Implement MCP tool registry and kanban tool provider

- Add McpTool + McpToolProvider interface to core
- Add McpToolRegistry to mcp package (aggregates providers)
- Add DewMcpServer (MCPServer + ToolsSupport via dart_mcp 0.5.0)
- Add 'mcp serve' subcommand — starts a real stdio MCP server
- Implement KanbanToolProvider with 5 tools:
  kanban_create_ticket, kanban_list_tickets, kanban_get_ticket,
  kanban_update_ticket, kanban_delete_ticket
- Wire McpToolRegistry + KanbanToolProvider in CLI
- 26 tests passing, dart analyze clean

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

packages/cli/bin/dew.dart

@@ -4,16 +4,17 @@ import 'package:dew_kanban/dew_kanban.dart' as kanban;
 import 'package:dew_mcp/dew_mcp.dart' as mcp;
 
 Future<void> main(List<String> args) async {
-  final registry = CommandRegistry();
-  kanban.registerCommands(registry);
-  mcp.registerCommands(registry);
+  final commandRegistry = CommandRegistry();
+  final toolRegistry = mcp.McpToolRegistry();
 
-  final runner = CommandRunner<void>(
-    'dew',
-    'A project management tool.',
-  );
+  toolRegistry.register(kanban.KanbanToolProvider());
 
-  for (final command in registry.commands) {
+  kanban.registerCommands(commandRegistry);
+  mcp.registerCommands(commandRegistry, toolRegistry);
+
+  final runner = CommandRunner<void>('dew', 'A project management tool.');
+
+  for (final command in commandRegistry.commands) {
     runner.addCommand(command);
   }
 

packages/core/lib/dew_core.dart

@@ -2,3 +2,4 @@ library;
 
 export 'src/config.dart';
 export 'src/dew_core_base.dart';
+export 'src/mcp_tool_provider.dart';

packages/core/lib/src/mcp_tool_provider.dart

@@ -0,0 +1,27 @@
+typedef McpToolHandler = Future<String> Function(Map<String, dynamic> args);
+
+/// A single tool exposed to an MCP client.
+class McpTool {
+  final String name;
+  final String description;
+
+  /// Raw JSON Schema object (type: object) describing the tool's parameters.
+  final Map<String, dynamic> inputSchema;
+
+  final McpToolHandler handler;
+
+  const McpTool({
+    required this.name,
+    required this.description,
+    required this.inputSchema,
+    required this.handler,
+  });
+}
+
+/// Implement this interface to expose tools to the MCP server.
+///
+/// Feature packages implement this in their own library without needing to
+/// depend on [packages/mcp] — they only depend on [packages/core].
+abstract interface class McpToolProvider {
+  List<McpTool> get tools;
+}

packages/kanban/lib/dew_kanban.dart

@@ -1,6 +1,7 @@
 library;
 
 export 'src/dew_kanban_base.dart';
+export 'src/kanban_tool_provider.dart';
 export 'src/ticket.dart';
 export 'src/ticket_store.dart';
 

