Offer GMCP/MSDP during connection and guard tick sends

The server never proactively offered GMCP or MSDP to clients, so
telnetlib3 logged "cannot send MSDP without negotiation" every second.
Now the server sends WILL GMCP and WILL MSDP on connection, and
send_msdp_vitals checks negotiation state before attempting to send.

src/mudlib/gmcp.py

@@ -13,6 +13,8 @@ log = logging.getLogger(__name__)
 
 def send_char_vitals(player: Player) -> None:
     """Send Char.Vitals — pl, max_pl, stamina, max_stamina."""
+    if not player.gmcp_enabled:
+        return
     player.send_gmcp(
         "Char.Vitals",
         {
@@ -26,6 +28,8 @@ def send_char_vitals(player: Player) -> None:
 
 def send_char_status(player: Player) -> None:
     """Send Char.Status — flying, resting, mode, in_combat."""
+    if not player.gmcp_enabled:
+        return
     player.send_gmcp(
         "Char.Status",
         {
@@ -39,6 +43,8 @@ def send_char_status(player: Player) -> None:
 
 def send_room_info(player: Player) -> None:
     """Send Room.Info — zone, coordinates, terrain, exits."""
+    if not player.gmcp_enabled:
+        return
     from mudlib.zone import Zone
 
     zone = player.location
@@ -78,6 +84,8 @@ def send_room_info(player: Player) -> None:
 
 def send_map_data(player: Player) -> None:
     """Send Room.Map — terrain viewport around player for client rendering."""
+    if not player.gmcp_enabled:
+        return
     from mudlib.zone import Zone
 
     zone = player.location
@@ -108,6 +116,8 @@ def send_map_data(player: Player) -> None:
 
 def send_msdp_vitals(player: Player) -> None:
     """Send MSDP variable updates for real-time gauges."""
+    if not player.msdp_enabled:
+        return
     player.send_msdp(
         {
             "HEALTH": str(round(player.pl, 1)),

src/mudlib/player.py

@@ -5,6 +5,8 @@ from __future__ import annotations
 from dataclasses import dataclass, field
 from typing import TYPE_CHECKING, Any
 
+from telnetlib3 import GMCP, MSDP
+
 from mudlib.caps import ClientCaps
 from mudlib.entity import Entity
 
@@ -54,6 +56,26 @@ class Player(Entity):
         if self.writer is not None:
             self.writer.send_msdp(variables)
 
+    @property
+    def gmcp_enabled(self) -> bool:
+        """Whether this client has GMCP negotiated."""
+        if self.writer is None:
+            return False
+        return bool(
+            self.writer.local_option.enabled(GMCP)
+            or self.writer.remote_option.enabled(GMCP)
+        )
+
+    @property
+    def msdp_enabled(self) -> bool:
+        """Whether this client has MSDP negotiated."""
+        if self.writer is None:
+            return False
+        return bool(
+            self.writer.local_option.enabled(MSDP)
+            or self.writer.remote_option.enabled(MSDP)
+        )
+
 
 # Global registry of connected players
 players: dict[str, Player] = {}

src/mudlib/server.py

@@ -9,6 +9,8 @@ import tomllib
 from typing import cast
 
 import telnetlib3
+from telnetlib3 import GMCP, MSDP, WILL
+from telnetlib3.server import TelnetServer
 from telnetlib3.server_shell import readline2
 
 import mudlib.combat.commands
@@ -224,6 +226,17 @@ async def handle_login(
             return {"success": False, "player_data": None}
 
 
+class MudTelnetServer(TelnetServer):
+    """Telnet server that offers GMCP and MSDP during negotiation."""
+
+    def begin_advanced_negotiation(self) -> None:
+        """Offer GMCP and MSDP alongside the standard options."""
+        super().begin_advanced_negotiation()
+        assert self.writer is not None
+        self.writer.iac(WILL, GMCP)
+        self.writer.iac(WILL, MSDP)
+
+
 async def shell(
     reader: telnetlib3.TelnetReader | telnetlib3.TelnetReaderUnicode,
     writer: telnetlib3.TelnetWriter | telnetlib3.TelnetWriterUnicode,
@@ -527,7 +540,11 @@ async def run_server() -> None:
     # MUD clients like tintin++ reject CHARSET immediately via MTTS, but
     # telnetlib3 still waits for the full timeout. 0.5s is plenty.
     server = await telnetlib3.create_server(
-        host=HOST, port=PORT, shell=shell, connect_maxwait=0.5
+        host=HOST,
+        port=PORT,
+        shell=shell,
+        connect_maxwait=0.5,
+        protocol_factory=MudTelnetServer,
     )
     log.info("listening on %s:%d", HOST, PORT)
 

