feat: document optional replaces for CRUD mutation binding

tests/test_actions_manifest.py

@@ -190,7 +190,21 @@ class TestActionsManifest(unittest.TestCase):
 
             placements = action.get("placements")
             self.assertIsInstance(placements, list, msg=f"{action_id} placements must be array")
-            self.assertGreater(len(placements), 0, msg=f"{action_id} placements empty")
+            replaces = action.get("replaces")
+            if replaces is not None:
+                self.assertIn(
+                    replaces,
+                    {"create", "update", "delete"},
+                    msg=f"{action_id} invalid replaces {replaces!r}",
+                )
+                bind = action.get("bind") or {}
+                tables = bind.get("tables") or []
+                self.assertTrue(
+                    isinstance(tables, list) and len(tables) > 0,
+                    msg=f"{action_id} replaces requires non-empty bind.tables",
+                )
+            else:
+                self.assertGreater(len(placements), 0, msg=f"{action_id} placements empty")
             for placement in placements:
                 self.assertIn(placement, _ALLOWED_PLACEMENTS, msg=f"{action_id} invalid placement {placement!r}")
 
@@ -228,12 +242,18 @@ class TestActionsManifest(unittest.TestCase):
         self.assertIn("interactionByPlacement", props)
         by_placement = props["interactionByPlacement"]
         self.assertIs(by_placement.get("additionalProperties"), False)
-        for key in ("toolbar", "row", "batch", "cron", "agent", "skill-detail"):
+        for key in ("toolbar", "row", "batch", "cron", "agent", "skill-detail", "create", "update", "delete"):
             self.assertIn(key, by_placement.get("properties") or {})
             self.assertEqual(
                 set((by_placement["properties"][key].get("enum") or [])),
                 {"direct", "confirm", "form"},
             )
+        self.assertIn("replaces", props)
+        self.assertEqual(props["replaces"].get("$ref"), "#/$defs/mutationKind")
+        self.assertEqual(
+            set(schema["$defs"]["mutationKind"].get("enum") or []),
+            {"create", "update", "delete"},
+        )
 
     def test_manifest_validates_against_json_schema(self) -> None:
         try: