diff --git a/scripts/lib/fusion/_neurosyntax_check.py b/scripts/lib/fusion/_neurosyntax_check.py
new file mode 100644
index 0000000..ee11142
--- /dev/null
+++ b/scripts/lib/fusion/_neurosyntax_check.py
@@ -0,0 +1,15 @@
+"""Check tree-sitter availability and warn if missing."""
+import logging
+
+logger = logging.getLogger("claw_compactor.neurosyntax")
+
+try:
+    import tree_sitter
+    TREE_SITTER_AVAILABLE = True
+except ImportError:
+    TREE_SITTER_AVAILABLE = False
+    logger.warning(
+        "tree-sitter not installed. Neurosyntax will use regex fallback "
+        "(~8%% compression vs ~25%% with tree-sitter). "
+        "Install with: pip install tree-sitter tree-sitter-python"
+    )