From 71d5fc0f7574f1e234ecf77c7ae65918639eccf8 Mon Sep 17 00:00:00 2001
From: Chris Hendrickson <chris@artificery.dev>
Date: Thu, 23 Apr 2026 16:13:53 -0400
Subject: [PATCH] Add MCP debug client and VS Code MCP config
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- tools/mcp_client.dart: spawns the compiled dew binary, connects via
  stdioChannel, initializes the MCP handshake, lists all tools, and calls
  kanban_list_tickets — useful for verifying the server without a real client
- .vscode/mcp.json: proper VS Code MCP server config using ${workspaceFolder}
  to point at the compiled binary with 'mcp serve' args

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .vscode/mcp.json      |   9 +++
 tools/mcp_client.dart | 132 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 141 insertions(+)
 create mode 100644 .vscode/mcp.json
 create mode 100644 tools/mcp_client.dart

diff --git a/.vscode/mcp.json b/.vscode/mcp.json
new file mode 100644
index 0000000..abc173d
--- /dev/null
+++ b/.vscode/mcp.json
@@ -0,0 +1,9 @@
+{
+  "servers": {
+    "dew": {
+      "type": "stdio",
+      "command": "${workspaceFolder}/.project/toolchain/bin/dew",
+      "args": ["mcp", "serve"]
+    }
+  }
+}
diff --git a/tools/mcp_client.dart b/tools/mcp_client.dart
new file mode 100644
index 0000000..df44cf3
--- /dev/null
+++ b/tools/mcp_client.dart
@@ -0,0 +1,132 @@
+/// Manual MCP client for debugging the Dew MCP server.
+///
+/// Usage:
+///   dart run tools/mcp_client.dart [path/to/dew/binary]
+///
+/// Defaults to .project/toolchain/bin/dew if no path is given.
+library;
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:dart_mcp/client.dart';
+import 'package:dart_mcp/stdio.dart';
+
+void main(List<String> args) async {
+  final binaryPath = args.isNotEmpty
+      ? args.first
+      : '.project/toolchain/bin/dew';
+
+  print('=== Dew MCP Debug Client ===');
+  print('Binary: $binaryPath');
+  print('');
+
+  // Log all raw JSON-RPC traffic.
+  final protocolLog = StreamController<String>();
+  protocolLog.stream.listen((msg) => stderr.writeln('[proto] $msg'));
+
+  // Start the server process.
+  print('Starting server process...');
+  final process = await Process.start(
+    binaryPath,
+    ['mcp', 'serve'],
+    // Forward server stderr to our stderr so startup messages are visible.
+  );
+
+  // Print server stderr in real time.
+  process.stderr
+      .transform(SystemEncoding().decoder)
+      .listen((line) => stderr.write('[server] $line'));
+
+  unawaited(
+    process.exitCode.then((code) {
+      if (code != 0) {
+        stderr.writeln('[client] Server process exited with code $code');
+      }
+    }),
+  );
+
+  final client = MCPClient(
+    Implementation(name: 'dew-debug-client', version: '0.1.0'),
+  );
+
+  final connection = client.connectServer(
+    stdioChannel(input: process.stdout, output: process.stdin),
+    protocolLogSink: protocolLog.sink,
+  );
+
+  unawaited(connection.done.then((_) {
+    stderr.writeln('[client] Connection closed.');
+    process.kill();
+  }));
+
+  // --- Initialise ---
+  print('Sending initialize...');
+  late InitializeResult initResult;
+  try {
+    initResult = await connection.initialize(
+      InitializeRequest(
+        protocolVersion: ProtocolVersion.latestSupported,
+        capabilities: client.capabilities,
+        clientInfo: client.implementation,
+      ),
+    ).timeout(const Duration(seconds: 5));
+  } on TimeoutException {
+    stderr.writeln('[client] Timed out waiting for initialize response.');
+    process.kill();
+    exit(1);
+  } catch (e) {
+    stderr.writeln('[client] Initialize failed: $e');
+    process.kill();
+    exit(1);
+  }
+
+  print('Server: ${initResult.serverInfo?.name} ${initResult.serverInfo?.version}');
+  print('Protocol: ${initResult.protocolVersion}');
+  print('');
+
+  if (initResult.capabilities.tools == null) {
+    stderr.writeln('[client] Server does not advertise tools capability.');
+    await client.shutdown();
+    process.kill();
+    exit(1);
+  }
+
+  connection.notifyInitialized();
+
+  // --- List tools ---
+  print('Listing tools...');
+  final toolsResult = await connection.listTools(ListToolsRequest());
+  if (toolsResult.tools.isEmpty) {
+    print('  (no tools registered)');
+  } else {
+    for (final tool in toolsResult.tools) {
+      print('  • ${tool.name}: ${tool.description ?? "(no description)"}');
+    }
+  }
+
+  print('');
+
+  // --- Call kanban_list_tickets ---
+  print('Calling kanban_list_tickets...');
+  try {
+    final result = await connection.callTool(
+      CallToolRequest(name: 'kanban_list_tickets', arguments: {}),
+    );
+    if (result.isError == true) {
+      print('  Error: ${result.content.map((c) => (c as TextContent).text).join()}');
+    } else {
+      print('  Result:');
+      for (final c in result.content) {
+        print('    ${(c as TextContent).text}');
+      }
+    }
+  } catch (e) {
+    print('  Failed: $e');
+  }
+
+  print('');
+  print('Done. Shutting down.');
+  await client.shutdown();
+  process.kill();
+}