diff --git a/src/esdl4tulipa/parser.py b/src/esdl4tulipa/parser.py
index 604c1b6..ea5a159 100644
--- a/src/esdl4tulipa/parser.py
+++ b/src/esdl4tulipa/parser.py
@@ -60,9 +60,11 @@ def kinds(*assets: esdl.EnergyAsset, unique=True) -> list[str] | set[str]:
             if ks == {"energynetwork", "transport"}:
                 res.append("energynetwork")
             else:
-                raise RuntimeError(f"{a}: unexpected asset type {ks}")
+                raise RuntimeError(f"{a}: ambiguous asset type {ks}")
         else:
             res.extend(ks)
+    if len(res) == 0:
+        raise ValueError(f"{assets}: unknown asset")
     return set(res) if unique else res
 
 
diff --git a/tests/test_parser.py b/tests/test_parser.py
index a73cc3a..623cb16 100644
--- a/tests/test_parser.py
+++ b/tests/test_parser.py
@@ -72,6 +72,11 @@ def test_asset_kinds(edges):
     assert inferred == _kinds
 
 
+def test_unknown_asset_kinds():
+    with pytest.raises(ValueError, match="unknown asset"):
+        kinds(esdl.BuildingUnit())
+
+
 def test_batched():
     seq = [
         esdl.Pipe(),
@@ -159,6 +164,11 @@ def test_edge(empty_edges):
         )
 
 
+def test_edge_error():
+    with pytest.raises(ValueError, match="uncharted territory"):
+        edge(esdl.GasProducer(), esdl.GasNetwork(), esdl.GasNetwork(), esdl.GasDemand())
+
+
 def test_find_edges(edges):
     _, *gns = edges[0]
     _, *expect = edges[1]