin FlutterLauncherSupport
 
   Future<CallToolResult> _getAppLogs(CallToolRequest request) async {
     final pid = request.arguments!['pid'] as int;
+    var maxLines = request.arguments!['maxLines'] as int? ?? 500;
     log(LoggingLevel.info, 'Getting logs for application with PID: $pid');
-    final logs = _runningApps[pid]?.logs;
+    var logs = _runningApps[pid]?.logs;
 
     if (logs == null) {
       log(
@@ -394,6 +409,17 @@ base mixin FlutterLauncherSupport
       );
     }
 
+    if (maxLines == -1) {
+      maxLines = logs.length;
+    }
+    if (maxLines > 0 && maxLines <= logs.length) {
+      final startLine = logs.length - maxLines;
+      logs = [
+        if (startLine > 0) '[skipping $startLine log lines]...',
+        ...logs.sublist(startLine),
+      ];
+    }
+
     return CallToolResult(
       content: [TextContent(text: logs.join('\n'))],
       structuredContent: {'logs': logs},
diff --git a/pkgs/dart_mcp_server/test/tools/flutter_launcher_test.dart b/pkgs/dart_mcp_server/test/tools/flutter_launcher_test.dart
index 7ec8b5e..43666dd 100644
--- a/pkgs/dart_mcp_server/test/tools/flutter_launcher_test.dart
+++ b/pkgs/dart_mcp_server/test/tools/flutter_launcher_test.dart
@@ -197,6 +197,285 @@ void main() {
         await client.shutdown();
       },
     );
+
+    test.test('launch_app tool fails when process exits early', () async {
+      final mockProcessManager = MockProcessManager();
+      mockProcessManager.addCommand(
+        Command(
+          [
+            Platform.isWindows
+                ? r'C:\path\to\flutter\sdk\bin\cache\dart-sdk\bin\dart.exe'
+                : '/path/to/flutter/sdk/bin/cache/dart-sdk/bin/dart',
+            'language-server',
+            '--protocol',
+            'lsp',
+          ],
+          stdout:
+              '''Content-Length: 145\r\n\r\n{"jsonrpc":"2.0","id":0,"result":{"capabilities":{"workspace":{"workspaceFolders":{"supported":true,"changeNotifications":true}},"workspaceSymbolProvider":true}}}''',
+        ),
+      );
+      mockProcessManager.addCommand(
+        Command(
+          [
+            Platform.isWindows
+                ? r'C:\path\to\flutter\sdk\bin\flutter.bat'
+                : '/path/to/flutter/sdk/bin/flutter',
+            'run',
+            '--print-dtd',
+            '--device-id',
+            'test-device',
+          ],
+          stderr: 'Something went wrong',
+          exitCode: Future.value(1),
+        ),
+      );
+      final serverAndClient = await createServerAndClient(
+        processManager: mockProcessManager,
+        fileSystem: fileSystem,
+      );
+      final server = serverAndClient.server;
+      final client = serverAndClient.client;
+
+      // Initialize
+      await client.initialize(
+        InitializeRequest(
+          protocolVersion: ProtocolVersion.latestSupported,
+          capabilities: ClientCapabilities(),
+          clientInfo: Implementation(name: 'test_client', version: '1.0.0'),
+        ),
+      );
+      client.notifyInitialized();
+
+      // Call the tool
+      final result = await client.callTool(
+        CallToolRequest(
+          name: 'launch_app',
+          arguments: {'root': projectRoot, 'device': 'test-device'},
+        ),
+      );
+
+      test.expect(result.isError, true);
+      final textOutput = result.content as List<TextContent>;
+      test.expect(
+        textOutput.map((context) => context.text).toList().join('\n'),
+        test.stringContainsInOrder([
+          'Flutter application exited with code 1 before the DTD URI was found',
+          'with log output',
+          'Something went wrong',
+        ]),
+      );
+      await server.shutdown();
+      await client.shutdown();
+    });
+
+    test.test('stop_app tool stops a running app', () async {
+      final dtdUri = 'ws://127.0.0.1:12345/abcdefg=';
+      final processPid = 54321;
+      final mockProcessManager = MockProcessManager();
+      mockProcessManager.addCommand(
+        Command(
+          [
+            Platform.isWindows
+                ? r'C:\path\to\flutter\sdk\bin\cache\dart-sdk\bin\dart.exe'
+                : '/path/to/flutter/sdk/bin/cache/dart-sdk/bin/dart',
+            'language-server',
+            '--protocol',
+            'lsp',
+          ],
+          stdout:
+              '''Content-Length: 145\r\n\r\n{"jsonrpc":"2.0","id":0,"result":{"capabilities":{"workspace":{"workspaceFolders":{"supported":true,"changeNotifications":true}},"workspaceSymbolProvider":true}}}
+''',
+        ),
+      );
+      mockProcessManager.addCommand(
+        Command(
+          [
+            Platform.isWindows
+                ? r'C:\path\to\flutter\sdk\bin\flutter.bat'
+                : '/path/to/flutter/sdk/bin/flutter',
+            'run',
+            '--print-dtd',
+            '--device-id',
+            'test-device',
+          ],
+          stdout: 'The Dart Tooling Daemon is available at: $dtdUri\n',
+          pid: processPid,
+        ),
+      );
+      final serverAndClient = await createServerAndClient(
+        processManager: mockProcessManager,
+        fileSystem: fileSystem,
+      );
+      final server = serverAndClient.server;
+      final client = serverAndClient.client;
+
+      // Initialize and launch the app
+      await client.initialize(
+        InitializeRequest(
+          protocolVersion: ProtocolVersion.latestSupported,
+          capabilities: ClientCapabilities(),
