diff --git a/crdt-sync/crdt_sync/tests/test_tool_seeded_apps_todo_mcp.py b/crdt-sync/crdt_sync/tests/test_tool_seeded_apps_todo_mcp.py
new file mode 100644
index 0000000..45106da
--- /dev/null
+++ b/crdt-sync/crdt_sync/tests/test_tool_seeded_apps_todo_mcp.py
@@ -0,0 +1,38 @@
+# Copyright (c) 2026 Krzysztof Rudnicki
+"""The todo MCP server's desktop session is seeded by ``seed_session``.
+
+Split from :mod:`test_tool_seed_session_main` for the 250-line cap.
+"""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime
+import json
+from pathlib import Path
+from unittest.mock import patch
+
+from crdt_sync._config import credential_store_for
+from crdt_sync._credentials import FirebaseCredentials
+from tool import seed_session as ss
+
+_APP = "todo-mcp"
+
+
+def test_todo_mcp_is_a_default_app() -> None:
+    """``~/src/todo/mcp`` reads ``~/.config/todo-mcp/firebase_auth.json`` once
+    at start; ``--app todo-mcp`` is rejected by argparse unless it is listed."""
+    assert _APP in ss.DEFAULT_APPS
+
+
+def test_the_seed_lands_where_the_todo_mcp_server_reads_it(tmp_path: Path) -> None:
+    """The Dart server's ``seedCredentials`` path, in the usual shape."""
+    with patch.object(Path, "home", return_value=tmp_path):
+        credential_store_for(_APP).save(
+            FirebaseCredentials("fake-id", "fake-refresh", datetime.now(UTC))
+        )
+    written = tmp_path / ".config" / _APP / "firebase_auth.json"
+    assert set(json.loads(written.read_text())) == {
+        "id_token",
+        "refresh_token",
+        "expires_at",
+    }
diff --git a/crdt-sync/tool/_seeded_apps.py b/crdt-sync/tool/_seeded_apps.py
index 4ec499c..e47e2bf 100644
--- a/crdt-sync/tool/_seeded_apps.py
+++ b/crdt-sync/tool/_seeded_apps.py
@@ -67,4 +67,8 @@ DEFAULT_APPS: Final = (
     # /kartka/source_health via credential_store_for("kartka-source-eval")
     # and falls back to the retired password only with no session here.
     "kartka-source-eval",
+    # ~/src/todo/mcp: the Dart todo MCP server (systemd --user, :8735) is one
+    # more sync node with its own session, read once from
+    # ~/.config/todo-mcp/firebase_auth.json at start.
+    "todo-mcp",
 )