packages/kanban/lib/src/kanban_tool_provider.dart

@@ -0,0 +1,204 @@
+import 'package:dew_core/dew_core.dart';
+import 'package:path/path.dart' as p;
+
+import 'ticket.dart';
+import 'ticket_store.dart';
+
+/// Exposes Kanban board operations as MCP tools.
+class KanbanToolProvider implements McpToolProvider {
+  @override
+  List<McpTool> get tools => [
+    McpTool(
+      name: 'kanban_create_ticket',
+      description: 'Create a new kanban ticket.',
+      inputSchema: {
+        'type': 'object',
+        'properties': {
+          'title': {'type': 'string', 'description': 'Ticket title.'},
+          'type': {
+            'type': 'string',
+            'description': 'Ticket type (e.g. task, bug).',
+          },
+          'column': {
+            'type': 'string',
+            'description':
+                'Initial column. Defaults to the first configured column.',
+          },
+          'body': {'type': 'string', 'description': 'Ticket description.'},
+        },
+        'required': ['title', 'type'],
+      },
+      handler: _createTicket,
+    ),
+    McpTool(
+      name: 'kanban_list_tickets',
+      description: 'List kanban tickets, optionally filtered by column or type.',
+      inputSchema: {
+        'type': 'object',
+        'properties': {
+          'column': {
+            'type': 'string',
+            'description': 'Filter to tickets in this column.',
+          },
+          'type': {
+            'type': 'string',
+            'description': 'Filter to tickets of this type.',
+          },
+        },
+      },
+      handler: _listTickets,
+    ),
+    McpTool(
+      name: 'kanban_get_ticket',
+      description: 'Get a kanban ticket by ID.',
+      inputSchema: {
+        'type': 'object',
+        'properties': {
+          'id': {
+            'type': 'string',
+            'description': 'Ticket ID (e.g. DEW-0001).',
+          },
+        },
+        'required': ['id'],
+      },
+      handler: _getTicket,
+    ),
+    McpTool(
+      name: 'kanban_update_ticket',
+      description: 'Update one or more fields on an existing kanban ticket.',
+      inputSchema: {
+        'type': 'object',
+        'properties': {
+          'id': {'type': 'string', 'description': 'Ticket ID.'},
+          'title': {'type': 'string', 'description': 'New title.'},
+          'type': {'type': 'string', 'description': 'New ticket type.'},
+          'column': {'type': 'string', 'description': 'New column.'},
+          'body': {
+            'type': 'string',
+            'description': 'New body (replaces existing body).',
+          },
+        },
+        'required': ['id'],
+      },
+      handler: _updateTicket,
+    ),
+    McpTool(
+      name: 'kanban_delete_ticket',
+      description: 'Delete a kanban ticket by ID.',
+      inputSchema: {
+        'type': 'object',
+        'properties': {
+          'id': {'type': 'string', 'description': 'Ticket ID.'},
+        },
+        'required': ['id'],
+      },
+      handler: _deleteTicket,
+    ),
+  ];
+
+  Future<TicketStore> _store() async {
+    final context = await ProjectContext.find();
+    return TicketStore(
+      kanbanDir: p.join(context.root, '.project', 'kanban'),
+      prefix: context.config.kanban.prefix,
+    );
+  }
+
+  Future<String> _createTicket(Map<String, dynamic> args) async {
+    final context = await ProjectContext.find();
+    final config = context.config.kanban;
+    final title = args['title'] as String;
+    final typeId = args['type'] as String;
+    final column = args['column'] as String? ?? config.columns.first.id;
+    final body = args['body'] as String? ?? '';
+
+    if (!config.ticketTypes.any((t) => t.id == typeId)) {
+      throw ArgumentError(
+        'Unknown type "$typeId". Valid: ${config.ticketTypes.map((t) => t.id).join(', ')}',
+      );
+    }
+    if (!config.columns.any((c) => c.id == column)) {
+      throw ArgumentError(
+        'Unknown column "$column". Valid: ${config.columns.map((c) => c.id).join(', ')}',
+      );
+    }
+
+    final store = TicketStore(
+      kanbanDir: p.join(context.root, '.project', 'kanban'),
+      prefix: config.prefix,
+    );
+    final ticket = await store.create(
+      title: title,
+      type: typeId,
+      column: column,
+      body: body,
+    );
+    return 'Created ${ticket.id}: ${ticket.title}';
+  }
+
+  Future<String> _listTickets(Map<String, dynamic> args) async {
+    final columnFilter = args['column'] as String?;
+    final typeFilter = args['type'] as String?;
+    final store = await _store();
+    var tickets = await store.list();
+
+    if (columnFilter != null) {
+      tickets = tickets.where((t) => t.column == columnFilter).toList();
+    }
+    if (typeFilter != null) {
+      tickets = tickets.where((t) => t.type == typeFilter).toList();
+    }
+
+    if (tickets.isEmpty) return 'No tickets found.';
+
+    return tickets
+        .map((t) => '[${t.id}] (${t.type}) [${t.column}] ${t.title}')
+        .join('\n');
+  }
+
+  Future<String> _getTicket(Map<String, dynamic> args) async {
+    final id = (args['id'] as String).toUpperCase();
+    final store = await _store();
+    final ticket = await store.findById(id);
+    if (ticket == null) throw ArgumentError('Ticket $id not found.');
+    return _formatTicket(ticket);
+  }
+
+  Future<String> _updateTicket(Map<String, dynamic> args) async {
+    final id = (args['id'] as String).toUpperCase();
+    final store = await _store();
+    final updated = await store.update(
+      id,
+      title: args['title'] as String?,
+      type: args['type'] as String?,
+      column: args['column'] as String?,
+      body: args['body'] as String?,
+    );
+    return 'Updated ${updated.id}.\n${_formatTicket(updated)}';
+  }
+
+  Future<String> _deleteTicket(Map<String, dynamic> args) async {
+    final id = (args['id'] as String).toUpperCase();
+    final store = await _store();
+    await store.delete(id);
+    return 'Deleted $id.';
+  }
+
+  String _formatTicket(Ticket t) {
+    final buf = StringBuffer();
+    buf.writeln('[${t.id}] (${t.type}) [${t.column}] ${t.title}');
+    buf.writeln(
+      'Created: ${t.created.toLocal().toString().split('.').first}',
+    );
+    if (t.body.isNotEmpty) {
+      buf.writeln();
+      buf.writeln(t.body);
+    }
+    for (final (i, comment) in t.comments.indexed) {
+      buf.writeln();
+      buf.writeln('── Comment ${i + 1} ${'─' * 20}');
+      buf.write(comment);
+    }
+    return buf.toString().trimRight();
+  }
+}