+          clientInfo: Implementation(name: 'test_client', version: '1.0.0'),
+        ),
+      );
+      client.notifyInitialized();
+      await client.callTool(
+        CallToolRequest(
+          name: 'launch_app',
+          arguments: {'root': projectRoot, 'device': 'test-device'},
+        ),
+      );
+
+      // Stop the app
+      final result = await client.callTool(
+        CallToolRequest(name: 'stop_app', arguments: {'pid': processPid}),
+      );
+
+      test.expect(result.isError, test.isNot(true));
+      test.expect(result.structuredContent, {'success': true});
+      test.expect(mockProcessManager.killedPids, [processPid]);
+      await server.shutdown();
+      await client.shutdown();
+    });
+
+    test.test('get_app_logs tool respects maxLines', () async {
+      final dtdUri = 'ws://127.0.0.1:12345/abcdefg=';
+      final processPid = 54321;
+      final mockProcessManager = MockProcessManager();
+      mockProcessManager.addCommand(
+        Command(
+          [
+            Platform.isWindows
+                ? r'C:\path\to\flutter\sdk\bin\cache\dart-sdk\bin\dart.exe'
+                : '/path/to/flutter/sdk/bin/cache/dart-sdk/bin/dart',
+            'language-server',
+            '--protocol',
+            'lsp',
+          ],
+          stdout:
+              '''Content-Length: 145\r\n\r\n{"jsonrpc":"2.0","id":0,"result":{"capabilities":{"workspace":{"workspaceFolders":{"supported":true,"changeNotifications":true}},"workspaceSymbolProvider":true}}}''',
+        ),
+      );
+      mockProcessManager.addCommand(
+        Command(
+          [
+            Platform.isWindows
+                ? r'C:\path\to\flutter\sdk\bin\flutter.bat'
+                : '/path/to/flutter/sdk/bin/flutter',
+            'run',
+            '--print-dtd',
+            '--device-id',
+            'test-device',
+          ],
+          stdout:
+              'line 1\nline 2\nline 3\n'
+              'The Dart Tooling Daemon is available at: $dtdUri\n',
+          pid: processPid,
+        ),
+      );
+      final serverAndClient = await createServerAndClient(
+        processManager: mockProcessManager,
+        fileSystem: fileSystem,
+      );
+      final server = serverAndClient.server;
+      final client = serverAndClient.client;
+
+      // Initialize and launch the app
+      await client.initialize(
+        InitializeRequest(
+          protocolVersion: ProtocolVersion.latestSupported,
+          capabilities: ClientCapabilities(),
+          clientInfo: Implementation(name: 'test_client', version: '1.0.0'),
+        ),
+      );
+      client.notifyInitialized();
+      await client.callTool(
+        CallToolRequest(
+          name: 'launch_app',
+          arguments: {'root': projectRoot, 'device': 'test-device'},
+        ),
+      );
+
+      // Get the logs
+      final result = await client.callTool(
+        CallToolRequest(
+          name: 'get_app_logs',
+          arguments: {'pid': processPid, 'maxLines': 2},
+        ),
+      );
+
+      test.expect(result.isError, test.isNot(true));
+      test.expect(result.structuredContent, {
+        'logs': [
+          '[skipping 2 log lines]...',
+          '[stdout] line 3',
+          '[stdout] The Dart Tooling Daemon is available at: ws://127.0.0.1:12345/abcdefg=',
+        ],
+      });
+      await server.shutdown();
+      await client.shutdown();
+    });
+
+    test.test('list_devices tool returns available devices', () async {
+      final mockProcessManager = MockProcessManager();
+      mockProcessManager.addCommand(
+        Command(
+          [
+            Platform.isWindows
+                ? r'C:\path\to\flutter\sdk\bin\cache\dart-sdk\bin\dart.exe'
+                : '/path/to/flutter/sdk/bin/cache/dart-sdk/bin/dart',
+            'language-server',
+            '--protocol',
+            'lsp',
+          ],
+          stdout:
+              '''Content-Length: 145\r\n\r\n{"jsonrpc":"2.0","id":0,"result":{"capabilities":{"workspace":{"workspaceFolders":{"supported":true,"changeNotifications":true}},"workspaceSymbolProvider":true}}}
+''',
+        ),
+      );
+      mockProcessManager.addCommand(
+        Command(
+          [
+            Platform.isWindows
+                ? r'C:\path\to\flutter\sdk\bin\flutter.bat'
+                : '/path/to/flutter/sdk/bin/flutter',
+            'devices',
+            '--machine',
+          ],
+          stdout: jsonEncode([
+            {'id': 'test-device-1'},
+            {'id': 'test-device-2'},
+          ]),
+        ),
+      );
+      final serverAndClient = await createServerAndClient(
+        processManager: mockProcessManager,
+        fileSystem: fileSystem,
+      );
+      final server = serverAndClient.server;
+      final client = serverAndClient.client;
+
+      // Initialize
+      await client.initialize(
+        InitializeRequest(
+          protocolVersion: ProtocolVersion.latestSupported,
+          capabilities: ClientCapabilities(),
+          clientInfo: Implementation(name: 'test_client', version: '1.0.0'),
+        ),
+      );
+      client.notifyInitialized();
+
+      // List devices
+      final result = await client.callTool(
+        CallToolRequest(name: 'list_devices', arguments: {}),
+      );
+
+      test.expect(result.isError, test.isNot(true));
+      test.expect(result.structuredContent, {
+        'devices': ['test-device-1', 'test-device-2'],
+      });
+      await server.shutdown();
+      await client.shutdown();
+    });
   });
 }