diff --git a/.env.example b/.env.example
index a90dded7..5e172630 100644
--- a/.env.example
+++ b/.env.example
@@ -4,7 +4,7 @@ DATABASE_POOL_SIZE=10
 
 # Vector store for workspace memory (optional)
 # When set to "lancedb", uses LanceDB for semantic search instead of pgvector/libsql
-# VECTOR_BACKEND=pgvector   # default: use database's built-in (pgvector or libsql_vector_idx)
+# VECTOR_BACKEND=builtin   # default: use database's built-in index (pgvector or libsql_vector_idx); "pgvector" is also accepted as an alias for "builtin"
 # VECTOR_BACKEND=lancedb
 # LANCEDB_PATH=~/.ironclaw/lancedb   # path for LanceDB when VECTOR_BACKEND=lancedb