feat: add custom MCP (#1416)

* feat: init mcp

* refactor: refactored MCP server to use VeryGoodCommandRunner and minor label fixes

* chore: expand tool descriptions and input schema details

* feat: fixed create tool description and arguments

* feat: fixed test tool description and arguments

* fix: changed some create arguments descriptions

* fix: improved some descriptions

* fix: doc and fix tests

* fix: test coverage for mcp_command

* fix: test coverage for mcp_command

* fix: tests and coverage for mcp_server

* fix: exclude-covereage fix and test coverage

* fix: fixed exclude_coverage schema

* chore: removed unreachable exception blocks in each handle command

* refactor: extract cliArgs to improve readability

* chore: rename packages_check tool to packages_check_licenses and minor improvements

* chore: remove unnecessary comments in mcp_server.dart

* chore: remove unnecessary comments about stream_channel dependency

* chore: update MCP tool names and links in README

* chore: added experimental warning for mcp at README

* fix: added experimental warning message to cli help

---------

Co-authored-by: Dominik Simonik <[email protected]>
Co-authored-by: RuiAlonso <[email protected]>

Author: 3 people

README.md

@@ -177,6 +177,26 @@ very_good packages check licenses --forbidden="unknown"
 very_good packages check licenses --dependency-type="direct-main,transitive"
 ```
 
+### [`very_good mcp`](https://cli.vgv.dev/docs/commands/mcp)
+
+Start the MCP (Model Context Protocol) server for AI assistant integration.
+
+> ℹ️ **Experimental**  
+> This command relies on the [Dart MCP Server](https://docs.flutter.dev/ai/mcp-server). This is an experimental package and may change or become unstable without notice. Use it with caution at your own risk.
+
+```sh
+# Start the MCP server
+very_good mcp
+```
+
+The MCP server exposes Very Good CLI functionality through the Model Context Protocol, allowing AI assistants to interact with the CLI programmatically. This enables automated project creation, testing, and package management through MCP-compatible tools.
+
+**Available MCP Tools:**
+- `create`: Create new Dart/Flutter projects (https://cli.vgv.dev/docs/category/templates)
+- `tests`: Run tests with optional coverage and optimization (https://cli.vgv.dev/docs/commands/test)
+- `packages_check_licenses`: Check packages for issues and licenses (https://cli.vgv.dev/docs/commands/check_licenses)
+- `packages_get`: Get package information and dependencies (https://cli.vgv.dev/docs/commands/get_pkgs)
+
 ### [`very_good --help`](https://cli.vgv.dev/docs/overview)
 
 See the complete list of commands and usage information.
@@ -194,6 +214,7 @@ Global options:
 Available commands:
   create     very_good create <subcommand> <project-name> [arguments]
              Creates a new very good project in the specified directory.
+  mcp        Start the MCP (Model Context Protocol) server. WARNING: This is an experimental package and may change or become unstable without notice. Use it with caution at your own risk.
   packages   Command for managing packages.
   test       Run tests in a Dart or Flutter project.
   update     Update Very Good CLI.

bin/very_good.dart

@@ -8,6 +8,7 @@ import 'package:pub_updater/pub_updater.dart';
 import 'package:universal_io/io.dart';
 import 'package:very_good_cli/src/commands/commands.dart';
 import 'package:very_good_cli/src/logger_extension.dart';
+import 'package:very_good_cli/src/mcp/mcp.dart';
 import 'package:very_good_cli/src/version.dart';
 
 /// The package name.
@@ -37,6 +38,7 @@ class VeryGoodCommandRunner extends CompletionCommandRunner<int> {
     addCommand(TestCommand(logger: _logger));
     addCommand(UpdateCommand(logger: _logger, pubUpdater: pubUpdater));
     addCommand(DartCommand(logger: _logger));
+    addCommand(MCPCommand(logger: _logger));
   }
 
   /// Standard timeout duration for the CLI.

lib/src/command_runner.dart

@@ -0,0 +1,2 @@
+export 'mcp_command.dart';
+export 'mcp_server.dart';

lib/src/mcp/mcp.dart

@@ -0,0 +1,104 @@
+import 'dart:async';
+import 'dart:io';
+
+import 'package:args/command_runner.dart';
+import 'package:dart_mcp/server.dart';
+import 'package:dart_mcp/stdio.dart';
+import 'package:mason/mason.dart';
+import 'package:stream_channel/stream_channel.dart';
+import 'package:very_good_cli/src/mcp/mcp_server.dart';
+
+/// Type definition for a factory that creates a [VeryGoodMCPServer].
+typedef ServerFactory =
+    MCPServer Function({
+      required StreamChannel<String> channel,
+      required Logger logger,
+    });
+
+/// Factory function to create a [StreamChannel] from input and output streams.
+typedef ChannelFactory = StreamChannel<String> Function();
+
+// Private default implementation for the channel factory
+StreamChannel<String> _defaultChannelFactory() {
+  return stdioChannel(input: stdin, output: stdout);
+}
+
+/// {@template mcp_command}
+/// `very_good mcp` command starts the MCP (Model Context Protocol) server.
+/// {@endtemplate}
+class MCPCommand extends Command<int> {
+  /// {@macro mcp_command}
+  MCPCommand({
+    Logger? logger,
+    ChannelFactory? channelFactory,
+    ServerFactory? serverFactory,
+  }) : _logger = logger ?? Logger(),
+       _channelFactory = channelFactory ?? _defaultChannelFactory,
+       _serverFactory = serverFactory ?? VeryGoodMCPServer.new;
+
+  /// The [name] of the command. But static.
+  static const String commandName = 'mcp';
+
+  @override
+  String get description => '''
+Start the MCP (Model Context Protocol) server. WARNING: This is an experimental package and may change or become unstable without notice. Use it with caution at your own risk.''';
+
+  @override
+  String get name => commandName;
+
+  final Logger _logger;
+
+  final ChannelFactory _channelFactory;
+
+  final ServerFactory _serverFactory;
+
+  @override
+  Future<int> run() async {
+    try {
+      _logger
+        ..info('Starting Very Good CLI MCP Server...')
+        ..info(
+          'Server will listen on stdin/stdout for MCP protocol messages',
+        );
+
+      // Create a channel from stdin/stdout using the stdio helper
+      final channel = _channelFactory();
+
+      // Create and start the MCP server
+      final server = _serverFactory(
+        channel: channel,
+        logger: _logger,
+      );
+
+      _logger
+        ..info('MCP Server started successfully')
+        ..info('Available tools:')
+        ..info('''
+  - create: Create a very good Dart or Flutter project in seconds based on the provided template. Each template has a corresponding sub-command.''')
+        ..info('  - test: Run tests in a Dart or Flutter project.')
+        ..info(
+          '''
+           - packages_get: Install or update Dart/Flutter package dependencies.
+          Use after creating a project or modifying pubspec.yaml.
+          Supports recursive installation and package exclusion.''',
+        )
+        ..info(
+          '''
+  - packages_check_licenses: Verify package licenses for compliance and validation in a Dart or Flutter project.
+            Identifies license types (MIT, BSD, Apache, etc.) for all 
+            dependencies. Use to ensure license compatibility.''',
+        );
+
+      // Wait for the server to complete
+      // (this will block until the connection is closed)
+      await server.done;
+
+      return ExitCode.success.code;
+    } on Exception catch (e, stackTrace) {
+      _logger
+        ..err('Failed to start MCP server: $e')
+        ..err('Stack trace: $stackTrace');
+      return ExitCode.software.code;
+    }
+  }
+}