diff --git a/src/agents/pi-embedded-runner/google.ts b/src/agents/pi-embedded-runner/google.ts
index 04ee11620..8158c2c83 100644
--- a/src/agents/pi-embedded-runner/google.ts
+++ b/src/agents/pi-embedded-runner/google.ts
@@ -250,6 +250,7 @@ export async function sanitizeSessionHistory(params: {
   sessionId: string;
   policy?: TranscriptPolicy;
 }): Promise<AgentMessage[]> {
+  // Keep docs/reference/transcript-hygiene.md in sync with any logic changes here.
   const policy =
     params.policy ??
     resolveTranscriptPolicy({