diff --git a/deltatrace/dsl.py b/deltatrace/dsl.py
index 8639c66..fef9abf 100644
--- a/deltatrace/dsl.py
+++ b/deltatrace/dsl.py
@@ -77,10 +77,32 @@ class TraceGraph:
     self.edges.append((src_id, dst_id, tag))
 
   def merkle_root(self) -> str:
+    """Deterministic Merkle root for the trace graph.
+
+    This implementation avoids Python's non-deterministic hash() across
+    runs by serializing each node to a canonical JSON representation using
+    its public fields. The resulting bytestrings are hashed in a Merkle-like
+    reduction to produce a stable root string.
+    """
     import hashlib
+    import json
+
+    def _canonicalize(obj: object) -> Dict[str, object]:
+      # If the node is a dataclass or has __dict__, extract a stable dict
+      if hasattr(obj, "__dict__"):
+        # Ensure all nested attributes are also representable
+        data = getattr(obj, "__dict__")
+        # Deeply serialize to JSON-safe form by iterating keys
+        return {k: v for k, v in data.items()}
+      # Fallback: convert to string representation
+      return {"repr": str(obj)}
+
     items = []
     for n in self.nodes:
-      items.append(str(hash(n)).encode())
+      canon = _canonicalize(n)
+      # Use a stable JSON representation of the node
+      serialized = json.dumps(canon, sort_keys=True, separators=(",", ":"))
+      items.append(serialized.encode())
     if not items:
       return ""
     level = [hashlib.sha256(i).hexdigest() for i in items]
diff --git a/test.sh b/test.sh
old mode 100644
new mode 100755