From d72fcc7847c90f11070c4c402e4903df027d5afb Mon Sep 17 00:00:00 2001
From: Jeroen Schweitzer <jpmschweitzer@gmail.com>
Date: Tue, 21 Apr 2026 17:29:49 +0200
Subject: [PATCH] =?UTF-8?q?fix(protocol):=20drop=20PROTOCOL=5FVERSION=20lo?=
 =?UTF-8?q?ckstep=20=E2=80=94=20D-192=20(#875)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Removes the version-mismatch guard from Protocol.decode_snapshot() and the
PROTOCOL_VERSION constant from the client (server side done in #874).

Core changes:
- protocol.gd: remove const PROTOCOL_VERSION, remove version mismatch guard,
  remove "version" from return dict, add gauntlet_mode/room_id decode
- sim_bridge.gd: remove handshake version check; relax handshake guard to
  require only a valid Dictionary (server no longer sends protocol_version);
  emit handshake_complete(0) for API compat
- loading_screen.gd: drop "· protocol N" suffix from version label
- test_harness.gd: replace Protocol.PROTOCOL_VERSION with literal 23

Test updates (21 files): replace "version": Protocol.PROTOCOL_VERSION with
"version": 23 in all snapshot bytes dicts; remove snapshot.version == N
assertions; remove version-rejection tests (test_rejects_version_6,
test_decode_snapshot_rejects_missing_version, test_decode_snapshot_rejects_old_version,
test_protocol_rejects_version_mismatch, test_sim_bridge_test_snapshot_uses_current_protocol_version).

Also includes: #872 bookmark_catalog carry-forward regression test, and
#873 merge-path flow tests (test_merge_path_flows_sprint37.gd).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 client/scripts/autoloads/sim_bridge.gd        |  32 +-
 client/scripts/protocol/protocol.gd           |  35 +-
 client/scripts/protocol/test_harness.gd       |   2 +-
 client/tests/test_anti_tedium.gd              |  24 +-
 client/tests/test_bug_report_ring_buffer.gd   |  10 +-
 client/tests/test_hub_teleport.gd             |   4 +-
 client/tests/test_input_roundtrip.gd          |   3 -
 client/tests/test_interaction_list.gd         |   4 +-
 client/tests/test_interaction_prompt.gd       |  29 +-
 client/tests/test_ipc_fixtures.gd             |   7 -
 client/tests/test_local_bridge.gd             |   2 +-
 .../tests/test_merge_path_flows_sprint37.gd   | 317 ++++++++++++++++++
 client/tests/test_p0_regressions.gd           |  78 ++++-
 client/tests/test_protocol.gd                 |  32 +-
 client/tests/test_protocol_bridge.gd          |  52 +--
 client/tests/test_protocol_v7.gd              |  23 +-
 client/tests/test_rendering.gd                |   2 -
 client/tests/test_signal_sprint24.gd          |  18 +-
 client/tests/test_sprint2_proof.gd            |   1 -
 client/tests/test_time_display_sprint17.gd    |   2 +-
 .../ui/meta/screens/loading/loading_screen.gd |   6 +-
 21 files changed, 490 insertions(+), 193 deletions(-)
 create mode 100644 client/tests/test_merge_path_flows_sprint37.gd

diff --git a/client/scripts/autoloads/sim_bridge.gd b/client/scripts/autoloads/sim_bridge.gd
index 1e8758502..0c297e519 100644
--- a/client/scripts/autoloads/sim_bridge.gd
+++ b/client/scripts/autoloads/sim_bridge.gd
@@ -246,13 +246,10 @@ func _process(delta: float) -> void:  # gdlint:disable=max-returns
 		if msg.is_empty():
 			return  # Not ready yet, continue polling
 
-		# Decode HandshakeMessage: { "protocol_version": N }
+		# Decode HandshakeMessage — D-192 (#875): protocol_version field dropped.
+		# Server sends {} or a minimal dict; only structural validity is required.
 		var decoded: Variant = Messagepack.decode(msg)
-		if (
-			decoded.status != null
-			or not (decoded.value is Dictionary)
-			or not decoded.value.has("protocol_version")
-		):
+		if decoded.status != null or not (decoded.value is Dictionary):
 			var reason := "Handshake decode failed: malformed HandshakeMessage"
 			push_error("SimBridge: %s" % reason)
 			handshake_failed.emit(reason)
@@ -260,18 +257,6 @@ func _process(delta: float) -> void:  # gdlint:disable=max-returns
 			_set_state(ConnectionState.ERROR)
 			return
 
-		var server_version: int = decoded.value["protocol_version"]
-		if server_version != Protocol.PROTOCOL_VERSION:
-			var reason := (
-				"Protocol version mismatch: server=%d, client=%d"
-				% [server_version, Protocol.PROTOCOL_VERSION]
-			)
-			push_error("SimBridge: %s" % reason)
-			handshake_failed.emit(reason)
-			_bridge.disconnect_from_server()
-			_set_state(ConnectionState.ERROR)
-			return
-
 		# Send startup message with world_seed and character appearance (#175, D-010/D-029, #718).
 		# Server blocks waiting for this before entering the tick loop.
 		var startup_bytes := Protocol.encode_startup_message(
@@ -296,7 +281,7 @@ func _process(delta: float) -> void:  # gdlint:disable=max-returns
 			_set_state(ConnectionState.ERROR)
 			return
 
-		handshake_complete.emit(server_version)
+		handshake_complete.emit(0)  # D-192: protocol_version field dropped; signal kept for API compat
 		_set_state(ConnectionState.CONNECTED)
 		# #646: Request full settings dump on connect — hydrates GameState.ai_enhanced_dialogue_enabled
 		# from server SQLite so the client reflects the authoritative persisted state (D-138).
@@ -464,6 +449,15 @@ func receive_bytes(bytes: PackedByteArray) -> void:
 			and _last_snapshot.get("settings_response") != null
 		):
 			snapshot["settings_response"] = _last_snapshot["settings_response"]
+		# #872: Carry forward bookmark_catalog (one-shot, consumed by main_menu._on_snapshot_received_for_catalog).
+		# Server sends catalog on tick 0 and after RequestBookmarkCatalog. If tick 0 and tick 1
+		# arrive in the same TCP batch, the inner receive loop overwrites _last_snapshot and the
+		# catalog is silently lost — this carry-forward prevents that race.
+		if (
+			snapshot.get("bookmark_catalog") == null
+			and _last_snapshot.get("bookmark_catalog") != null
+		):
+			snapshot["bookmark_catalog"] = _last_snapshot["bookmark_catalog"]
 	_last_snapshot = snapshot
 
 
diff --git a/client/scripts/protocol/protocol.gd b/client/scripts/protocol/protocol.gd
index f8230bfba..8180bf935 100644
--- a/client/scripts/protocol/protocol.gd
+++ b/client/scripts/protocol/protocol.gd
@@ -9,13 +9,6 @@ extends Node
 ##   Unit enum variants (no data) → bare strings ("MoveNorth", "Npc")
 ##   Data enum variants → single-element maps ({"UsePerceptionMode": "thermal"})
 
-## Protocol version — must match server PROTOCOL_VERSION in bridge/types.rs.
-## Reject snapshots where version != this value.
-## v20: adds settings_response field to ObserverSnapshot (#627, D-138).
-## v21: adds economy_snapshot field to ObserverSnapshot (#822, D-181).
-## v23: adds bookmark_catalog field to ObserverSnapshot (#614).
-const PROTOCOL_VERSION: int = 23
-
 # -- Decode: bytes from server → GDScript types --------------------------------
 
 
@@ -34,17 +27,6 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 		push_error("Protocol: snapshot missing required fields")
 		return null
 
-	# Version check: reject snapshots from incompatible server
-	var version: Variant = raw.get("version")
-	if version != PROTOCOL_VERSION:
-		push_error(
-			(
-				"Protocol: version mismatch (got %s, expected %s). Server and client are out of sync."
-				% [version, PROTOCOL_VERSION]
-			)
-		)
-		return null
-
 	var entities: Array[Dictionary] = []
 	var raw_entities: Array = raw["entities"]
 	var dropped := 0
@@ -67,7 +49,7 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 	# in any realistic scenario (would require ~29 billion years at 10 ticks/game-minute per D-031).
 	var tick: int = raw["tick"]
 
-	# version already checked above; game_time for HUD display
+	# game_time for HUD display
 	var game_time: Variant = raw.get("game_time")
 
 	# player_facing: FacingDirection is a unit enum → bare string in rmp_serde
@@ -223,6 +205,18 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 			"speaker_entity_id": int(raw_dr.get("speaker_entity_id", -1)),
 		}
 
+	# v8: gauntlet_mode and room_id (#496) — present only in Gauntlet sessions.
+	# gauntlet_mode is a bool flag; room_id is a String room identifier or absent.
+	# Snapshot handler (snapshot_handler.gd) reads these via snapshot.has() guards.
+	var gauntlet_mode: bool = false
+	var raw_gauntlet: Variant = raw.get("gauntlet_mode")
+	if raw_gauntlet == true:
+		gauntlet_mode = true
+	var room_id: Variant = null
+	var raw_room_id: Variant = raw.get("room_id")
+	if raw_room_id is String:
+		room_id = raw_room_id
+
 	# v9: conversation_events (#535, D-078) — overheard NPC-to-NPC dialogue lines.
 	# Each event carries pre-occluded text plus speaker/target attribution.
 	var conversation_events: Array = []
@@ -484,7 +478,6 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 		"tick": tick,
 		"entities": entities,
 		"decode_errors": dropped,
-		"version": version,
 		"game_time": game_time,
 		"player_facing": player_facing,
 		"player_stance": player_stance,
@@ -508,6 +501,8 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 		"current_ticker": current_ticker,
 		"settings_response": settings_response,
 		"bookmark_catalog": bookmark_catalog,
+		"gauntlet_mode": gauntlet_mode,
+		"room_id": room_id,
 	}
 
 
diff --git a/client/scripts/protocol/test_harness.gd b/client/scripts/protocol/test_harness.gd
index cf6cbffdf..b2b7e2e34 100644
--- a/client/scripts/protocol/test_harness.gd
+++ b/client/scripts/protocol/test_harness.gd
@@ -272,7 +272,7 @@ func snapshot() -> Dictionary:
 
 	return {
 		"tick": tick,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"game_time":
 		{
 			"day": 0,
diff --git a/client/tests/test_anti_tedium.gd b/client/tests/test_anti_tedium.gd
index 22d4766e0..b16d5ae48 100644
--- a/client/tests/test_anti_tedium.gd
+++ b/client/tests/test_anti_tedium.gd
@@ -15,7 +15,7 @@ extends GdUnitTestSuite
 const MAIN_SCENE = preload("res://scenes/main.tscn")
 
 var GauntletHUDScript = load("res://ui/gauntlet_hud.gd")
-var BugReportDialogScript = load("res://ui/bug_report_dialog.gd")
+const BugReportDialogScene = preload("res://ui/bug_report_dialog.tscn")
 var _instance: Node = null
 
 
@@ -47,7 +47,7 @@ func after_test() -> void:
 func _make_snapshot_bytes(overrides: Dictionary = {}) -> PackedByteArray:
 	var snapshot := {
 		"tick": overrides.get("tick", 1),
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": overrides.get("entities", [{
 			"entity_id": 1,
 			"x": 10.0,
@@ -92,8 +92,10 @@ func _make_gauntlet_hud() -> Control:
 
 
 func _make_bug_report_dialog() -> Control:
-	var dialog = Control.new()
-	dialog.set_script(BugReportDialogScript)
+	# Instantiate via .tscn — preserves the MetaScreen runtime stack.
+	# (Sprint 36 migrated bug_report_dialog.gd to extends MetaScreen; bare
+	# Control.new() + set_script() no longer satisfies the base contract.)
+	var dialog: Control = BugReportDialogScene.instantiate()
 	auto_free(dialog)
 	add_child(dialog)
 	return dialog
@@ -203,13 +205,15 @@ func test_snapshot_without_room_id_shows_no_gauntlet_ui() -> void:
 	var snapshot: Variant = SimBridge._last_snapshot
 	assert_that(snapshot).is_not_null()
 
-	# Snapshot should NOT contain gauntlet fields
-	assert_that(snapshot.has("room_id")).override_failure_message(
-		"Non-gauntlet snapshot must not contain room_id"
-	).is_false()
-	assert_that(snapshot.has("gauntlet_mode")).override_failure_message(
-		"Non-gauntlet snapshot must not contain gauntlet_mode"
+	# Non-gauntlet snapshot: gauntlet fields must be present with default values.
+	# (Protocol.decode_snapshot always decodes gauntlet fields; non-gauntlet
+	# snapshots produce false/null defaults. Check values, not key presence.)
+	assert_that(snapshot.get("gauntlet_mode", false)).override_failure_message(
+		"Non-gauntlet snapshot must decode gauntlet_mode == false"
 	).is_false()
+	assert_that(snapshot.get("room_id")).override_failure_message(
+		"Non-gauntlet snapshot must decode room_id == null"
+	).is_null()
 
 	# Apply to GameState — gauntlet-related state should not exist
 	GameState.apply_snapshot(snapshot)
diff --git a/client/tests/test_bug_report_ring_buffer.gd b/client/tests/test_bug_report_ring_buffer.gd
index eaacf3a1a..c8fc62f24 100644
--- a/client/tests/test_bug_report_ring_buffer.gd
+++ b/client/tests/test_bug_report_ring_buffer.gd
@@ -14,7 +14,7 @@ extends GdUnitTestSuite
 # Expected ring buffer capacity per spec.
 const EXPECTED_CAPACITY := 60
 
-var BugReportDialogScript = load("res://ui/bug_report_dialog.gd")
+const BugReportDialogScene = preload("res://ui/bug_report_dialog.tscn")
 
 
 func after_each() -> void:
@@ -35,8 +35,10 @@ func after_each() -> void:
 # -- Helpers -------------------------------------------------------------------
 
 func _make_dialog() -> Control:
-	var dialog = Control.new()
-	dialog.set_script(BugReportDialogScript)
+	# Instantiate via .tscn — preserves the MetaScreen runtime stack.
+	# (Sprint 36 migrated bug_report_dialog.gd to extends MetaScreen; bare
+	# Control.new() + set_script() no longer satisfies the base contract.)
+	var dialog: Control = BugReportDialogScene.instantiate()
 	auto_free(dialog)
 	add_child(dialog)
 	return dialog
@@ -52,7 +54,7 @@ func _make_input(tick: int, action: String = "MoveNorth") -> Dictionary:
 func _make_snapshot_json(tick: int) -> String:
 	return JSON.stringify({
 		"tick": tick,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	})
 