tests/test_embedded_if.py

@@ -17,6 +17,15 @@ requires_zork = pytest.mark.skipif(not ZORK_PATH.exists(), reason="zork1.z3 not
 
 @dataclass
 class MockWriter:
+    def __post_init__(self):
+        # Mock option negotiation state
+        from unittest.mock import MagicMock
+
+        self.local_option = MagicMock()
+        self.local_option.enabled = MagicMock(return_value=False)
+        self.remote_option = MagicMock()
+        self.remote_option.enabled = MagicMock(return_value=False)
+
     def write(self, data):
         pass
 

tests/test_gmcp.py

@@ -47,6 +47,11 @@ def mock_writer():
     writer.drain = AsyncMock()
     writer.send_gmcp = MagicMock()
     writer.send_msdp = MagicMock()
+    # Option negotiation state (for gmcp_enabled/msdp_enabled checks)
+    writer.local_option = MagicMock()
+    writer.local_option.enabled = MagicMock(return_value=True)
+    writer.remote_option = MagicMock()
+    writer.remote_option.enabled = MagicMock(return_value=True)
     return writer
 
 
@@ -502,3 +507,58 @@ async def test_char_status_sent_on_rest_complete(player):
     ]
     assert len(status_calls) == 1
     assert status_calls[0][0][1]["resting"] is False
+
+
+def test_msdp_vitals_skipped_when_not_negotiated(player):
+    """Test send_msdp_vitals skips when MSDP is not negotiated."""
+    player.writer.local_option.enabled.return_value = False
+    player.writer.remote_option.enabled.return_value = False
+
+    send_msdp_vitals(player)
+
+    player.writer.send_msdp.assert_not_called()
+
+
+def test_msdp_enabled_property(player):
+    """Test msdp_enabled reflects negotiation state."""
+    player.writer.local_option.enabled.return_value = False
+    player.writer.remote_option.enabled.return_value = False
+    assert not player.msdp_enabled
+
+    player.writer.local_option.enabled.return_value = True
+    assert player.msdp_enabled
+
+
+def test_gmcp_enabled_property(player):
+    """Test gmcp_enabled reflects negotiation state."""
+    player.writer.local_option.enabled.return_value = False
+    player.writer.remote_option.enabled.return_value = False
+    assert not player.gmcp_enabled
+
+    player.writer.remote_option.enabled.return_value = True
+    assert player.gmcp_enabled
+
+
+def test_msdp_enabled_no_writer():
+    """Test msdp_enabled with no writer returns False."""
+    p = Player(name="NoWriter", writer=None)
+    assert not p.msdp_enabled
+
+
+def test_gmcp_enabled_no_writer():
+    """Test gmcp_enabled with no writer returns False."""
+    p = Player(name="NoWriter", writer=None)
+    assert not p.gmcp_enabled
+
+
+def test_gmcp_sends_skipped_when_not_negotiated(player):
+    """Test all GMCP send functions skip when GMCP is not negotiated."""
+    player.writer.local_option.enabled.return_value = False
+    player.writer.remote_option.enabled.return_value = False
+
+    send_char_vitals(player)
+    send_char_status(player)
+    send_room_info(player)
+    send_map_data(player)
+
+    player.writer.send_gmcp.assert_not_called()

tests/test_paint_mode.py

@@ -35,6 +35,13 @@ class MockWriter:
 
     def __init__(self):
         self.messages = []
+        # Mock option negotiation state
+        from unittest.mock import MagicMock
+
+        self.local_option = MagicMock()
+        self.local_option.enabled = MagicMock(return_value=False)
+        self.remote_option = MagicMock()
+        self.remote_option.enabled = MagicMock(return_value=False)
 
     def write(self, message: str):
         self.messages.append(message)