diff --git a/codex-rs/app-server-protocol/src/protocol/v2.rs b/codex-rs/app-server-protocol/src/protocol/v2.rs
index 7a360cee20..85ce73ab3f 100644
--- a/codex-rs/app-server-protocol/src/protocol/v2.rs
+++ b/codex-rs/app-server-protocol/src/protocol/v2.rs
@@ -227,6 +227,8 @@ pub enum ConfigLayerSource {
     #[serde(rename_all = "camelCase")]
     #[ts(rename_all = "camelCase")]
     System {
+        /// This is the path to the system config.toml file, though it is not
+        /// guaranteed to exist.
         file: AbsolutePathBuf,
     },