fix(delegate): strip skills toolset from leaf subagents

tests/tools/test_delegate.py

@@ -145,7 +145,7 @@ def test_empty_context_ignored(self):
 
 class TestStripBlockedTools(unittest.TestCase):
     def test_removes_blocked_toolsets(self):
-        result = _strip_blocked_tools(["terminal", "file", "delegation", "clarify", "memory", "code_execution"])
+        result = _strip_blocked_tools(["terminal", "file", "delegation", "clarify", "memory", "code_execution", "skills"])
         self.assertEqual(sorted(result), ["file", "terminal"])
 
     def test_preserves_allowed_toolsets(self):

tests/tools/test_delegate_toolset_scope.py

@@ -46,12 +46,13 @@ def test_no_toolsets_requested_inherits_parent(self):
         assert "file" in child
         assert "web" in child
 
-    def test_strip_blocked_removes_delegation(self):
-        """Blocked toolsets (delegation, clarify, etc.) are always removed."""
-        child = _strip_blocked_tools(["terminal", "delegation", "clarify", "memory"])
+    def test_strip_blocked_removes_blocked(self):
+        """Blocked toolsets (delegation, clarify, memory, skills) are always removed."""
+        child = _strip_blocked_tools(["terminal", "delegation", "clarify", "memory", "skills"])
         assert "delegation" not in child
         assert "clarify" not in child
         assert "memory" not in child
+        assert "skills" not in child
         assert "terminal" in child
 
     def test_empty_intersection_yields_empty_toolsets(self):

tools/delegate_tool.py

@@ -710,6 +710,7 @@ def _strip_blocked_tools(toolsets: List[str]) -> List[str]:
         "clarify",
         "memory",
         "code_execution",
+        "skills",
     }
     return [t for t in toolsets if t not in blocked_toolset_names]