diff --git a/internal/playback/handler/hls_playlist.go b/internal/playback/handler/hls_playlist.go
index 5af280f..23b6916 100644
--- a/internal/playback/handler/hls_playlist.go
+++ b/internal/playback/handler/hls_playlist.go
@@ -1,6 +1,7 @@
 package handler
 
 import (
+	"fmt"
 	"net/http"
 	"net/url"
 	"strings"
@@ -22,7 +23,7 @@ func isHLSPlaylistResponse(targetURL string, headers http.Header) bool {
 func (h *PlaybackHandler) rewriteHLSPlaylist(body string, playlistURL string, referer string) (string, error) {
 	baseURL, err := url.Parse(playlistURL)
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("parse playlist url %q: %w", playlistURL, err)
 	}
 
 	lines := strings.SplitAfter(body, "\n")
@@ -47,7 +48,7 @@ func (h *PlaybackHandler) rewriteHLSPlaylist(body string, playlistURL string, re
 				rewritten, err = h.proxyPlaylistURI(trimmed, baseURL, referer)
 			}
 			if err != nil {
-				return "", err
+				return "", fmt.Errorf("rewrite hls playlist line %q: %w", trimmed, err)
 			}
 		}
 		out.WriteString(rewritten)
@@ -76,7 +77,7 @@ func (h *PlaybackHandler) rewriteHLSQuotedURIs(line string, baseURL *url.URL, re
 		}
 		proxied, err := h.proxyPlaylistURI(remaining[:end], baseURL, referer)
 		if err != nil {
-			return "", err
+			return "", fmt.Errorf("rewrite quoted hls uri %q: %w", remaining[:end], err)
 		}
 		out.WriteString(proxied)
 		remaining = remaining[end:]
@@ -86,11 +87,11 @@ func (h *PlaybackHandler) rewriteHLSQuotedURIs(line string, baseURL *url.URL, re
 func (h *PlaybackHandler) proxyPlaylistURI(rawURI string, baseURL *url.URL, referer string) (string, error) {
 	target, err := baseURL.Parse(rawURI)
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("parse hls uri %q: %w", rawURI, err)
 	}
 	token, err := h.svc.SignProxyToken(target.String(), referer, "stream")
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("sign hls proxy token for %q: %w", target.String(), err)
 	}
 	params := url.Values{}
 	params.Set("token", token)
diff --git a/internal/playback/handler/proxy_request.go b/internal/playback/handler/proxy_request.go
index ad81268..871f021 100644
--- a/internal/playback/handler/proxy_request.go
+++ b/internal/playback/handler/proxy_request.go
@@ -2,6 +2,7 @@ package handler
 
 import (
 	"context"
+	"fmt"
 	netutil "mal/pkg/net"
 	"net/http"
 )
@@ -9,7 +10,7 @@ import (
 func newProxyRequest(ctx context.Context, targetURL string, referer string) (*http.Request, error) {
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, targetURL, nil)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("build proxy request for %q: %w", targetURL, err)
 	}
 
 	if referer != "" {
diff --git a/internal/playback/progress.go b/internal/playback/progress.go
index cd35ad0..6494bb9 100644
--- a/internal/playback/progress.go
+++ b/internal/playback/progress.go
@@ -82,13 +82,13 @@ func (s *playbackService) CompleteAnime(ctx context.Context, userID string, anim
 				CurrentTimeSeconds: entry.CurrentTimeSeconds,
 			})
 			if err != nil {
-				return err
+				return fmt.Errorf("upsert completed watchlist entry user_id=%s anime_id=%d: %w", userID, animeID, err)
 			}
 		}
 
 		return nil
 	}); err != nil {
-		return err
+		return fmt.Errorf("complete anime transaction user_id=%s anime_id=%d: %w", userID, animeID, err)
 	}
 
 	if err := s.auditSvc.Record(ctx, domain.AuditEvent{
@@ -112,7 +112,7 @@ func (s *playbackService) SaveProgress(ctx context.Context, userID string, anime
 	err := s.repo.InTx(ctx, func(txCtx context.Context, repo domain.PlaybackRepository) error {
 		if _, err := repo.GetAnime(txCtx, animeID); err != nil {
 			if _, err := repo.UpsertAnime(txCtx, minimalAnimeParams(animeID)); err != nil {
-				return err
+				return fmt.Errorf("upsert minimal anime %d: %w", animeID, err)
 			}
 		}
 
