fix: add recovery hints to loop guard warnings

tests/agent/test_tool_guardrails.py

@@ -160,6 +160,10 @@ def test_same_tool_varying_args_warns_by_default_without_halting():
     assert first.action == "allow"
     assert [second.action, third.action, fourth.action] == ["warn", "warn", "warn"]
     assert {second.code, third.code, fourth.code} == {"same_tool_failure_warning"}
+    assert "Do not switch to text-only replies" in second.message
+    assert "keep using tools" in second.message
+    assert "diagnose before retrying" in second.message
+    assert "different tool" in second.message
     assert controller.halt_decision is None