diff --git a/client/tests/test_hub_teleport.gd b/client/tests/test_hub_teleport.gd
index e39366f5b..3d1fedc58 100644
--- a/client/tests/test_hub_teleport.gd
+++ b/client/tests/test_hub_teleport.gd
@@ -15,7 +15,7 @@ const _THRESHOLD: float = 5.0  # Mirror of main.gd TELEPORT_DISTANCE_THRESHOLD
 
 var _gauntlet_snapshot := {
 	"tick": 1,
-	"version": Protocol.PROTOCOL_VERSION,
+	"version": 23,
 	"game_time": {"day": 0, "time_of_day": 100, "day_phase": "Morning", "tick_rate": "Full"},
 	"player_facing": "North",
 	"player_stance": "Walk",
@@ -36,7 +36,7 @@ var _gauntlet_snapshot := {
 
 var _normal_snapshot := {
 	"tick": 1,
-	"version": Protocol.PROTOCOL_VERSION,
+	"version": 23,
 	"game_time": {"day": 0, "time_of_day": 100, "day_phase": "Morning", "tick_rate": "Full"},
 	"player_facing": "North",
 	"player_stance": "Walk",
diff --git a/client/tests/test_input_roundtrip.gd b/client/tests/test_input_roundtrip.gd
index 3a99fec44..ac58eeb74 100644
--- a/client/tests/test_input_roundtrip.gd
+++ b/client/tests/test_input_roundtrip.gd
@@ -160,8 +160,6 @@ func test_interact_roundtrip() -> void:
 	# Server accepts it (currently a no-op) and responds with a valid snapshot.
 	var snapshot: Dictionary = await _send_and_receive("Interact", 0)
 
-	# Snapshot should be valid with correct protocol version
-	assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
 	assert_that(snapshot.entities.size()).is_greater(0)
 
 	# Player should be at start position (Interact doesn't move)
@@ -173,7 +171,6 @@ func test_interact_roundtrip() -> void:
 	# Send Interact again at next tick — server should still accept it
 	var snap2: Dictionary = await _send_and_receive("Interact", 1)
 	assert_that(snap2).is_not_null()
-	assert_that(snap2.version).is_equal(Protocol.PROTOCOL_VERSION)
 
 
 # -- Mixed sequence: movement then interact in one session ---------------------
diff --git a/client/tests/test_interaction_list.gd b/client/tests/test_interaction_list.gd
index 5f4cd3f3b..76f5c34fa 100644
--- a/client/tests/test_interaction_list.gd
+++ b/client/tests/test_interaction_list.gd
@@ -305,7 +305,7 @@ func test_contradicted_entity_verbs_decode() -> void:
 	# #422: NearbyInteraction.contradicted=true should be decodeable
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"nearby_interactions": [{
 			"entity_id": 2,
@@ -329,7 +329,7 @@ func test_object_type_verbs_decode() -> void:
 	# #421: ObjectType appears in NearbyInteraction.object_type
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"nearby_interactions": [{
 			"entity_id": 3,
diff --git a/client/tests/test_interaction_prompt.gd b/client/tests/test_interaction_prompt.gd
index 7e3557b3d..51cdfdb51 100644
--- a/client/tests/test_interaction_prompt.gd
+++ b/client/tests/test_interaction_prompt.gd
@@ -11,7 +11,7 @@ extends GdUnitTestSuite
 func test_protocol_decode_v4_with_nearby_interactions() -> void:
 	var raw := {
 		"tick": 10,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [
 			{"entity_id": 1, "x": 5.0, "y": 5.0, "z": 0, "kind": "Player",
 				"visibility": "Forward", "relationship": "Unknown", "observation": "Visible"},
@@ -46,7 +46,7 @@ func test_protocol_decode_v4_with_nearby_interactions() -> void:
 func test_protocol_decode_v4_no_nearby_interactions() -> void:
 	var raw := {
 		"tick": 5,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	}
 	var encoded = Messagepack.encode(raw)
@@ -57,7 +57,7 @@ func test_protocol_decode_v4_no_nearby_interactions() -> void:
 func test_protocol_decode_empty_nearby_interactions() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"nearby_interactions": [],
 	}
@@ -68,7 +68,7 @@ func test_protocol_decode_empty_nearby_interactions() -> void:
 func test_protocol_decode_interaction_missing_verbs() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"nearby_interactions": [{"entity_id": 2}],
 	}
@@ -79,7 +79,7 @@ func test_protocol_decode_interaction_missing_verbs() -> void:
 func test_protocol_decode_interaction_empty_verbs() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"nearby_interactions": [{"entity_id": 2, "entity_type": "Npc", "distance": 1, "verbs": []}],
 	}
@@ -90,7 +90,7 @@ func test_protocol_decode_interaction_empty_verbs() -> void:
 func test_protocol_decode_v4_entity_relationship() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [
 			{"entity_id": 1, "x": 5.0, "y": 5.0, "z": 0, "kind": "Npc",
 				"visibility": "Forward", "relationship": "Friendly", "observation": "Visible"},
@@ -100,17 +100,6 @@ func test_protocol_decode_v4_entity_relationship() -> void:
 	var snapshot = Protocol.decode_snapshot(encoded.value)
 	assert_that(snapshot.entities[0].relationship).is_equal("Friendly")
 
-func test_protocol_rejects_version_mismatch() -> void:
-	var raw := {
-		"tick": 5,
-		"version": 2,
-		"entities": [],
-	}
-	var encoded = Messagepack.encode(raw)
-	var snapshot = Protocol.decode_snapshot(encoded.value)
-	assert_that(snapshot).is_null()
-
-
 # -- GameState: nearby_interactions storage --
 
 func test_game_state_stores_nearby_interactions() -> void:
@@ -153,12 +142,6 @@ func test_sim_bridge_test_snapshot_interaction_at_range_2() -> void:
 	var snap = SimBridge._test_snapshot()
 	assert_that(snap.nearby_interactions.size()).is_equal(1)
 
-func test_sim_bridge_test_snapshot_protocol_version() -> void:
-	SimBridge.reset_test_state()
-	var snap = SimBridge._test_snapshot()
-	assert_that(snap.version).is_equal(Protocol.PROTOCOL_VERSION)
-
-
 # -- InteractionPrompt UI --
 
 func test_prompt_get_selected_verb_returns_first_kind() -> void:
diff --git a/client/tests/test_ipc_fixtures.gd b/client/tests/test_ipc_fixtures.gd
index 12594b279..d95085882 100644
--- a/client/tests/test_ipc_fixtures.gd
+++ b/client/tests/test_ipc_fixtures.gd
@@ -19,13 +19,6 @@ func _load_fixture(name: String) -> PackedByteArray:
 
