diff --git a/lib/mcp/task_service.dart b/lib/mcp/task_service.dart
index fe965ac..8f23e0f 100644
--- a/lib/mcp/task_service.dart
+++ b/lib/mcp/task_service.dart
@@ -17,7 +17,7 @@ class TaskService {
   final BoardClient? _board;
   Future<void> _tail = Future.value();
 
-  Future<String> _serial(Future<String> Function() body) {
+  Future<T> _serial<T>(Future<T> Function() body) {
     final run = _tail.then((_) => body());
     _tail = run.then((_) {}, onError: (_) {});
     return run;
@@ -44,8 +44,14 @@ class TaskService {
     }
   }
 
-  /// `add_task`: joins the repo's open note (by: claude), or creates it.
-  Future<String> add(Map<String, dynamic> args) => _serial(() async {
+  /// `add_task`: joins the repo's open note (by: claude), or creates it. A
+  /// board Start after a merge runs once the other calls may go again.
+  Future<String> add(Map<String, dynamic> args) async {
+    final (:reply, :start) = await _serial(() => _add(args));
+    return start == null ? reply : '$reply\n${await start()}';
+  }
+
+  Future<SplitReply> _add(Map<String, dynamic> args) async {
     final a = _Args(args);
     final repo = a.repo(required: true)!;
     final title = a.required('title');
@@ -71,8 +77,9 @@ class TaskService {
       priority: a.priority() ?? Priority.medium,
       by: 'claude',
     );
-    return await _save(added.note, added.appended ? 'appended to' : 'added');
-  });
+    final verb = added.appended ? 'appended to' : 'added';
+    return (reply: await _save(added.note, verb), start: null);
+  }
 
   /// `list_tasks`: repo tasks, open ones unless `status` says otherwise.
   Future<String> list(Map<String, dynamic> args) => _serial(() async {
diff --git a/lib/mcp/task_split.dart b/lib/mcp/task_split.dart
index 8b88b55..9cfef54 100644
--- a/lib/mcp/task_split.dart
+++ b/lib/mcp/task_split.dart
@@ -10,9 +10,14 @@ import 'package:todo/mcp/board_client.dart';
 /// Saves [note] and returns `<verb> <id>` plus its list line.
 typedef SaveNote = Future<String> Function(Note note, String verb);
 
-/// Adds a separate task, merging into a duplicate's note when it is idle,
-/// and clicks Start on the board after a merge that may run.
-Future<String> addSplit(
+/// A saved split add: its reply so far, and the board Start still to run.
+/// The caller runs [start] after releasing its lock, since the board learns
+/// about the merged section by calling this same server (T1865).
+typedef SplitReply = ({String reply, Future<String> Function()? start});
+
+/// Adds a separate task, merging into a duplicate's note when it is idle;
+/// a merge that may run comes back with the Start to click on the board.
+Future<SplitReply> addSplit(
   NoteRepository repository,
   BoardClient? board,
   SaveNote save, {
@@ -34,19 +39,28 @@ Future<String> addSplit(
   );
   if (added.kind != SplitKind.merged) {
     final reply = await save(added.note, 'added');
-    return added.why == null ? reply : '$reply\n${added.why}';
+    return (
+      reply: added.why == null ? reply : '$reply\n${added.why}',
+      start: null,
+    );
   }
   final reply = await save(added.note, 'merged into');
   final block = startBlock(doneCheck, body);
-  if (block != null) return '$reply\nstart: skipped ($block)';
-  final start = board == null
-      ? (ok: false, reason: 'no board configured', item: null)
-      : await board.start(
-          added.note.id,
-          title.trim(),
-          sections: sectionCount(added.note.text),
-        );
-  if (start.ok) return '$reply\nstart: ok ${start.item}';
-  return '$reply\nstart: {ok: false, reason: "${start.reason}"}; '
-      'the merge is saved, click Start on the board by hand';
+  if (block != null) {
+    return (reply: '$reply\nstart: skipped ($block)', start: null);
+  }
+  Future<String> start() async {
+    final s = board == null
+        ? (ok: false, reason: 'no board configured', item: null)
+        : await board.start(
+            added.note.id,
+            title.trim(),
+            sections: sectionCount(added.note.text),
+          );
+    if (s.ok) return 'start: ok ${s.item}';
+    return 'start: {ok: false, reason: "${s.reason}"}; '
+        'the merge is saved, click Start on the board by hand';
+  }
+
+  return (reply: reply, start: start);
 }
diff --git a/pubspec.yaml b/pubspec.yaml
index e24c481..60ceda1 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -16,7 +16,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 # In Windows, build-name is used as the major, minor, and patch parts
 # of the product and file versions while build-number is used as the build suffix.
-version: 1.0.63+1
+version: 1.0.64+1
 
