diff --git a/backend/internal/bookfile/model.go b/backend/internal/bookfile/model.go
index 8a8cbc47..3cbed21a 100644
--- a/backend/internal/bookfile/model.go
+++ b/backend/internal/bookfile/model.go
@@ -56,7 +56,7 @@ type Book struct {
 	Description string
 	// Notice are the book-level paragraphs a reader sees on OPENING the book — before the first chapter's
 	// title, inside the first spine document (a separate title document would be read by ingest as a
-	// chapter of its own), and at the head of the text file. Empty for a book with nothing to declare.
+	// chapter of its own — before the reader learned to fold an uncovered leading document into chapter one), and at the head of the text file. Empty for a book with nothing to declare.
 	Notice []string
 	// Chapters in reading order; at least one (an EPUB with an empty spine is not an EPUB).
 	Chapters []Chapter
diff --git a/backend/internal/chunk/ingest_test.go b/backend/internal/chunk/ingest_test.go
index 125b2970..50eebd31 100644
--- a/backend/internal/chunk/ingest_test.go
+++ b/backend/internal/chunk/ingest_test.go
@@ -574,7 +574,8 @@ func TestExtractXHTMLRejectsNonUTF8Charset(t *testing.T) {
 
 func TestIngestEPUBPercentEncodedHref(t *testing.T) {
 	// Real epubs percent-encode non-ASCII (and spaced) filenames in the manifest while the zip
-	// entry carries the decoded name. Without resolveHref's url.PathUnescape the entry is missed
+	// entry carries the decoded name. Without the percent-decode in hrefTarget (which resolveHref wraps)
+	// the entry is missed
 	// and ingest fails loud on a chapter that is actually present.
 	chapters := []chunktest.Chapter{
 		{ID: "c1", Href: "%E7%AC%AC%E4%B8%80%E7%AB%A0.xhtml", EntryName: "第一章.xhtml", Body: `<p>第一章。</p>`},
diff --git a/backend/internal/chunk/ingestnotes_test.go b/backend/internal/chunk/ingestnotes_test.go
index f4eb4896..7e2981ce 100644
--- a/backend/internal/chunk/ingestnotes_test.go
+++ b/backend/internal/chunk/ingestnotes_test.go
@@ -19,8 +19,9 @@ func TestEveryIngestCountReachesTheAlarm(t *testing.T) {
 		f := rt.Field(i)
 		d := &Document{Chapters: []string{"x"}}
 		fv := reflect.ValueOf(d).Elem().Field(i)
-		// Every field that carries an alarm, whatever its type. Restricting this to ints is how the guard
-		// would quietly stop covering a count the day one grows into a list.
+		// The field types that carry an alarm TODAY: ints, and the one slice a count grew into. ⚠ This switch
+		// is the guard's OWN limit — a counter of any other type falls into `default` and is skipped silently,
+		// so a new alarm field must be added here as well as to IngestNotes.
 		switch {
 		case f.Type.Kind() == reflect.Int:
 			fv.SetInt(1)