fix(network): prevent null multiplayer peer crashes offline/teardown and fix Nakama RPC session validation

addons/godot_ai/connection.gd

@@ -48,6 +48,12 @@ var server_version := ""
 
 var dispatcher
 var log_buffer
+var surfaced_error_tracker
+## Set by plugin.gd. Lets the per-frame play-state poll end game-run
+## bookkeeping when the game exits on its own (self-quit, crash) — the
+## debugger session's stopped signal is not reliably connected, and no MCP
+## stop op runs in that path (#642).
+var debugger_plugin
 ## Set by plugin.gd when the HTTP port is occupied by an incompatible or
 ## unverified server. Keeping the Connection node alive lets handlers and the
 ## dock share one object, but no WebSocket is opened to the wrong server.
@@ -89,6 +95,10 @@ func _process(delta: float) -> void:
 	if pause_processing:
 		return
 	_peer.poll()
+	## Run-stop bookkeeping must not wait behind the socket-state machine:
+	## if the game stops while disconnected, the first command drained on
+	## reconnect would still observe stale "live" state (PR #642 review).
+	_check_game_run_play_state(EditorInterface.is_playing_scene())
 
 	match _peer.get_ready_state():
 		WebSocketPeer.STATE_OPEN:
@@ -309,6 +319,8 @@ func send_deferred_response(request_id: String, payload: Dictionary) -> void:
 	## `readiness_after` payload field were ever dropped.
 	if not response.has("readiness"):
 		response["readiness"] = get_readiness()
+	if not response.has("error_watermark"):
+		_stamp_error_watermark(response)
 	if _send_json(response) and dispatcher != null:
 		dispatcher.complete_deferred_response(request_id)
 
@@ -319,10 +331,15 @@ func _hook_editor_signals() -> void:
 	EditorInterface.get_editor_settings()  # ensure interface is ready
 	_last_scene_path = _get_current_scene_path()
 	_last_play_state = EditorInterface.is_playing_scene()
+	_last_play_state_for_run = _last_play_state
 
 
 var _last_scene_path := ""
 var _last_play_state := false
+## Separate edge tracker for game-run bookkeeping: _last_play_state only
+## advances when the play_state_changed event sends successfully, but ending
+## run tracking must not depend on the websocket being up.
+var _last_play_state_for_run := false
 var _last_readiness := ""
 
 
@@ -359,7 +376,22 @@ func _check_state_changes() -> void:
 		if send_event("readiness_changed", {"readiness": readiness}):
 			_last_readiness = readiness
 			if log_buffer:
-				log_buffer.log("[event] readiness -> %s" % readiness)
+				## echo=false: readiness flips on every filesystem scan
+				## (each import cycles importing -> ready), so echoing to
+				## console spams every install during normal editing (#626).
+				## The line stays in the ring for the dock's log panel.
+				log_buffer.log("[event] readiness -> %s" % readiness, false)
+
+
+## Playing→stopped edge for game-run bookkeeping. Runs every process tick
+## (any socket state) so a self-quit game's run ends even while the
+## transport is down or reconnecting.
+func _check_game_run_play_state(playing: bool) -> void:
+	if playing == _last_play_state_for_run:
+		return
+	if not playing and debugger_plugin != null:
+		debugger_plugin.note_editor_play_stopped()
+	_last_play_state_for_run = playing
 
 
 func _get_current_scene_path() -> String:
@@ -403,6 +435,7 @@ func _handle_outbound_backpressure(
 		return false
 
 	var err_response := _make_backpressure_error(request_id, buffered_bytes, message_bytes)
+	_stamp_error_watermark(err_response)
 	var err_text := JSON.stringify(err_response)
 	var err_bytes := err_text.to_utf8_buffer().size()
 	if _would_exceed_outbound_backpressure(buffered_bytes, err_bytes):
@@ -457,6 +490,10 @@ static func _make_backpressure_error(
 	}
 
 
+func _stamp_error_watermark(response: Dictionary) -> void:
+	McpSurfacedErrorTracker.stamp_watermark(response, surfaced_error_tracker)
+
+
 ## Build a human-readable session ID of form "<slug>@<4hex>" from the project path.
 ## The slug is derived from the project directory name so agents can recognize
 ## which editor they're targeting; the hex suffix disambiguates same-project twins.