diff --git a/samsung_appliance/registry/capability.py b/samsung_appliance/registry/capability.py
new file mode 100644
index 0000000..87c941e
--- /dev/null
+++ b/samsung_appliance/registry/capability.py
@@ -0,0 +1,19 @@
+"""A Capability binds one OCF resource type (rt) to the entities it produces."""
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Callable, Optional
+
+from .entities import SamsungEntityDescription
+
+
+@dataclass(frozen=True, kw_only=True)
+class Capability:
+    rt: str
+    entities: tuple[SamsungEntityDescription, ...]
+    poll_tier: str = 'warm'                  # 'hot' | 'warm' | 'cold'
+    observe: bool = True
+    # Rare optional hooks — only operational-state-style resources use these.
+    active_when: Optional[Callable[[dict], bool]] = None
+    on_observation: Optional[Callable[[dict, dict], None]] = None
+    project: Optional[Callable[[dict, dict], dict]] = None
diff --git a/tests/test_capability.py b/tests/test_capability.py
new file mode 100644
index 0000000..9cc5b3c
--- /dev/null
+++ b/tests/test_capability.py
@@ -0,0 +1,20 @@
+from samsung_appliance.registry.capability import Capability
+from samsung_appliance.registry.entities import BinarySensorDesc
+
+
+def test_capability_defaults():
+    c = Capability(rt='x.com.samsung.da.kidsLock',
+                   entities=(BinarySensorDesc(key='child_lock', field='x.com.samsung.da.kidsLock'),))
+    assert c.poll_tier == 'warm'
+    assert c.observe is True
+    assert c.active_when is None
+    assert len(c.entities) == 1
+
+
+def test_capability_is_frozen():
+    c = Capability(rt='x', entities=())
+    try:
+        c.rt = 'y'
+    except Exception:
+        return
+    raise AssertionError("expected frozen dataclass")