diff --git a/.gitleaksignore b/.gitleaksignore
index c2ff053a..0e1589c2 100644
--- a/.gitleaksignore
+++ b/.gitleaksignore
@@ -5,3 +5,10 @@
 b2dccbe6d37e74e98b8a57593c1a5bb4994fba59:mcp_agent.secrets.yaml:generic-api-key:9
 420d07580e83885cdf784115131aea884e704a8f:mcp_agent.secrets.yaml:generic-api-key:2
 225e344437173185f22f30cbac58fc82f9fbe3ed:mcp_agent.secrets.yaml:generic-api-key:2
+
+# Test fixture, not a credential: the literal "sk-secret123456" inside a
+# RuntimeError message, used to assert that error text is redacted before it
+# reaches the UI. It arrived with the #131 merge, which recorded the branch in
+# history without applying its tree — so the file does not exist on main and
+# the finding cannot be fixed by editing it.
+6421db9a2fb04589200f8883f950a329b7ced1cd:tests/ui_session_resume_test.py:generic-api-key:87