@@ -124,10 +124,13 @@ func (s *playbackService) SaveProgress(ctx context.Context, userID string, anime
 			CurrentTimeSeconds: timeSeconds,
 			DurationSeconds:    sql.NullFloat64{Valid: false},
 		})
-		return err
+		if err != nil {
+			return fmt.Errorf("upsert continue watching entry user_id=%s anime_id=%d episode=%d: %w", userID, animeID, episode, err)
+		}
+		return nil
 	})
 	if err != nil {
-		return err
+		return fmt.Errorf("save progress transaction user_id=%s anime_id=%d episode=%d: %w", userID, animeID, episode, err)
 	}
 
 	event := domain.AuditEvent{
@@ -166,7 +169,10 @@ func (s *playbackService) ensureAnimeRow(ctx context.Context, anime domain.Anime
 		return nil
 	}
 	_, err := s.repo.UpsertAnime(ctx, animeParams(anime))
-	return err
+	if err != nil {
+		return fmt.Errorf("upsert anime %d: %w", anime.MalID, err)
+	}
+	return nil
 }
 
 func animeParams(anime domain.Anime) db.UpsertAnimeParams {
diff --git a/internal/playback/skip_segments.go b/internal/playback/skip_segments.go
index 2cab708..f737a32 100644
--- a/internal/playback/skip_segments.go
+++ b/internal/playback/skip_segments.go
@@ -24,7 +24,7 @@ func normalizeSkipType(skipType string) (string, error) {
 	case "ed", "ending", "outro":
 		return "ed", nil
 	default:
-		return "", fmt.Errorf("invalid skip_type")
+		return "", fmt.Errorf("invalid skip_type %q", skipType)
 	}
 }
 
@@ -33,19 +33,19 @@ func (s *playbackService) UpsertSkipSegmentOverride(ctx context.Context, userID
 		return fmt.Errorf("not authenticated")
 	}
 	if animeID <= 0 || episode <= 0 {
-		return fmt.Errorf("invalid anime/episode")
+		return fmt.Errorf("invalid anime/episode: anime_id=%d episode=%d", animeID, episode)
 	}
 	t, err := normalizeSkipType(skipType)
 	if err != nil {
-		return err
+		return fmt.Errorf("normalize skip type: %w", err)
 	}
 	if !(startTime >= 0) || !(endTime > startTime) {
-		return fmt.Errorf("invalid interval")
+		return fmt.Errorf("invalid interval: start=%f end=%f", startTime, endTime)
 	}
 	if endTime-startTime < 5 || endTime-startTime > 10*60 {
-		return fmt.Errorf("interval duration out of range")
+		return fmt.Errorf("interval duration out of range: duration=%f", endTime-startTime)
 	}
-	return s.repo.UpsertSkipSegmentOverride(ctx, db.SkipSegmentOverrideRow{
+	if err := s.repo.UpsertSkipSegmentOverride(ctx, db.SkipSegmentOverrideRow{
 		ID:        uuid.New().String(),
 		UserID:    userID,
 		AnimeID:   animeID,
@@ -53,7 +53,10 @@ func (s *playbackService) UpsertSkipSegmentOverride(ctx context.Context, userID
 		SkipType:  t,
 		StartTime: startTime,
 		EndTime:   endTime,
-	})
+	}); err != nil {
+		return fmt.Errorf("upsert skip segment override: %w", err)
+	}
+	return nil
 }
 
 func (s *playbackService) fetchSkipSegments(ctx context.Context, userID string, malID int, episode string) ([]domain.SkipSegment, error) {