diff --git a/sim/rl/jax_core/__init__.py b/sim/rl/jax_core/__init__.py
new file mode 100644
index 0000000..99d5a87
--- /dev/null
+++ b/sim/rl/jax_core/__init__.py
@@ -0,0 +1,11 @@
+"""JAX-accelerated simulation core for PHANTOM environment."""
+from .transitions import TransitionData, compile_transitions, fallback_transitions, JAX_AVAILABLE
+from .simulation import SessionBatch, SimResult, sample_sessions, compute_metrics
+from .features import session_features, compute_session_transitions
+from .separability import compute_divergences, estimate_alpha_batch
+
+__all__ = [
+    "JAX_AVAILABLE", "TransitionData", "compile_transitions", "fallback_transitions",
+    "SessionBatch", "SimResult", "sample_sessions", "compute_metrics",
+    "session_features", "compute_session_transitions", "compute_divergences", "estimate_alpha_batch",
+]