diff --git a/tests/test_vendor_capabilities.py b/tests/test_vendor_capabilities.py
new file mode 100644
index 00000000..8e1516a3
--- /dev/null
+++ b/tests/test_vendor_capabilities.py
@@ -0,0 +1,40 @@
+import pytest
+from src.vendor_capabilities import VendorCapabilities, get_capabilities, register
+
+@pytest.fixture(autouse=True)
+def _clean_registry():
+ import src.vendor_capabilities
+ snapshot = src.vendor_capabilities._REGISTRY.copy()
+ yield
+ src.vendor_capabilities._REGISTRY.clear()
+ src.vendor_capabilities._REGISTRY.update(snapshot)
+
+def test_registry_lookup_known_model():
+ caps = VendorCapabilities(
+  vendor='qwen',
+  model='qwen-max',
+  vision=False,
+  context_window=32768
+ )
+ register(caps)
+ retrieved = get_capabilities('qwen', 'qwen-max')
+ assert retrieved.vendor == 'qwen'
+ assert retrieved.model == 'qwen-max'
+ assert retrieved.context_window == 32768
+ assert retrieved.vision is False
+
+def test_fallback_to_vendor_default():
+ caps = VendorCapabilities(
+  vendor='llama',
+  model='*',
+  context_window=131072,
+  cost_tracking=False
+ )
+ register(caps)
+ retrieved = get_capabilities('llama', 'llama-3.3-70b-specdec')
+ assert retrieved.context_window == 131072
+ assert retrieved.cost_tracking is False
+
+def test_unknown_vendor_raises():
+ with pytest.raises(KeyError, match='No capabilities registered'):
+  get_capabilities('nonexistent_vendor', 'anymodel')