 # -- snapshot_minimal ----------------------------------------------------------
 
-func test_fixture_snapshot_minimal_version() -> void:
-	var bytes = _load_fixture("snapshot_minimal")
-	var snapshot = Protocol.decode_snapshot(bytes)
-	assert_that(snapshot).is_not_null()
-	assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
-
-
 func test_fixture_snapshot_minimal_tick() -> void:
 	var bytes = _load_fixture("snapshot_minimal")
 	var snapshot = Protocol.decode_snapshot(bytes)
diff --git a/client/tests/test_local_bridge.gd b/client/tests/test_local_bridge.gd
index 9bc822498..afcfb4f14 100644
--- a/client/tests/test_local_bridge.gd
+++ b/client/tests/test_local_bridge.gd
@@ -95,7 +95,7 @@ func test_frame_encode_large_payload_length() -> void:
 
 func test_framed_protocol_snapshot_roundtrip() -> void:
 	# Encode a snapshot with Protocol, frame it, decode the frame, decode the snapshot
-	var snapshot_data := {"tick": 42, "version": Protocol.PROTOCOL_VERSION, "entities": []}
+	var snapshot_data := {"tick": 42, "version": 23, "entities": []}
 	var encoded: Variant = Messagepack.encode(snapshot_data)
 	assert_that(encoded.status).is_null()
 
diff --git a/client/tests/test_merge_path_flows_sprint37.gd b/client/tests/test_merge_path_flows_sprint37.gd
new file mode 100644
index 000000000..2038e0e0c
--- /dev/null
+++ b/client/tests/test_merge_path_flows_sprint37.gd
@@ -0,0 +1,317 @@
+## Sprint 37 — Scene-level merge-path UI flow tests (#873)
+##
+## Four flows that cover the critical paths through the pre-game UI.
+## These tests are the merge-gate mechanism added in the Sprint 36 retro:
+## regressions like #872 (New Game hang) must be caught here, not in post-merge
+## smoke tests.
+##
+## Pattern: load scene → simulate input via button.pressed.emit() or direct
+## handler call → assert terminal state. No pixel diffing, no xdotool.
+##
+## NOTE: Tests that end in a scene transition (change_scene_to_file) assert state
+## synchronously before the deferred transition fires. The test scene is
+## queue_freed in after_test() regardless.
+##
+## Reference: test_character_creation_sprint28.gd
+## Ticket: #873 | motivating regression: #872
+class_name TestMergePathFlowsSprint37
+extends GdUnitTestSuite
+
+const MAIN_MENU_SCENE_PATH := "res://scenes/main_menu.tscn"
+const CHAR_CREATE_SCENE_PATH := "res://scenes/character_creation.tscn"
+
+var _scene = null  # MainMenu or CharacterCreation — untyped, varies per test
+
+
+func before_test() -> void:
+	# Reset all shared state that these flows touch
+	SimBridge.disconnect_from_sim()
+	SimBridge._last_snapshot = null
+	SimBridge._outbound_buffer.clear()
+	GameState.bookmark_catalog = []
+	GameState.pending_load_path = ""
+	# Clear MetaStack from any leftover overlays to prevent push/pop ordering issues
+	MetaStack._stack.clear()
+
+
+func after_test() -> void:
+	if is_instance_valid(_scene):
+		_scene.queue_free()
+	_scene = null
+	SimBridge.disconnect_from_sim()
+	SimBridge._outbound_buffer.clear()
+	MetaStack._stack.clear()
+
+
+# -----------------------------------------------------------------------------
+# Helpers
+# -----------------------------------------------------------------------------
+
+func _load_main_menu() -> void:
+	var packed := load(MAIN_MENU_SCENE_PATH) as PackedScene
+	if packed == null:
+		push_warning("TestMergePathFlowsSprint37: main_menu.tscn not found — skipping")
+		return
+	_scene = packed.instantiate()
+	add_child(_scene)
+
+
+func _load_char_create() -> void:
+	var packed := load(CHAR_CREATE_SCENE_PATH) as PackedScene
+	if packed == null:
+		push_warning("TestMergePathFlowsSprint37: character_creation.tscn not found — skipping")
+		return
+	_scene = packed.instantiate()
+	# Seed required state so Start is not disabled (guard added in PR #134 / R2-Hoshe-1).
+	# Individual tests override these as needed.
+	_scene._selected_bookmark_id = "test-bookmark"
+	_scene._selected_location_id = "test-location"
+	if _scene.has_method("_update_start_btn_state"):
+		_scene._update_start_btn_state()
+	add_child(_scene)
+
+
+func _make_catalog_snapshot() -> Dictionary:
+	## Minimal valid snapshot with a bookmark_catalog for flow-1 testing.
+	return {
+		"tick": 0,
+		"version": 23,
+		"entities": [],
+		"game_time": {"day": 0, "time_of_day": 0, "day_phase": "Morning", "tick_rate": "Full"},
+		"player_facing": "North",
+		"player_stance": "Walk",
+		"player_inventory": [],
+		"visible_tiles": [],
+		"nearby_interactions": [],
+		"pending_recognitions": [],
+		"bookmark_catalog": {
+			"bookmarks": [
+				{
+					"id": "bm_tycoon_arion",
+					"title": "Arion Freight Broker",
+					"subtitle": "Start at Arion orbital",
+					"flavor": "Commodities and logistics.",
+					"default_location": "arion",
+					"allowed_locations": ["arion", "arion_low"],
+					"allowed_locations_cultures": ["arion"],
+					"career": "tycoon",
+					"starting_capital_tractus": 50000,
+				}
+			]
+		},
+	}
+
+
+# =============================================================================
+# Flow 1: main menu → new game → loading state → catalog received → resolved
+# =============================================================================
+# Regression guard for #872: New Game used to hang on "Connecting to simulation..."
+# because bookmark_catalog was overwritten in receive_bytes before poll_snapshot consumed it.
+# This test catches that regression by verifying the full state machine:
+# pressed → loading visible → catalog signal → loading dismissed.
+
+func test_new_game_shows_loading_screen() -> void:
+	## Pressing New Game must show the loading screen and set _waiting_for_catalog.
+	_load_main_menu()
+	if _scene == null:
+		return
+
+	assert_bool(_scene._waiting_for_catalog).override_failure_message(
+		"_waiting_for_catalog must be false before New Game is pressed"
+	).is_false()
+
+	# Press New Game via the button signal (same as real player input)
+	_scene._new_game_btn.pressed.emit()
+
+	assert_bool(_scene._waiting_for_catalog).override_failure_message(
+		"_waiting_for_catalog must be true after New Game pressed"
+	).is_true()
+	assert_that(_scene._loading_screen).override_failure_message(
+		"Loading screen instance must exist after New Game pressed"
+	).is_not_null()
+	assert_bool(_scene._loading_screen.visible).override_failure_message(
+		"Loading screen must be visible after New Game pressed"
+	).is_true()
+
+
+func test_new_game_catalog_snapshot_resolves_loading_state() -> void:
+	## When snapshot_received fires with a bookmark_catalog, the loading state must clear.
+	## This is the exact regression introduced in #872 — if the catalog is never delivered,
+	## _waiting_for_catalog stays true and the screen hangs forever.
+	_load_main_menu()
+	if _scene == null:
+		return
+
+	# Simulate the New Game press to set up the signal subscription and loading state.
+	# In test mode, connect_to_sim() immediately fires CONNECTED, which triggers
+	# _on_sim_state_changed_for_new_game and connects snapshot_received.
+	_scene._new_game_btn.pressed.emit()
+
+	assert_bool(_scene._waiting_for_catalog).override_failure_message(
+		"Precondition: _waiting_for_catalog must be true before catalog arrives"
+	).is_true()
+
+	# Deliver the catalog via the signal path (same path the server uses in live mode).
+	# snapshot_received is emitted here directly because in test mode poll_snapshot()
+	# uses the harness snapshot (no catalog). The carry-forward fix (#872) ensures
+	# this signal path also works correctly in live mode when ticks batch.
+	var catalog_snapshot := _make_catalog_snapshot()
+	SimBridge.snapshot_received.emit(catalog_snapshot)
+
+	# Terminal state: loading resolved
+	assert_bool(_scene._waiting_for_catalog).override_failure_message(
+		"_waiting_for_catalog must be false after catalog snapshot delivered — #872 regression"
+	).is_false()
+	assert_bool(GameState.bookmark_catalog.size() > 0).override_failure_message(
+		"GameState.bookmark_catalog must be populated after catalog snapshot applied"
+	).is_true()
+	assert_str(GameState.bookmark_catalog[0].get("id", "")).override_failure_message(
+		"Catalog entry must have the expected bookmark id"
+	).is_equal("bm_tycoon_arion")
+
+
+# =============================================================================
+# Flow 2: main menu → load game → save picker → save selected
+# =============================================================================
+
+func test_load_game_save_picker_shows_on_browse() -> void:
+	## Calling _on_load_game_browse() must show the save picker panel.
+	_load_main_menu()
+	if _scene == null:
+		return
+
+	assert_bool(_scene._load_panel.visible).override_failure_message(
+		"Load panel must be hidden before Load Game is pressed"
+	).is_false()
+
+	_scene._on_load_game_browse()
+
+	assert_bool(_scene._load_panel.visible).override_failure_message(
+		"Load panel must be visible after _on_load_game_browse()"
+	).is_true()
+
+
+func test_load_game_save_selection_sets_pending_load_path() -> void:
+	## Selecting a save entry must set GameState.pending_load_path for main.gd to consume.
+	_load_main_menu()
+	if _scene == null:
+		return
+
+	var mock_save := {
+		"game_id": "20260421-120000-abc123",
+		"newest_save": "quicksave.sav",
+	}
+
+	# Call _on_save_selected directly — mirrors what the generated save-list button does.
+	_scene._on_save_selected(mock_save)
+
+	assert_str(GameState.pending_load_path).override_failure_message(
+		"pending_load_path must be set to the selected save's full path"
+	).is_equal("user://saves/20260421-120000-abc123/quicksave.sav")
+
+
+# =============================================================================
+# Flow 3: character creation → submit → sim_bridge receives correct payload
+# =============================================================================
+
+func test_character_creation_submit_sends_confirm_bookmark_action() -> void:
+	## _on_start() must queue a ConfirmBookmark action with the selected bookmark
+	## and location IDs. This is the payload the server uses to initialize the run.
+	_load_char_create()
+	if _scene == null:
+		return
+
+	# Ensure SimBridge is connected so send_named_action doesn't silently drop the action
+	SimBridge.connect_to_sim()  # test mode: immediately CONNECTED
+
+	_scene._selected_bookmark_id = "bm_tycoon_arion"
+	_scene._selected_location_id = "arion"
+	if _scene.has_method("_update_start_btn_state"):
+		_scene._update_start_btn_state()
+
+	SimBridge._outbound_buffer.clear()
+	_scene._on_start()
+
+	var found := false
+	for entry in SimBridge._outbound_buffer:
+		if entry.get("action_name") == "ConfirmBookmark":
+			var data: Variant = entry.get("action_data")
+			if (
+				data is Dictionary
+				and data.get("bookmark_id") == "bm_tycoon_arion"
+				and data.get("starting_location_id") == "arion"
+			):
+				found = true
+				break
+	assert_bool(found).override_failure_message(
+		"_outbound_buffer must contain ConfirmBookmark{bookmark_id='bm_tycoon_arion', starting_location_id='arion'}"
+	).is_true()
+
+
+# =============================================================================
+# Flow 4: bookmark tab → select location → confirm → server gets bookmark action
+# =============================================================================
+
+func test_bookmark_tab_select_location_then_confirm_queues_action() -> void:
+	## Exercises the full selection path: picking a bookmark, picking a location, then
+	## confirming. Verifies the correct bookmark_id + starting_location_id reach the server.
+	## This is the flow the player actually takes — selection handlers must propagate
+	## to the outbound buffer correctly.
+
+	# Populate catalog before scene instantiation so _build_bookmark_cards() sees it
+	GameState.bookmark_catalog = [
+		{
+			"id": "bm_tycoon_arion",
+			"title": "Arion Freight Broker",
+			"subtitle": "Start at Arion orbital",
+			"flavor": "Commodities and logistics.",
+			"default_location": "arion",
+			"allowed_locations": ["arion", "arion_low"],
+			"allowed_locations_cultures": ["arion"],
+			"career": "tycoon",
+			"starting_capital_tractus": 50000,
+		}
+	]
+
+	_load_char_create()
+	if _scene == null:
+		return
+
+	SimBridge.connect_to_sim()  # test mode: immediately CONNECTED
+	SimBridge._outbound_buffer.clear()
+
+	# Simulate the player selecting the bookmark card
+	var bm: Dictionary = GameState.bookmark_catalog[0]
+	_scene._on_bookmark_selected(bm)
+
+	assert_str(_scene._selected_bookmark_id).override_failure_message(
+		"_on_bookmark_selected must update _selected_bookmark_id"
+	).is_equal("bm_tycoon_arion")
+	assert_str(_scene._selected_location_id).override_failure_message(
+		"_on_bookmark_selected must populate _selected_location_id from default_location"
+	).is_not_empty()
+
+	# Simulate the player picking a specific allowed location
+	_scene._on_location_selected("arion_low")
+
+	assert_str(_scene._selected_location_id).override_failure_message(
+		"_on_location_selected must update _selected_location_id"
+	).is_equal("arion_low")
+
+	# Confirm — sends the action to the server
+	_scene._on_start()
+
+	var found := false
+	for entry in SimBridge._outbound_buffer:
+		if entry.get("action_name") == "ConfirmBookmark":
+			var data: Variant = entry.get("action_data")
+			if (
+				data is Dictionary
+				and data.get("bookmark_id") == "bm_tycoon_arion"
+				and data.get("starting_location_id") == "arion_low"
+			):
+				found = true
+				break
+	assert_bool(found).override_failure_message(
+		"_outbound_buffer must contain ConfirmBookmark{bookmark_id='bm_tycoon_arion', starting_location_id='arion_low'}"
+	).is_true()
diff --git a/client/tests/test_p0_regressions.gd b/client/tests/test_p0_regressions.gd
index 845eec824..3b4855da0 100644
--- a/client/tests/test_p0_regressions.gd
+++ b/client/tests/test_p0_regressions.gd
@@ -1,10 +1,14 @@
-## Client P0 regression tests: guards for Bug #5 (monologue lost) and Bug #2 (camera drift).
+## Client P0 regression tests: guards for Bug #5 (monologue lost), Bug #2 (camera drift),
+## and Bug #872 (bookmark_catalog lost on batch receive).
 ## These must pass before any other client testing is meaningful.
 ##
 ## Bug #5: Monologue text lost when server sends snapshots faster than client
 ##         consumes them. Fix: carry-forward one-shot events in receive_bytes().
 ## Bug #2: Camera doesn't center at startup / drifts during pause. Fix: anchor
 ##         pattern with smoothing disabled until first snapshot applied.
+## Bug #872: bookmark_catalog silently dropped when tick 0 (with catalog) and tick 1
+##         (without catalog) arrive in the same TCP batch. Fix: carry-forward
+##         bookmark_catalog in receive_bytes() like save_result/settings_response.
 ##
 ## Spec ref: stig-round3.md Section 1 (P0 tests #1, #2).
 class_name TestP0Regressions
@@ -44,7 +48,7 @@ func after_test() -> void:
 func _make_snapshot_bytes(overrides: Dictionary = {}) -> PackedByteArray:
 	var snapshot := {
 		"tick": overrides.get("tick", 1),
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": overrides.get("entities", [{
 			"entity_id": 1,
 			"x": 10.0,
@@ -71,6 +75,8 @@ func _make_snapshot_bytes(overrides: Dictionary = {}) -> PackedByteArray:
 		snapshot["current_monologue"] = overrides["current_monologue"]
 	if overrides.has("current_dialogue"):
 		snapshot["current_dialogue"] = overrides["current_dialogue"]
+	if overrides.has("bookmark_catalog"):
+		snapshot["bookmark_catalog"] = overrides["bookmark_catalog"]
 	var result = Messagepack.encode(snapshot)
 	return result.value
 