 environment:
   sdk: ^3.12.2
diff --git a/test/mcp/mcp_board_refresh_test.dart b/test/mcp/mcp_board_refresh_test.dart
new file mode 100644
index 0000000..ac505b4
--- /dev/null
+++ b/test/mcp/mcp_board_refresh_test.dart
@@ -0,0 +1,108 @@
+// T1865: the real board learns about notes by calling this MCP server, so a
+// merged add_task must not hold the server while it waits for the board.
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
+import 'package:mcp_dart/mcp_dart.dart';
+import 'package:todo/mcp/board_client.dart';
+
+import 'mcp_harness.dart';
+
+void main() {
+  late McpHarness h;
+  late McpClient c;
+  late McpClient boardSide;
+  String? note;
+  var cards = <Map<String, dynamic>>[];
+  final posts = <String>[];
+
+  // A board whose every read refreshes its cards from this MCP server, as
+  // the real one does; a refresh that cannot get through keeps stale cards.
+  Future<List<Map<String, dynamic>>> refresh() async {
+    final id = note;
+    if (id == null) return cards;
+    try {
+      final text = await h
+          .call(boardSide, 'get_task', {'id': id})
+          .timeout(const Duration(milliseconds: 300));
+      final n = '\n$text'.split('\n## ').length - 1;
+      cards = [
+        for (var i = 0; i < n; i++)
+          {
+            'id': '${id.substring(0, 8)}-$i',
+            'title': 'Młody',
+            'column': 'backlog',
+            'actions': [
+              {'id': 'start', 'enabled': true},
+            ],
+          },
+      ];
+    } on TimeoutException {
+      // Stale, like the real cache when the server does not answer.
+    }
+    return cards;
+  }
+
+  final board = BoardClient(
+    wait: const Duration(seconds: 2),
+    poll: const Duration(milliseconds: 20),
+    client: MockClient((req) async {
+      if (req.method == 'POST') {
+        posts.add(req.url.path);
+        return http.Response('{"ok":true}', 200);
+      }
+      if (req.url.path == '/api/board') {
+        return http.Response.bytes(
+          utf8.encode(jsonEncode({'tasks': await refresh()})),
+          200,
+        );
+      }
+      return http.Response('<meta name="todoimpl-csrf" content="t">', 200);
+    }),
+  );
+
+  setUp(() async {
+    note = null;
+    cards = [];
+    posts.clear();
+    h = McpHarness(board: board);
+    await h.start();
+    c = await h.connect();
+    boardSide = await h.connect();
+  });
+  tearDown(() => h.dispose());
+
+  test('T1865: Start after a merge sees the board refreshed', () async {
+    final args = {
+      'repo': 'kuhyx/herosi',
+      'title': 'Młody',
+      'body': 'what',
+      'new_note': true,
+      'done_check': 'true',
+    };
+    note = idIn(await h.call(c, 'add_task', args));
+    final r = await h.call(c, 'add_task', args);
+    expect(r, startsWith('merged into $note'));
+    expect(r, contains('start: ok ${note!.substring(0, 8)}-1'));
+    expect(posts, ['/api/task/${note!.substring(0, 8)}-1/start']);
+  });
+
+  test('a merge with no board configured says click Start', () async {
+    final bare = McpHarness();
+    await bare.start();
+    addTearDown(bare.dispose);
+    final client = await bare.connect();
+    final args = {'repo': 'kuhyx/herosi', 'title': 'A', 'new_note': true};
+    final x = idIn(await bare.call(client, 'add_task', args));
+    final r = await bare.call(client, 'add_task', {
+      ...args,
+      'done_check': 'true',
+    });
+    expect(r, startsWith('merged into $x'));
+    expect(r, contains('reason: "no board configured"'));
+    expect(r, contains('click Start on the board by hand'));
+  });
+}