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

@@ -108,6 +108,8 @@ 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 +9,7 @@ import tomllib
 from typing import cast
 
 import telnetlib3
+from telnetlib3 import GMCP, MSDP, WILL
 from telnetlib3.server_shell import readline2
 
 import mudlib.combat.commands
@@ -238,6 +239,10 @@ async def shell(
 
     log.debug("new connection from %s", _writer.get_extra_info("peername"))
 
+    # Offer GMCP and MSDP so clients can negotiate
+    _writer.iac(WILL, GMCP)
+    _writer.iac(WILL, MSDP)
+
     _writer.write("Welcome to the MUD!\r\n")
     _writer.write("What is your name? ")
     await _writer.drain()

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 +507,45 @@ 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

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)