diff --git a/tests/tools/test_delegate_toolset_scope.py b/tests/tools/test_delegate_toolset_scope.py
index fd90dc1b5612..ea3f339b84e7 100644
--- a/tests/tools/test_delegate_toolset_scope.py
+++ b/tests/tools/test_delegate_toolset_scope.py
@@ -54,6 +54,32 @@ def test_strip_blocked_removes_delegation(self):
         assert "memory" not in child
         assert "terminal" in child
 
+    def test_strip_blocked_removes_kanban(self):
+        """The kanban toolset must never pass through to a delegated child.
+
+        A child inherits the parent's ``HERMES_KANBAN_TASK`` env, so a child
+        that also held ``kanban_complete`` / ``kanban_block`` would resolve
+        the *parent's* card and could falsely flip it to done with the
+        child's summary (control-surface-bleed / false-done). Children get no
+        card-terminal authority.
+        """
+        child = _strip_blocked_tools(["terminal", "file", "kanban"])
+        assert "kanban" not in child
+        assert "terminal" in child
+        assert "file" in child
+
+    def test_kanban_stripped_even_when_inherited_from_parent(self):
+        """No-toolsets-requested inheritance path must also drop kanban.
+
+        When ``toolsets`` is None the child inherits the parent's full set
+        through ``_strip_blocked_tools`` — the kanban strip has to hold on
+        that path too, not just when the LLM explicitly requests it.
+        """
+        parent_toolsets = ["terminal", "file", "kanban", "web"]
+        child = _strip_blocked_tools(parent_toolsets)
+        assert "kanban" not in child
+        assert sorted(child) == ["file", "terminal", "web"]
+
     def test_empty_intersection_yields_empty_toolsets(self):
         """If parent has no overlap with requested, child gets nothing extra."""
         parent = SimpleNamespace(enabled_toolsets=["terminal"])
diff --git a/tools/delegate_tool.py b/tools/delegate_tool.py
index 893502ec04ff..f33aba6a6478 100644
--- a/tools/delegate_tool.py
+++ b/tools/delegate_tool.py
@@ -769,13 +769,23 @@ def _strip_blocked_tools(toolsets: List[str]) -> List[str]:
     """Remove toolsets that contain only blocked tools.
 
     The strip set is derived from DELEGATE_BLOCKED_TOOLS plus the explicit
-    composite/scenario toolsets (delegation, code_execution) that have no
-    one-to-one tool. This keeps the blocklist and the strip set in lockstep
+    composite/scenario toolsets (delegation, code_execution, kanban) that have
+    no one-to-one tool. This keeps the blocklist and the strip set in lockstep
     so new blocked tools can't silently leak through as toolset names.
+
+    ``kanban`` is stripped unconditionally — even for orchestrator children.
+    A delegated child inherits the parent's ``HERMES_KANBAN_TASK`` env, so a
+    child holding the kanban terminal verbs (``kanban_complete`` /
+    ``kanban_block``) would resolve the *parent's* card and could retire it
+    with the child's summary while the real deliverable was never produced
+    (false-done, control-surface-bleed). Children get no card-terminal
+    authority.
     """
     # Composite toolsets that should never pass through to children, even
     # though their individual tools aren't all in DELEGATE_BLOCKED_TOOLS.
-    _COMPOSITE_BLOCKED_TOOLSETS = frozenset({"delegation", "code_execution"})
+    _COMPOSITE_BLOCKED_TOOLSETS = frozenset(
+        {"delegation", "code_execution", "kanban"}
+    )
     blocked_toolset_names = {
         name
         for name, defn in TOOLSETS.items()