@@ -229,3 +235,71 @@ func test_camera_anchored_after_pause_unpause() -> void:
 	# Camera still tracking player (position may have changed due to test_snapshot)
 	var player_pos := GameState.player_position * Constants.TILE_SIZE
 	assert_that(camera.global_position).is_equal(player_pos)
+
+
+# -- Bug #872: bookmark_catalog carry-forward ---------------------------------
+# Server sends bookmark_catalog on tick 0. If tick 1 arrives before poll_snapshot()
+# is called (same TCP batch), the inner receive loop overwrites _last_snapshot and
+# the catalog is silently lost. The carry-forward fix must preserve the catalog.
+
+func test_bookmark_catalog_not_lost_on_snapshot_overwrite() -> void:
+	var catalog := {
+		"bookmarks": [
+			{
+				"id": "bm_tycoon_arion",
+				"title": "Arion Freight Broker",
+				"subtitle": "Start at Arion orbital",
+				"flavor": "Commodities and logistics.",
+				"default_location": "arion",
+				"allowed_locations": ["arion"],
+				"allowed_locations_cultures": ["arion"],
+				"career": "tycoon",
+				"starting_capital_tractus": 50000,
+			}
+		]
+	}
+
+	# Tick 0: server sends catalog automatically after handshake
+	var bytes_tick0 := _make_snapshot_bytes({
+		"tick": 0,
+		"bookmark_catalog": catalog,
+	})
+	SimBridge.receive_bytes(bytes_tick0)
+
+	# Tick 1: server sends next tick WITHOUT catalog (fast server, same TCP batch)
+	var bytes_tick1 := _make_snapshot_bytes({"tick": 1})
+	SimBridge.receive_bytes(bytes_tick1)
+
+	# Assert: catalog must survive the overwrite — this is the Bug #872 fix.
+	assert_that(SimBridge._last_snapshot).is_not_null()
+	var bmc: Variant = SimBridge._last_snapshot.get("bookmark_catalog")
+	assert_that(bmc).is_not_null()
+	assert_that(bmc is Dictionary).is_true()
+	var bookmarks: Variant = bmc.get("bookmarks")
+	assert_that(bookmarks is Array).is_true()
+	assert_that((bookmarks as Array).size()).is_equal(1)
+	assert_that((bookmarks as Array)[0].get("id")).is_equal("bm_tycoon_arion")
+
+
+func test_bookmark_catalog_not_carried_forward_after_consumption() -> void:
+	# After poll_snapshot() consumes the catalog, the next snapshot without catalog
+	# must NOT carry it forward (it was already consumed and the scene transitioned).
+	var catalog := {
+		"bookmarks": [{"id": "bm_test", "title": "Test", "subtitle": "", "flavor": "",
+			"default_location": "arion", "allowed_locations": [], "allowed_locations_cultures": [],
+			"career": "tycoon", "starting_capital_tractus": 0}]
+	}
+	var bytes_tick0 := _make_snapshot_bytes({"tick": 0, "bookmark_catalog": catalog})
+	SimBridge.receive_bytes(bytes_tick0)
+
+	# Simulate poll_snapshot() consumption — sets _last_snapshot to null
+	var snapshot = SimBridge._last_snapshot
+	SimBridge._last_snapshot = null
+	assert_that(snapshot).is_not_null()
+
+	# Next snapshot arrives without catalog — no carry-forward should happen
+	var bytes_tick1 := _make_snapshot_bytes({"tick": 1})
+	SimBridge.receive_bytes(bytes_tick1)
+
+	var bmc: Variant = SimBridge._last_snapshot.get("bookmark_catalog")
+	assert_that(bmc).is_null()
diff --git a/client/tests/test_protocol.gd b/client/tests/test_protocol.gd
index cb53e9d55..be744df71 100644
--- a/client/tests/test_protocol.gd
+++ b/client/tests/test_protocol.gd
@@ -188,7 +188,7 @@ func test_decode_snapshot_malformed_entities_counted() -> void:
 	# Snapshot with one valid and one malformed entity — decode_errors should count the bad one
 	var raw := {
 		"tick": 7,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [
 			{"entity_id": 1, "x": 5.0, "y": 10.0, "z": 0, "kind": "Npc"},
 			{"entity_id": 2, "broken": true},  # Missing required fields
@@ -282,7 +282,6 @@ func test_decode_snapshot_v2_full() -> void:
 
 	assert_that(snapshot).is_not_null()
 	assert_that(snapshot.tick).is_equal(500)
-	assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
 
 	# game_time
 	assert_that(snapshot.game_time).is_not_null()
@@ -309,7 +308,6 @@ func test_existing_fixtures_have_v2_fields() -> void:
 		var bytes = _load_fixture(fixture_name)
 		var snapshot = Protocol.decode_snapshot(bytes)
 		assert_that(snapshot).is_not_null()
-		assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
 		assert_that(snapshot.player_facing).is_equal("North")
 		assert_that(snapshot.game_time).is_not_null()
 
@@ -324,30 +322,6 @@ func test_multi_entity_visibility_sectors() -> void:
 	assert_that(snapshot.entities[3].visibility).is_equal("Forward")
 
 
-# -- Version enforcement (strict PROTOCOL_VERSION check) --------------------
-
-func test_decode_snapshot_rejects_missing_version() -> void:
-	# Snapshot without version field → rejected by strict version check
-	var v1_raw := {"tick": 10, "entities": [
-		{"entity_id": 1, "x": 5.0, "y": 5.0, "z": 0, "kind": "Player"},
-	]}
-	var encoded: Variant = Messagepack.encode(v1_raw)
-	assert_that(encoded.status).is_null()
-
-	var snapshot: Variant = Protocol.decode_snapshot(encoded.value)
-	assert_that(snapshot).is_null()
-
-
-func test_decode_snapshot_rejects_old_version() -> void:
-	# Snapshot with version 2 → rejected by strict version check
-	var old_raw := {"tick": 10, "version": 2, "entities": []}
-	var encoded: Variant = Messagepack.encode(old_raw)
-	assert_that(encoded.status).is_null()
-
-	var snapshot: Variant = Protocol.decode_snapshot(encoded.value)
-	assert_that(snapshot).is_null()
-
-
 # -- Batch input fixture (D-030 Layer 1 bidirectional symmetry) ----------------
 
 func test_decode_batch_input_fixture() -> void:
@@ -391,7 +365,7 @@ func test_decode_snapshot_with_bookmark_catalog() -> void:
 	# Hand-built dict — fixture generation requires server work, skip round-trip (#614).
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"bookmark_catalog": {
 			"bookmarks": [
@@ -451,7 +425,7 @@ func test_decode_snapshot_no_bookmark_catalog_is_null() -> void:
 	# Snapshot without bookmark_catalog key → field should be null.
 	var raw := {
 		"tick": 2,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	}
 	var encoded: Variant = Messagepack.encode(raw)
diff --git a/client/tests/test_protocol_bridge.gd b/client/tests/test_protocol_bridge.gd
index 383a355e0..91b9b393d 100644
--- a/client/tests/test_protocol_bridge.gd
+++ b/client/tests/test_protocol_bridge.gd
@@ -24,33 +24,12 @@ func _load_fixture(name: String) -> PackedByteArray:
 	return file.get_buffer(file.get_length())
 
 
-# -- Protocol version upgrade -------------------------------------------------
-# Tautological "PROTOCOL_VERSION == N" assertions deleted: they assert a constant
-# equals its own literal, fail mechanically on every protocol bump, and have
-# never caught a real bug. Mismatch handling is exercised by test_rejects_version_6
-# below; field-presence is exercised by the per-version decode tests.
-
-func test_fixtures_at_protocol_version_8() -> void:
-	# NOTE: These binary fixtures embed version 8 and are rejected by the version
-	# mismatch guard in decode_snapshot(). This test is pre-existing broken since v9+.
-	# Fixtures need regeneration via `make fixtures-gauntlet` to match current protocol.
-	# Skipping rather than deleting to preserve the fixture round-trip pattern.
-	pass
-
-
-func test_rejects_version_6() -> void:
-	var raw := {"tick": 1, "version": 6, "entities": []}
-	var encoded = Messagepack.encode(raw)
-	var snapshot = Protocol.decode_snapshot(encoded.value)
-	assert_that(snapshot).is_null()
-
-
 # -- player_stance decode (D-053) ---------------------------------------------
 
 func test_decode_player_stance_walk() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"player_stance": "Walk",
 		"player_inventory": [],
@@ -64,7 +43,7 @@ func test_decode_player_stance_walk() -> void:
 func test_decode_player_stance_sprint() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"player_stance": "Sprint",
 		"player_inventory": [],
@@ -77,7 +56,7 @@ func test_decode_player_stance_sprint() -> void:
 func test_decode_player_stance_careful() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"player_stance": "Careful",
 		"player_inventory": [],
@@ -90,7 +69,7 @@ func test_decode_player_stance_careful() -> void:
 func test_decode_player_stance_crouch() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"player_stance": "Crouch",
 		"player_inventory": [],
@@ -104,7 +83,7 @@ func test_decode_player_stance_missing_defaults_to_walk() -> void:
 	# v6 snapshot without player_stance → should default to "Walk"
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	}
 	var encoded = Messagepack.encode(raw)
@@ -118,7 +97,7 @@ func test_decode_player_stance_missing_defaults_to_walk() -> void:
 func test_decode_empty_inventory() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"player_stance": "Walk",
 		"player_inventory": [],
@@ -132,7 +111,7 @@ func test_decode_smuggler_inventory_3_items() -> void:
 	# D-065: smuggler carries 3 specific items
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"player_stance": "Walk",
 		"player_inventory": [
@@ -161,7 +140,7 @@ func test_decode_full_9_slot_inventory() -> void:
 		items.append({"item_id": 100 + i, "name": "Item %d" % i, "slot": i})
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"player_inventory": items,
 	}
@@ -177,7 +156,7 @@ func test_decode_full_9_slot_inventory() -> void:
 func test_decode_inventory_missing_defaults_to_empty() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	}
 	var encoded = Messagepack.encode(raw)
@@ -188,7 +167,7 @@ func test_decode_inventory_missing_defaults_to_empty() -> void:
 func test_decode_inventory_skips_malformed_items() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"player_inventory": [
 			{"item_id": 100, "name": "Valid Item", "slot": 0},
@@ -209,7 +188,7 @@ func test_decode_inventory_skips_malformed_items() -> void:
 func test_decode_inventory_item_slot_defaults_to_zero() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"player_inventory": [
 			{"item_id": 100, "name": "No Slot"},
@@ -281,12 +260,6 @@ func test_sim_bridge_test_snapshot_has_player_inventory() -> void:
 	assert_that(snap.player_inventory is Array).is_true()
 
 
-func test_sim_bridge_test_snapshot_uses_current_protocol_version() -> void:
-	SimBridge.reset_test_state()
-	var snap = SimBridge._test_snapshot()
-	assert_that(snap.version).is_equal(Protocol.PROTOCOL_VERSION)
-
-
 # -- Fixture: v6 snapshots include new fields ----------------------------------
 
 func test_fixture_snapshots_have_v6_defaults() -> void:
@@ -334,7 +307,7 @@ func test_full_v6_snapshot_decode() -> void:
 	# Simulate a realistic v6 snapshot with all fields populated
 	var raw := {
 		"tick": 100,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"game_time": {"day": 1, "time_of_day": 720, "day_phase": "Evening", "tick_rate": "Full"},
 		"player_facing": "Southeast",
 		"player_stance": "Careful",
@@ -367,7 +340,6 @@ func test_full_v6_snapshot_decode() -> void:
 
 	assert_that(snapshot).is_not_null()
 	assert_that(snapshot.tick).is_equal(100)
-	assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
 	assert_that(snapshot.player_facing).is_equal("Southeast")
 	assert_that(snapshot.player_stance).is_equal("Careful")
 	assert_that(snapshot.player_inventory.size()).is_equal(3)
diff --git a/client/tests/test_protocol_v7.gd b/client/tests/test_protocol_v7.gd
index 649036aee..16cd0987a 100644
--- a/client/tests/test_protocol_v7.gd
+++ b/client/tests/test_protocol_v7.gd
@@ -12,7 +12,7 @@ extends GdUnitTestSuite
 func test_decode_pending_recognitions_basic() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"pending_recognitions": [
 			{"entity_id": 100, "x": 13.5, "y": 12.5, "z": 0, "remaining_ticks": 4, "total_delay_ticks": 6},
@@ -33,7 +33,7 @@ func test_decode_pending_recognitions_basic() -> void:
 func test_decode_pending_recognitions_empty() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"pending_recognitions": [],
 	}
@@ -45,7 +45,7 @@ func test_decode_pending_recognitions_empty() -> void:
 func test_decode_pending_recognitions_missing_defaults_empty() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	}
 	var encoded = Messagepack.encode(raw)
@@ -56,7 +56,7 @@ func test_decode_pending_recognitions_missing_defaults_empty() -> void:
 func test_decode_pending_recognitions_skips_malformed() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"pending_recognitions": [
 			{"entity_id": 100, "x": 13.5, "y": 12.5, "z": 0, "remaining_ticks": 4, "total_delay_ticks": 6},
@@ -76,7 +76,7 @@ func test_decode_pending_recognitions_defaults() -> void:
 	# remaining_ticks and total_delay_ticks default to 0 and 1
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"pending_recognitions": [
 			{"entity_id": 100, "x": 5.0, "y": 5.0},
@@ -94,7 +94,7 @@ func test_decode_pending_recognitions_defaults() -> void:
 func test_decode_current_dialogue() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"current_dialogue": {
 			"npc_name": "Kael",
@@ -123,7 +123,7 @@ func test_decode_current_dialogue() -> void:
 func test_decode_current_dialogue_missing_is_null() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	}
 	var encoded = Messagepack.encode(raw)
@@ -136,7 +136,7 @@ func test_decode_current_dialogue_options_default_fields() -> void:
 	# response_id and priority default when absent
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"current_dialogue": {
 			"speech": "Just speech.",
@@ -158,7 +158,7 @@ func test_decode_current_dialogue_options_default_fields() -> void:
 func test_decode_current_dialogue_confrontation_option() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"current_dialogue": {
 			"npc_name": "Sera",
@@ -179,7 +179,7 @@ func test_decode_current_dialogue_confrontation_option() -> void:
 func test_decode_current_dialogue_skips_malformed_options() -> void:
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"current_dialogue": {
 			"npc_name": "Sera",
@@ -332,7 +332,7 @@ func test_insert_color_constants_exist() -> void:
 func test_full_v7_snapshot_decode() -> void:
 	var raw := {
 		"tick": 200,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"game_time": {"day": 2, "time_of_day": 1000, "day_phase": "Evening", "tick_rate": "Full"},
 		"player_facing": "West",
 		"player_stance": "Careful",
@@ -362,7 +362,6 @@ func test_full_v7_snapshot_decode() -> void:
 
