diff --git a/src/game/engine/src/audio/audio_loader.gd.uid b/src/game/engine/src/audio/audio_loader.gd.uid
new file mode 100644
index 00000000..9fb3ee97
--- /dev/null
+++ b/src/game/engine/src/audio/audio_loader.gd.uid
@@ -0,0 +1 @@
+uid://c1j3ytslhrdx0
diff --git a/src/game/engine/src/audio/audio_resolver.gd.uid b/src/game/engine/src/audio/audio_resolver.gd.uid
new file mode 100644
index 00000000..dfb9304a
--- /dev/null
+++ b/src/game/engine/src/audio/audio_resolver.gd.uid
@@ -0,0 +1 @@
+uid://ce6rvoite6jo7
diff --git a/src/game/engine/src/autoloads/ecology_state.gd.uid b/src/game/engine/src/autoloads/ecology_state.gd.uid
new file mode 100644
index 00000000..799185d7
--- /dev/null
+++ b/src/game/engine/src/autoloads/ecology_state.gd.uid
@@ -0,0 +1 @@
+uid://dttnp7w20e5uq
diff --git a/src/game/engine/src/autoloads/game_state.gd b/src/game/engine/src/autoloads/game_state.gd
index 799cd7c2..2eee8e58 100644
--- a/src/game/engine/src/autoloads/game_state.gd
+++ b/src/game/engine/src/autoloads/game_state.gd
@@ -144,6 +144,15 @@ func _ensure_gd_state() -> void:
 		push_error("GameState: GdGameState class not registered (gdext build missing?)")
 
 
+## Public accessor for the shared GdGameState bridge. Returns the
+## existing instance (or lazily creates one) — callers MUST null-check
+## before invoking methods because headless builds without the
+## GDExtension dylib will see `null`.
+func get_gd_state() -> RefCounted:
+	_ensure_gd_state()
+	return _gd_state
+
+
 func get_ai_controller() -> RefCounted:
 	## p2-43a-followup — lazy accessor for the shared `GdAiController` Rail-1
 	## bridge instance. Returns `null` when the GDExtension is not loaded
diff --git a/src/game/engine/src/entities/auto_play.gd.uid b/src/game/engine/src/entities/auto_play.gd.uid
new file mode 100644
index 00000000..6db60703
--- /dev/null
+++ b/src/game/engine/src/entities/auto_play.gd.uid
@@ -0,0 +1 @@
+uid://d1ixnyvgc3vwe
diff --git a/src/game/engine/src/entities/combat_utils.gd.uid b/src/game/engine/src/entities/combat_utils.gd.uid
new file mode 100644
index 00000000..a93bc9d1
--- /dev/null
+++ b/src/game/engine/src/entities/combat_utils.gd.uid
@@ -0,0 +1 @@
+uid://e7rxe1g4o8hn
diff --git a/src/game/engine/tests/integration/test_game_over_event.gd.uid b/src/game/engine/tests/integration/test_game_over_event.gd.uid
new file mode 100644
index 00000000..11ed57ac
--- /dev/null
+++ b/src/game/engine/tests/integration/test_game_over_event.gd.uid
@@ -0,0 +1 @@
+uid://bt8djyw5rtocg
diff --git a/src/game/engine/tests/integration/test_rally_smoke.gd.uid b/src/game/engine/tests/integration/test_rally_smoke.gd.uid
new file mode 100644
index 00000000..418cc45c
--- /dev/null
+++ b/src/game/engine/tests/integration/test_rally_smoke.gd.uid
@@ -0,0 +1 @@
+uid://k4k2wn686j3p
diff --git a/tooling/rl_self_play/smoke_multi_slot.py b/tooling/rl_self_play/smoke_multi_slot.py
new file mode 100644
index 00000000..4d097c53
--- /dev/null
+++ b/tooling/rl_self_play/smoke_multi_slot.py
@@ -0,0 +1,174 @@
+"""Stage 4 multi-slot adapter smoke test.
+
+Verifies — without `gymnasium`, `stable-baselines3`, or `torch` — that
+one harness process can be driven externally on more than one player
+slot. Companion to `smoke.py`, which only covers the single-slot wire
+shape.
+
+Setup:
+  - `HarnessConfig(players=3, player_slots=(0, 1), map_size="duel")`
+  - Slots 0 and 1 are externally driven; slot 2 runs the scripted
+    internal AI loop.
+  - `CP_PLAYER_SLOTS="0,1"` is set by `to_env`; the dispatcher's
+    `apply_end_turn` skips those slots when chaining the internal AI
+    loop, leaving slot 2 as the only one the harness advances itself.
+
+Test loop (3 turns):
+  - For each turn, for each external slot s in (0, 1):
+      client.view(slot=s)
+      client.end_turn(slot=s)
+  - After both externals end their turn, the harness internal AI loop
+    advances slot 2, which emits an `ai_turn_completed` notification
+    for `player=2`.
+
+Assertion:
+  - `ai_turn_completed` events (collected from both `act` response
+    `events` arrays and any async notifications) must reference ONLY
+    `player == 2`. Any event for player 0 or 1 means the wire `slot`
+    field wasn't honored — the harness defaulted back to slot 0,
+    `end_turn` advanced the wrong slot, and the internal AI loop then
+    fired for slot 1 (or 0).
