diff --git a/tests/run_agent/test_concurrent_interrupt.py b/tests/run_agent/test_concurrent_interrupt.py
index 9a6ba73e..61d7752f 100644
--- a/tests/run_agent/test_concurrent_interrupt.py
+++ b/tests/run_agent/test_concurrent_interrupt.py
@@ -20,6 +20,7 @@ def _make_agent(monkeypatch):
     monkeypatch.setenv("HERMES_INFERENCE_PROVIDER", "")
     # Avoid full AIAgent init — just import the class and build a stub
     import run_agent as _ra
+    from agent.tool_guardrails import ToolCallGuardrailController
 
     class _Stub:
         _interrupt_requested = False
@@ -53,6 +54,12 @@ def _make_agent(monkeypatch):
             self._tool_worker_threads: set = set()
             self._tool_worker_threads_lock = threading.Lock()
             self._active_children_lock = threading.Lock()
+            # Mirror AIAgent.__init__ (run_agent.py:1160 — added in 58b89965
+            # "fix(agent): add tool-call loop guardrails", 2026-04-27).
+            # _execute_tool_calls_concurrent calls self._tool_guardrails
+            # .before_call(...) on every tool, so the stub needs a real
+            # controller instance with default (warning-only) config.
+            self._tool_guardrails = ToolCallGuardrailController()
 
         def _touch_activity(self, desc):
             self._last_activity = time.time()
@@ -77,6 +84,14 @@ def _make_agent(monkeypatch):
     stub._execute_tool_calls_concurrent = _ra.AIAgent._execute_tool_calls_concurrent.__get__(stub)
     stub.interrupt = _ra.AIAgent.interrupt.__get__(stub)
     stub.clear_interrupt = _ra.AIAgent.clear_interrupt.__get__(stub)
+    # Tool-loop guardrails (added in 58b89965, 2026-04-27) are invoked
+    # before/after every concurrent tool. Bind the real helpers — the
+    # default ToolCallGuardrailController() above is warning-only so
+    # they never block a tool, just observe.
+    stub._append_guardrail_observation = _ra.AIAgent._append_guardrail_observation.__get__(stub)
+    stub._guardrail_block_result = _ra.AIAgent._guardrail_block_result.__get__(stub)
+    stub._set_tool_guardrail_halt = lambda *a, **kw: None
+    stub._tool_guardrail_halt_decision = None
     # /steer injection (added in PR #12116) fires after every concurrent
     # tool batch. Stub it as a no-op — this test exercises interrupt
     # fanout, not steer injection.
@@ -107,7 +122,9 @@ def test_concurrent_interrupt_cancels_pending(monkeypatch):
 
     original_invoke = agent._invoke_tool
 
-    def slow_tool(name, args, task_id, call_id=None):
+    def slow_tool(name, args, task_id, call_id=None, **kwargs):
+        # **kwargs swallows production-only kwargs (messages,
+        # pre_tool_block_checked) added to _invoke_tool over time.
         if name == "slow_one":
             # Block until the test sets the interrupt
             barrier.wait(timeout=10)
@@ -184,7 +201,9 @@ def test_running_concurrent_worker_sees_is_interrupted(monkeypatch):
     observed = {"saw_true": False, "poll_count": 0, "worker_tid": None}
     worker_started = threading.Event()
 
-    def polling_tool(name, args, task_id, call_id=None, messages=None):
+    def polling_tool(name, args, task_id, call_id=None, messages=None, **kwargs):
+        # **kwargs swallows production-only kwargs (pre_tool_block_checked)
+        # added to _invoke_tool over time.
         observed["worker_tid"] = threading.current_thread().ident
         worker_started.set()
         deadline = time.monotonic() + 5.0