diff --git a/internal/handlers/auth.go b/internal/handlers/auth.go
index 0a702213..ce929b4e 100644
--- a/internal/handlers/auth.go
+++ b/internal/handlers/auth.go
@@ -124,8 +124,10 @@ type UserProfile struct {
 	Role      string `json:"role"`
 	Theme     string `json:"theme,omitempty"`
 	// User-level default audiobook playback speed (plan §8); 0 omits.
-	DefaultAudioSpeed float64 `json:"default_audio_speed,omitempty"`
-	// Whether the web reader/player should hold a Screen Wake Lock.
+	// Response-only struct: omit nothing — default_audio_speed is NOT NULL
+	// DEFAULT 1.0 (writes validate 0.25–4), so a real profile always emits
+	// it; omitempty here would drop a contract field from the docs gate.
+	DefaultAudioSpeed float64 `json:"default_audio_speed"`	// Whether the web reader/player should hold a Screen Wake Lock.
 	KeepScreenAwake bool `json:"keep_screen_awake"`
 	// Resume rewind: seconds before the saved position the audio
 	// player starts (open-resume and every genuine unpause). 0 is a