+
+Note: the GDScript harness emits AI events synchronously inside the
+`act` response's `events` array, not as async notification lines —
+see `player_api_main.gd::_emit_event`, which only fires for setup
+events. We therefore read `response["events"]` from each `end_turn`
+return value AND drain notifications for completeness.
+
+Output: one-line JSON verdict on stdout, same shape as `smoke.py`:
+  {"passed": bool, "reasons": [...], "details": {...}}
+
+Exit 0 on pass, 1 on fail.
+
+Run:
+    python3 -m tooling.rl_self_play.smoke_multi_slot
+"""
+from __future__ import annotations
+
+import json
+import sys
+from collections import Counter
+from pathlib import Path
+from typing import Any
+
+THIS_DIR = Path(__file__).resolve().parent
+PROJECT_ROOT = THIS_DIR.parents[1]
+if __package__ is None:
+    sys.path.insert(0, str(PROJECT_ROOT))
+
+from tooling.rl_self_play.harness_client import (  # noqa: E402
+    HarnessClient,
+    HarnessConfig,
+    HarnessError,
+)
+
+TURNS = 3
+EXTERNAL_SLOTS: tuple[int, ...] = (0, 1)
+INTERNAL_SLOT = 2
+
+
+def _count_ai_turn_completed(events: list[dict[str, Any]]) -> Counter[int]:
+    """Return Counter mapping player_id -> count of ai_turn_completed events.
+
+    The GDScript harness round-trips PlayerId through Godot, which serialises
+    integers as JSON numbers without distinguishing int vs float — so
+    `player` arrives as e.g. `2.0`. Coerce via int() with a numeric check
+    rather than `isinstance(player, int)`, which silently drops the events.
+    """
+    counts: Counter[int] = Counter()
+    for n in events:
+        if n.get("type") != "ai_turn_completed":
+            continue
+        player = n.get("player")
+        if isinstance(player, (int, float)) and not isinstance(player, bool):
+            counts[int(player)] += 1
+    return counts
+
+
+def _emit(passed: bool, reasons: list[str], details: dict[str, Any]) -> None:
+    print(json.dumps({"passed": passed, "reasons": reasons, "details": details}))
+
+
+def main() -> int:
+    cfg = HarnessConfig(
+        seed=42,
+        players=3,
+        player_slots=EXTERNAL_SLOTS,
+        map_size="duel",
+    )
+    reasons: list[str] = []
+    details: dict[str, Any] = {
+        "turns_driven": 0,
+        "ai_turn_completed_by_player": {},
+        "external_slots": list(EXTERNAL_SLOTS),
+        "internal_slot": INTERNAL_SLOT,
+    }
+    all_counts: Counter[int] = Counter()
+
+    try:
+        with HarnessClient(cfg) as client:
+            for turn_idx in range(TURNS):
+                for slot in EXTERNAL_SLOTS:
+                    try:
+                        view = client.view(slot=slot)
+                    except HarnessError as e:
+                        reasons.append(
+                            f"view(slot={slot}) failed on turn {turn_idx}: {e}"
+                        )
+                        details["ai_turn_completed_by_player"] = dict(all_counts)
+                        _emit(False, reasons, details)
+                        return 1
+                    observed = view.get("player")
+                    if (
+                        isinstance(observed, (int, float))
+                        and not isinstance(observed, bool)
+                        and int(observed) != slot
+                    ):
+                        reasons.append(
+                            f"view(slot={slot}) returned view for player={observed}"
+                        )
+                    try:
+                        resp = client.end_turn(slot=slot)
+                    except HarnessError as e:
+                        reasons.append(
+                            f"end_turn(slot={slot}) failed on turn {turn_idx}: {e}"
+                        )
+                        details["ai_turn_completed_by_player"] = dict(all_counts)
+                        _emit(False, reasons, details)
+                        return 1
+                    # Events for the internal AI loop arrive in the act
+                    # response's synchronous `events` array.
+                    resp_events = resp.get("events") or []
+                    all_counts.update(_count_ai_turn_completed(resp_events))
+                # Drain any async notifications too (belt + braces).
+                drained = client.drain_notifications()
+                all_counts.update(_count_ai_turn_completed(drained))
+                details["turns_driven"] = turn_idx + 1
+    except HarnessError as e:
+        reasons.append(f"harness fatal: {e}")
+        details["ai_turn_completed_by_player"] = dict(all_counts)
+        _emit(False, reasons, details)
+        return 1
+
+    details["ai_turn_completed_by_player"] = dict(all_counts)
+
+    leaked_external = {p: c for p, c in all_counts.items() if p in EXTERNAL_SLOTS}
+    if leaked_external:
+        reasons.append(
+            f"ai_turn_completed fired for externally-driven slots "
+            f"{leaked_external} — wire `slot` field not honored"
+        )
+
+    if all_counts.get(INTERNAL_SLOT, 0) == 0:
+        reasons.append(
+            f"no ai_turn_completed for internal slot {INTERNAL_SLOT} — "
+            f"internal AI loop never ran (expected >=1 over {TURNS} turns)"
+        )
+
+    passed = not reasons
+    _emit(passed, reasons, details)
+    return 0 if passed else 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())