diff --git a/cli/cmd/publish.go b/cli/cmd/publish.go
index 5a2b266..e522438 100644
--- a/cli/cmd/publish.go
+++ b/cli/cmd/publish.go
@@ -69,12 +69,22 @@ func publishBookRecords(session atproto.Session, books []store.Book, storePath s
 
 	var failed []string
 
+	// TODO:
+	// call ListBookRecords and build an index:
+	// existing, err := atproto.ListBookRecords(session)
+	//
+	// then, build a map[string]book of olWorkId and isbn13 values already on the pds
+
 	// **Loop over unpublished books** — for each, build a `BookRecord` from the store book (`OLWorkID`, `ISBN` → `ISBN13`, `DateAdded` → `CreatedAt`)
 	for i, book := range books {
 		if book.ATURI != "" {
 			continue
 		}
 
+		// TODO: add a guard for book already indexed
+		// if existingIndex[book.OLWorkID] || existingIndex[book.ISBN] {continue}
+	}
+
 		record := atproto.BookRecord{
 			OLWorkID:  book.OLWorkID,
 			ISBN13:    book.ISBN,
diff --git a/cli/internal/atproto/records.go b/cli/internal/atproto/records.go
index e8ac20b..6b2e429 100644
--- a/cli/internal/atproto/records.go
+++ b/cli/internal/atproto/records.go
@@ -7,6 +7,20 @@ import (
 	"net/http"
 )
 
+// TODO:
+//	type ListRecordsResponse struct {
+//	    Records []struct {
+//	        URI    string      `json:"uri"`
+//	        CID    string      `json:"cid"`
+//	        Value  BookRecord  `json:"value"`
+//	    } `json:"records"`
+//	    Cursor string `json:"cursor"`
+//	}
+//
+// TODO:
+// function to fetch existing book records from PDS, paginated via cursor
+// func ListBookRecords(session Session) (ListRecordsResponse, error)
+
 type BookRecord struct {
 	OLWorkID  string `json:"olWorkId,omitempty"`
 	ISBN13    string `json:"isbn13,omitempty"`