diff --git a/open-sse/services/antigravityProjectPersistence.ts b/open-sse/services/antigravityProjectPersistence.ts
index f34445fe00..1421a8f480 100644
--- a/open-sse/services/antigravityProjectPersistence.ts
+++ b/open-sse/services/antigravityProjectPersistence.ts
@@ -1,9 +1,24 @@
 /**
  * Re-export from `antigravityProjectPersist.ts` plus a connection-preference helper.
+ *
+ * The persistence layer for a runtime-discovered Antigravity projectId lives in
+ * the sibling file `antigravityProjectPersist.ts` (named by its core function).
+ * This module adds `preferAntigravityConnectionsWithStoredProject()`, used by the
+ * quota-strategy engine to give priority to connections whose projectId has
+ * already been discovered and persisted.
  */
+
 import { persistDiscoveredAntigravityProjectId } from "./antigravityProjectPersist.ts";
+
 export { persistDiscoveredAntigravityProjectId };
 
+/**
+ * Return only the Antigravity connections that already have a stored projectId.
+ *
+ * A connection whose projectId has been discovered and persisted can be used
+ * immediately; a connection without one would need to go through the Code Assist
+ * bootstrap first, which is handled by the calling strategy's fallback path.
+ */
 export function preferAntigravityConnectionsWithStoredProject(
   connections: Array<Record<string, unknown>>
 ): Array<Record<string, unknown>> {