packages/kanban/test/dew_kanban_test.dart

@@ -139,5 +139,73 @@ void main() {
       );
     });
   });
+
+  group('KanbanToolProvider', () {
+    test('exposes five tools with unique names', () {
+      final provider = KanbanToolProvider();
+      expect(provider.tools, hasLength(5));
+      final names = provider.tools.map((t) => t.name).toSet();
+      expect(names, {
+        'kanban_create_ticket',
+        'kanban_list_tickets',
+        'kanban_get_ticket',
+        'kanban_update_ticket',
+        'kanban_delete_ticket',
+      });
+    });
+
+    test('all tools have non-empty descriptions and object inputSchema', () {
+      for (final tool in KanbanToolProvider().tools) {
+        expect(tool.description, isNotEmpty, reason: '${tool.name} description');
+        expect(tool.inputSchema['type'], 'object',
+            reason: '${tool.name} schema type');
+      }
+    });
+
+    test('create and list tools have handlers that work', () async {
+      // Use a real temp dir with a fake dew.yaml so ProjectContext.find()
+      // resolves — handlers call ProjectContext.find() internally.
+      final tempDir = await Directory.systemTemp.createTemp('kanban_tool_test_');
+      final origDir = Directory.current;
+      try {
+        await Directory(p.join(tempDir.path, '.project', 'kanban')).create(recursive: true);
+        await File(p.join(tempDir.path, '.project', 'dew.yaml')).writeAsString('''
+dew:
+  mcp:
+    host: localhost
+    port: 9090
+  kanban:
+    prefix: T
+    ticket_types:
+      - id: task
+        name: Task
+    columns:
+      - id: todo
+        name: To Do
+        color: blue
+''');
+        Directory.current = tempDir;
+        final provider = KanbanToolProvider();
+
+        final createTool = provider.tools.firstWhere(
+          (t) => t.name == 'kanban_create_ticket',
+        );
+        final result = await createTool.handler({
+          'title': 'Hello',
+          'type': 'task',
+        });
+        expect(result, contains('T-0001'));
+
+        final listTool = provider.tools.firstWhere(
+          (t) => t.name == 'kanban_list_tickets',
+        );
+        final listResult = await listTool.handler({});
+        expect(listResult, contains('T-0001'));
+      } finally {
+        Directory.current = origDir;
+        await tempDir.delete(recursive: true);
+      }
+    });
+  });
 }
 

packages/mcp/lib/dew_mcp.dart

@@ -1,13 +1,19 @@
 library;
 
 export 'src/dew_mcp_base.dart';
+export 'src/mcp_tool_registry.dart';
 
 import 'package:dew_core/dew_core.dart';
 import 'package:dew_mcp/src/dew_mcp_base.dart';
+import 'package:dew_mcp/src/mcp_tool_registry.dart';
 
-/// Registers all MCP commands into [registry].
-void registerCommands(CommandRegistry registry) {
-  registry.register(McpCommand());
+/// Registers the MCP command into [commandRegistry].
+///
+/// [toolRegistry] is passed to [McpCommand] so the `serve` subcommand can
+/// start the server with all registered tool providers.
+void registerCommands(
+  CommandRegistry commandRegistry,
+  McpToolRegistry toolRegistry,
+) {
+  commandRegistry.register(McpCommand(toolRegistry));
 }
-
-// TODO: Export any libraries intended for clients of this package.

packages/mcp/lib/src/commands/serve_command.dart

@@ -0,0 +1,41 @@
+import 'dart:io' as io;
+
+import 'package:dart_mcp/stdio.dart';
+import 'package:dew_core/dew_core.dart';
+
+import '../dew_mcp_server.dart';
+import '../mcp_tool_registry.dart';
+
+class ServeCommand extends DewCommand {
+  final McpToolRegistry _toolRegistry;
+
+  ServeCommand(this._toolRegistry);
+
+  @override
+  final String name = 'serve';
+
+  @override
+  final String description =
+      'Start the Dew MCP server on stdio. '
+      'Connect your MCP client to this process.';
+
+  @override
+  Future<void> run() async {
+    final context = await ProjectContext.find();
+    final tools = _toolRegistry.allTools;
+
+    io.stderr.writeln(
+      'Dew MCP server starting — '
+      '${tools.length} tool(s) registered, '
+      'project root: ${context.root}',
+    );
+
+    DewMcpServer(
+      stdioChannel(input: io.stdin, output: io.stdout),
+      tools,
+    );
+
+    // Keep the process alive until the MCP client closes the connection.
+    await io.stdin.drain<void>();
+  }
+}

packages/mcp/lib/src/dew_mcp_base.dart

@@ -1,7 +1,14 @@
 import 'package:dew_core/dew_core.dart';
 
+import 'commands/serve_command.dart';
+import 'mcp_tool_registry.dart';
+
 /// Top-level CLI command for MCP server operations.
 class McpCommand extends DewCommand {
+  McpCommand(McpToolRegistry toolRegistry) {
+    addSubcommand(ServeCommand(toolRegistry));
+  }
+
   @override
   final String name = 'mcp';
 

packages/mcp/lib/src/dew_mcp_server.dart

@@ -0,0 +1,40 @@
+import 'package:dart_mcp/server.dart';
+import 'package:dew_core/dew_core.dart';
+
+/// An MCP server that serves all tools registered in a [McpToolRegistry].
+base class DewMcpServer extends MCPServer with ToolsSupport {
+  DewMcpServer(super.channel, List<McpTool> tools)
+    : super.fromStreamChannel(
+        implementation: Implementation(name: 'dew', version: '1.0.0'),
+        instructions:
+            'Tools for managing a Dew project (kanban tickets, etc.).',
+      ) {
+    for (final tool in tools) {
+      registerTool(
+        Tool(
+          name: tool.name,
+          description: tool.description,
+          // ObjectSchema is an extension type over Map<String,Object?>;
+          // pass validateArguments:false to avoid runtime cast issues with
+          // nested Map<String,dynamic> literals.
+          inputSchema: ObjectSchema.fromMap(
+            tool.inputSchema.cast<String, Object?>(),
+          ),
+        ),
+        (request) async {
+          final args = (request.arguments ?? const {}).cast<String, dynamic>();
+          try {
+            final text = await tool.handler(args);
+            return CallToolResult(content: [Content.text(text: text)]);
+          } catch (e) {
+            return CallToolResult(
+              content: [Content.text(text: 'Error: $e')],
+              isError: true,
+            );
+          }
+        },
+        validateArguments: false,
+      );
+    }
+  }
+}

packages/mcp/lib/src/mcp_tool_registry.dart

@@ -0,0 +1,13 @@
+import 'package:dew_core/dew_core.dart';
+
+/// Collects [McpToolProvider] instances and exposes their combined tool list.
+class McpToolRegistry {
+  final List<McpToolProvider> _providers = [];
+
+  /// Adds [provider] to the registry.
+  void register(McpToolProvider provider) => _providers.add(provider);
+
+  /// All tools from every registered provider, in registration order.
+  List<McpTool> get allTools =>
+      List.unmodifiable(_providers.expand((p) => p.tools));
+}

packages/mcp/pubspec.yaml

@@ -12,6 +12,7 @@ environment:
 dependencies:
   dew_core:
     path: ../core
+  dart_mcp: ^0.5.0
 
 dev_dependencies:
   lints: ^6.0.0

packages/mcp/test/mcp_test.dart

@@ -1,19 +1,57 @@
-import 'package:dew_mcp/dew_mcp.dart';
 import 'package:dew_core/dew_core.dart';
+import 'package:dew_mcp/dew_mcp.dart';
 import 'package:test/test.dart';
 
+class _PingProvider implements McpToolProvider {
+  @override
+  List<McpTool> get tools => [
+    McpTool(
+      name: 'ping',
+      description: 'Returns pong.',
+      inputSchema: {'type': 'object', 'properties': {}},
+      handler: (_) async => 'pong',
+    ),
+  ];
+}
+
 void main() {
   group('McpCommand', () {
     test('has correct name and description', () {
-      final cmd = McpCommand();
+      final cmd = McpCommand(McpToolRegistry());
       expect(cmd.name, 'mcp');
       expect(cmd.description, isNotEmpty);
     });
 
+    test('has serve subcommand', () {
+      final cmd = McpCommand(McpToolRegistry());
+      expect(cmd.subcommands.keys, contains('serve'));
+    });
+
     test('registerCommands adds mcp command to registry', () {
-      final registry = CommandRegistry();
-      registerCommands(registry);
-      expect(registry.commands.map((c) => c.name), contains('mcp'));
+      final commandRegistry = CommandRegistry();
+      registerCommands(commandRegistry, McpToolRegistry());
+      expect(commandRegistry.commands.map((c) => c.name), contains('mcp'));
+    });
+  });
+
+  group('McpToolRegistry', () {
+    test('starts empty', () {
+      expect(McpToolRegistry().allTools, isEmpty);
+    });
+
+    test('register adds provider tools', () {
+      final registry = McpToolRegistry();
+      registry.register(_PingProvider());
+      expect(registry.allTools, hasLength(1));
+      expect(registry.allTools.first.name, 'ping');
+    });
+
+    test('aggregates tools from multiple providers', () {
+      final registry = McpToolRegistry();
+      registry.register(_PingProvider());
+      registry.register(_PingProvider());
+      expect(registry.allTools, hasLength(2));
     });
   });
 }
+

pubspec.lock

@@ -129,6 +129,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.0.7"
+  dart_mcp:
+    dependency: transitive
+    description:
+      name: dart_mcp
+      sha256: "92a2ee1cca577ed54fa4f3d5ae0e80ce2dd61e1892e793bb4f951b30eab9c4b1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.5.0"
   file:
     dependency: transitive
     description:
@@ -201,6 +209,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.11.0"
+  json_rpc_2:
+    dependency: transitive
+    description:
+      name: json_rpc_2
+      sha256: "82dfd37d3b2e5030ae4729e1d7f5538cbc45eb1c73d618b9272931facac3bec1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.1.0"
   lints:
     dependency: "direct dev"
     description:
@@ -417,6 +433,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.4"
+  stream_transform:
+    dependency: transitive
+    description:
+      name: stream_transform
+      sha256: ad47125e588cfd37a9a7f86c7d6356dde8dfe89d071d293f80ca9e9273a33871
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.1"
   string_scanner:
     dependency: transitive
     description: