diff --git a/handlers/generate.go b/handlers/generate.go
index da2b29c..9c30e4f 100644
--- a/handlers/generate.go
+++ b/handlers/generate.go
@@ -58,7 +58,10 @@ func (h *GenerateHandler) Generate(c *gin.Context) {
 	}
 
 	sendEvent := func(event string, data interface{}) {
-		jsonData, _ := json.Marshal(data)
+		jsonData, err := json.Marshal(data)
+		if err != nil {
+			jsonData = []byte(`{"error":"failed to marshal event data"}`)
+		}
 		fmt.Fprintf(c.Writer, "event: %s\ndata: %s\n\n", event, jsonData)
 		flusher.Flush()
 	}
@@ -74,7 +77,14 @@ func (h *GenerateHandler) Generate(c *gin.Context) {
 	}
 
 	// Save analysis to DB
-	resultJSON, _ := json.Marshal(pr)
-	h.db.Exec(`INSERT INTO analyses (repo_id, type, base_ref, head_ref, result) VALUES (?, 'pr_description', ?, ?, ?)`,
-		id, req.Base, req.Head, string(resultJSON))
+	resultJSON, err := json.Marshal(pr)
+	if err != nil {
+		sendEvent("error", map[string]interface{}{"message": "marshal result: " + err.Error()})
+		return
+	}
+	if _, err := h.db.Exec(`INSERT INTO analyses (repo_id, type, base_ref, head_ref, result) VALUES (?, 'pr_description', ?, ?, ?)`,
+		id, req.Base, req.Head, string(resultJSON)); err != nil {
+		sendEvent("error", map[string]interface{}{"message": "save analysis: " + err.Error()})
+		return
+	}
 }
diff --git a/handlers/repos.go b/handlers/repos.go
index 208e53d..2f49675 100644
--- a/handlers/repos.go
+++ b/handlers/repos.go
@@ -43,6 +43,10 @@ func (h *ReposHandler) ListRepos(c *gin.Context) {
 			})
 		}
 	}
+	if err := rows.Err(); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
 	if repos == nil {
 		repos = []gin.H{}
 	}
@@ -61,9 +65,18 @@ func (h *ReposHandler) DeleteRepo(c *gin.Context) {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
 		return
 	}
-	os.RemoveAll(localPath)
-	h.db.Exec(`DELETE FROM analyses WHERE repo_id = ?`, id)
-	h.db.Exec(`DELETE FROM repositories WHERE id = ?`, id)
+	if err := os.RemoveAll(localPath); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "remove repo dir: " + err.Error()})
+		return
+	}
+	if _, err := h.db.Exec(`DELETE FROM analyses WHERE repo_id = ?`, id); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "delete analyses: " + err.Error()})
+		return
+	}
+	if _, err := h.db.Exec(`DELETE FROM repositories WHERE id = ?`, id); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "delete repository: " + err.Error()})
+		return
+	}
 	c.JSON(http.StatusOK, gin.H{"ok": true})
 }
 
@@ -80,17 +93,33 @@ func (h *ReposHandler) CleanupRepos(c *gin.Context) {
 	}
 	defer rows.Close()
 	var cleaned []int64
+	var errs []string
 	for rows.Next() {
 		var id int64
 		var localPath string
 		if rows.Scan(&id, &localPath) == nil {
-			os.RemoveAll(localPath)
-			h.db.Exec(`DELETE FROM analyses WHERE repo_id = ?`, id)
-			h.db.Exec(`DELETE FROM repositories WHERE id = ?`, id)
+			if err := os.RemoveAll(localPath); err != nil {
+				errs = append(errs, fmt.Sprintf("remove %d: %s", id, err.Error()))
+				continue
+			}
+			if _, err := h.db.Exec(`DELETE FROM analyses WHERE repo_id = ?`, id); err != nil {
+				errs = append(errs, fmt.Sprintf("delete analyses %d: %s", id, err.Error()))
+			}
+			if _, err := h.db.Exec(`DELETE FROM repositories WHERE id = ?`, id); err != nil {
+				errs = append(errs, fmt.Sprintf("delete repo %d: %s", id, err.Error()))
+			}
 			cleaned = append(cleaned, id)
 		}
 	}
-	c.JSON(http.StatusOK, gin.H{"cleaned": cleaned})
+	if err := rows.Err(); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	result := gin.H{"cleaned": cleaned}
+	if len(errs) > 0 {
+		result["errors"] = errs
+	}
+	c.JSON(http.StatusOK, result)
 }
 
 // CloneRepo handles POST /api/repos with SSE progress events.
@@ -119,7 +148,10 @@ func (h *ReposHandler) CloneRepo(c *gin.Context) {
 	}
 
 	sendEvent := func(event string, data interface{}) {
-		jsonData, _ := json.Marshal(data)
+		jsonData, err := json.Marshal(data)
+		if err != nil {
+			jsonData = []byte(`{"error":"failed to marshal event data"}`)
+		}
 		fmt.Fprintf(c.Writer, "event: %s\ndata: %s\n\n", event, jsonData)
 		flusher.Flush()
 	}
@@ -155,7 +187,11 @@ func (h *ReposHandler) CloneRepo(c *gin.Context) {
 		sendEvent("error", map[string]interface{}{"message": "save to db: " + err.Error()})
 		return
 	}
-	repoID, _ := res.LastInsertId()
+	repoID, err := res.LastInsertId()
+	if err != nil {
+		sendEvent("error", map[string]interface{}{"message": "get repo id: " + err.Error()})
+		return
+	}
 
 	sendEvent("complete", map[string]interface{}{
 		"repo_id":    repoID,
diff --git a/handlers/review.go b/handlers/review.go
index 8c1a602..157403f 100644
--- a/handlers/review.go
+++ b/handlers/review.go
@@ -90,7 +90,10 @@ func (h *ReviewHandler) Review(c *gin.Context) {
 	}
 
 	sendEvent := func(event string, data interface{}) {
-		jsonData, _ := json.Marshal(data)
+		jsonData, err := json.Marshal(data)
+		if err != nil {
+			jsonData = []byte(`{"error":"failed to marshal event data"}`)
+		}
 		fmt.Fprintf(c.Writer, "event: %s\ndata: %s\n\n", event, jsonData)
 		flusher.Flush()
 	}
@@ -106,15 +109,25 @@ func (h *ReviewHandler) Review(c *gin.Context) {
 	}
 
 	// Save analysis to DB with full review result
-	resultJSON, _ := json.Marshal(reviewResult)
+	resultJSON, err := json.Marshal(reviewResult)
+	if err != nil {
+		sendEvent("error", map[string]interface{}{"message": "marshal result: " + err.Error()})
+		return
+	}
 	res, err := h.db.Exec(`INSERT INTO analyses (repo_id, type, base_ref, head_ref, result) VALUES (?, 'code_review', ?, ?, ?)`,
 		id, req.Base, req.Head, string(resultJSON))
-	if err == nil {
-		analysisID, _ := res.LastInsertId()
-		sendEvent("analysis_saved", map[string]interface{}{
-			"analysis_id": analysisID,
-		})
+	if err != nil {
+		sendEvent("error", map[string]interface{}{"message": "save analysis: " + err.Error()})
+		return
 	}
+	analysisID, err := res.LastInsertId()
+	if err != nil {
+		sendEvent("error", map[string]interface{}{"message": "get analysis id: " + err.Error()})
+		return
+	}
+	sendEvent("analysis_saved", map[string]interface{}{
+		"analysis_id": analysisID,
+	})
 }
 
 // SaveNotes handles POST /api/repos/:id/review/notes — upsert a review note.
@@ -202,6 +215,10 @@ func (h *ReviewHandler) ListReviews(c *gin.Context) {
 			"created_at": createdAt,
 		})
 	}
+	if err := rows.Err(); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
 
 	if analyses == nil {
 		analyses = []map[string]interface{}{}
@@ -305,7 +322,11 @@ func (h *ReviewHandler) GeneratePDF(c *gin.Context) {
 	}
 
 	// Return PDF as download
-	filename := fmt.Sprintf("pr-helper-review-%s.pdf", createdAt[:10])
+	dateStr := createdAt
+	if len(dateStr) > 10 {
+		dateStr = dateStr[:10]
+	}
+	filename := fmt.Sprintf("pr-helper-review-%s.pdf", dateStr)
 	c.Header("Content-Type", "application/pdf")
 	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
 	c.Data(http.StatusOK, "application/pdf", pdfBytes)