 	assert_that(snapshot).is_not_null()
 	assert_that(snapshot.tick).is_equal(200)
-	assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
 	assert_that(snapshot.player_facing).is_equal("West")
 	assert_that(snapshot.player_stance).is_equal("Careful")
 	assert_that(snapshot.player_inventory.size()).is_equal(1)
diff --git a/client/tests/test_rendering.gd b/client/tests/test_rendering.gd
index 399283250..3a7f85ff3 100644
--- a/client/tests/test_rendering.gd
+++ b/client/tests/test_rendering.gd
@@ -174,8 +174,6 @@ func test_sim_bridge_test_tiles_contain_all_types() -> void:
 func test_sim_bridge_test_snapshot_has_v2_fields() -> void:
 	SimBridge.reset_test_state()
 	var snap = SimBridge._test_snapshot()
-	assert_that(snap.has("version")).is_true()
-	assert_that(snap.version).is_equal(Protocol.PROTOCOL_VERSION)
 	assert_that(snap.has("game_time")).is_true()
 	assert_that(snap.has("player_facing")).is_true()
 	assert_that(snap.has("visible_tiles")).is_true()
diff --git a/client/tests/test_signal_sprint24.gd b/client/tests/test_signal_sprint24.gd
index 60f16c0cf..3bdeed7aa 100644
--- a/client/tests/test_signal_sprint24.gd
+++ b/client/tests/test_signal_sprint24.gd
@@ -80,7 +80,7 @@ func test_protocol_decode_includes_triangle_crisis_events_field() -> void:
 	# decode_snapshot() must return a "triangle_crisis_events" key (#590).
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"triangle_crisis_events": [{"triangle_id": 42}],
 	}
@@ -102,7 +102,7 @@ func test_protocol_decode_triangle_crisis_events_empty_array() -> void:
 	# When no events are present, field is present and empty.
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"triangle_crisis_events": [],
 	}
@@ -117,7 +117,7 @@ func test_protocol_decode_triangle_crisis_events_absent_returns_empty() -> void:
 	# When server doesn't send field (pre-#589), field defaults to empty array.
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	}
 	var encoded = Messagepack.encode(raw)
@@ -167,7 +167,7 @@ func test_protocol_decode_includes_current_ticker_field() -> void:
 	# decode_snapshot() must return a "current_ticker" key (#592).
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"current_ticker": {"id": "ticker_001", "text": "Station systems nominal.", "category": "System"},
 	}
@@ -187,7 +187,7 @@ func test_protocol_decode_current_ticker_null_when_absent() -> void:
 	# When server doesn't send current_ticker (player outside bar zone), field is null.
 	var raw := {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	}
 	var encoded = Messagepack.encode(raw)
@@ -210,7 +210,7 @@ func test_news_ticker_hidden_when_snapshot_has_no_ticker() -> void:
 	# Snapshot with no current_ticker (player outside bar zone).
 	GameState.current_snapshot = {
 		"tick": 1,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 	}
 	ticker.update_from_state()
@@ -229,7 +229,7 @@ func test_news_ticker_visible_when_snapshot_has_ticker() -> void:
 
 	GameState.current_snapshot = {
 		"tick": 2,
-		"version": Protocol.PROTOCOL_VERSION,
+		"version": 23,
 		"entities": [],
 		"current_ticker": {"id": "t1", "text": "Station systems nominal.", "category": "System"},
 	}
@@ -249,7 +249,7 @@ func test_news_ticker_hides_when_ticker_becomes_null() -> void:
 
 	# Show it first.
 	GameState.current_snapshot = {
-		"tick": 1, "version": Protocol.PROTOCOL_VERSION, "entities": [],
+		"tick": 1, "version": 23, "entities": [],
 		"current_ticker": {"id": "t1", "text": "Breaking news.", "category": "System"},
 	}
 	ticker.update_from_state()
@@ -257,7 +257,7 @@ func test_news_ticker_hides_when_ticker_becomes_null() -> void:
 
 	# Null current_ticker — player left the bar zone.
 	GameState.current_snapshot = {
-		"tick": 2, "version": Protocol.PROTOCOL_VERSION, "entities": [],
+		"tick": 2, "version": 23, "entities": [],
 	}
 	ticker.update_from_state()
 	assert_bool(ticker.visible).override_failure_message(
diff --git a/client/tests/test_sprint2_proof.gd b/client/tests/test_sprint2_proof.gd
index d786be082..b27cedd7f 100644
--- a/client/tests/test_sprint2_proof.gd
+++ b/client/tests/test_sprint2_proof.gd
@@ -132,7 +132,6 @@ func skip_test_proof_player_moves_and_v2_snapshot() -> void:
 	assert_float(player.y).is_equal_approx(15.5, 0.001)
 
 	# v4 protocol fields present
-	assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
 	assert_that(snapshot.player_facing).is_equal("North")
 	assert_that(snapshot.game_time).is_not_null()
 
diff --git a/client/tests/test_time_display_sprint17.gd b/client/tests/test_time_display_sprint17.gd
index 6d2162045..57f49ea3b 100644
--- a/client/tests/test_time_display_sprint17.gd
+++ b/client/tests/test_time_display_sprint17.gd
@@ -291,7 +291,7 @@ func test_hud_time_row_updates_after_process() -> void:
 	add_child(instance)
 
 	GameState.apply_snapshot({
-		"tick": 1, "version": Protocol.PROTOCOL_VERSION, "entities": [],
+		"tick": 1, "version": 23, "entities": [],
 		"game_time": {"day": 0, "time_of_day": 720, "day_phase": "Afternoon", "tick_rate": "Full"},
 	})
 	instance._process(0.016)
diff --git a/client/ui/meta/screens/loading/loading_screen.gd b/client/ui/meta/screens/loading/loading_screen.gd
index 240de1d0e..a307e2518 100644
--- a/client/ui/meta/screens/loading/loading_screen.gd
+++ b/client/ui/meta/screens/loading/loading_screen.gd
@@ -39,13 +39,9 @@ func _build_ui() -> void:
 	_label.mouse_filter = Control.MOUSE_FILTER_IGNORE
 	add_child(_label)
 
-	# client_ver and proto_ver are independent — project.yaml version is the client release,
-	# Protocol.PROTOCOL_VERSION is the wire protocol. Mismatches between builds are visible
-	# only to the observer reading the loading-screen label; a future ticket will surface them.
 	var client_ver := _read_client_version()
-	var proto_ver: int = Protocol.PROTOCOL_VERSION
 	_version_label = Label.new()
-	_version_label.text = "v%s  ·  protocol %d" % [client_ver, proto_ver]
+	_version_label.text = "v%s" % [client_ver]
 	_version_label.add_theme_font_size_override("font_size", VERSION_FONT_SIZE)
 	_version_label.add_theme_color_override("font_color", VERSION_COLOR)
 	_version_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER