diff --git a/.claude/rules/session-protocol.md b/.claude/rules/session-protocol.md
index 616dffa..ad70243 100644
--- a/.claude/rules/session-protocol.md
+++ b/.claude/rules/session-protocol.md
@@ -24,7 +24,7 @@ With MCP tools:
 ```
 get_messages(to_agent="state-hub", unread_only=True)
 ```
-Mark read with `mark_message_read(message_id)`. Reply or act on coordination
+Mark read with `mark_message_read(message_id, reader="state-hub")`. Reply or act on coordination
 requests before proceeding.
 
 Without MCP tools: