diff --git a/chat_test.go b/chat_test.go
index 294d2f4..95558f9 100644
--- a/chat_test.go
+++ b/chat_test.go
@@ -217,3 +217,43 @@ func TestAddToolContent(t *testing.T) {
 		})
 	}
 }
+
+func TestAddToolContentError(t *testing.T) {
+	chat := &aichat.Chat{}
+	
+	// Create a struct that will fail JSON marshaling
+	badContent := make(chan int)
+	
+	err := chat.AddToolContent("test", "test-id", badContent)
+	if err == nil {
+		t.Error("Expected error when marshaling invalid content, got nil")
+	}
+}
+
+func TestUnmarshalJSONError(t *testing.T) {
+	chat := &aichat.Chat{}
+	
+	// Invalid JSON that will cause an unmarshal error
+	invalidJSON := []byte(`{"messages": [{"role": "user", "content": invalid}]}`)
+	
+	err := chat.UnmarshalJSON(invalidJSON)
+	if err == nil {
+		t.Error("Expected error when unmarshaling invalid JSON, got nil")
+	}
+}
+
+func TestContentPartsError(t *testing.T) {
+	msg := &aichat.Message{
+		Role: "user",
+		// Content that will fail JSON marshaling
+		Content: []interface{}{make(chan int)},
+	}
+	
+	parts, err := msg.ContentParts()
+	if err == nil {
+		t.Error("Expected error when processing invalid content parts, got nil")
+	}
+	if parts != nil {
+		t.Error("Expected nil parts when error occurs")
+	}
+}
diff --git a/storage.go b/storage.go
index 3f7fe98..5586b7d 100644
--- a/storage.go
+++ b/storage.go
@@ -31,7 +31,7 @@ func (chat *Chat) Load(ctx context.Context, key string) error {
 	defer reader.Close()
 
 	if err := json.NewDecoder(reader).Decode(chat); err != nil {
-		return fmt.Errorf("failed to decode session: %v", err)
+		return fmt.Errorf("failed to decode chat data: %v", err)
 	}
 
 	return nil
@@ -45,7 +45,7 @@ func (chat *Chat) Save(ctx context.Context, key string) error {
 
 	data, err := json.Marshal(chat)
 	if err != nil {
-		return fmt.Errorf("failed to marshal session: %v", err)
+		return fmt.Errorf("failed to marshal chat data: %v", err)
 	}
 
 	return chat.Options.S3.Put(ctx, key, bytes.NewReader(data))
diff --git a/storage_test.go b/storage_test.go
index a07791e..0c8ec9e 100644
--- a/storage_test.go
+++ b/storage_test.go
@@ -3,6 +3,7 @@ package aichat_test
 import (
 	"context"
 	"errors"
+	"fmt"
 	"io"
 	"strings"
 	"testing"
@@ -43,6 +44,23 @@ func (m *mockS3) Delete(ctx context.Context, key string) error {
 	return nil
 }
 
+// mockS3WithErrors is a mock S3 implementation that returns errors
+type mockS3WithErrors struct {
+	mockS3
+	shouldErrorOnGet bool
+	returnInvalidJSON bool
+}
+
+func (m *mockS3WithErrors) Get(ctx context.Context, key string) (io.ReadCloser, error) {
+	if m.shouldErrorOnGet {
+		return nil, fmt.Errorf("mock get error")
+	}
+	if m.returnInvalidJSON {
+		return io.NopCloser(strings.NewReader("invalid json")), nil
+	}
+	return m.mockS3.Get(ctx, key)
+}
+
 func TestChatStorage(t *testing.T) {
 	ctx := context.Background()
 	s3 := newMockS3()
@@ -98,6 +116,53 @@ func TestStorageErrors(t *testing.T) {
 	if err := session.Load(ctx, "test-key"); err == nil {
 		t.Error("Expected error when loading with nil S3")
 	}
+
+	t.Run("get error", func(t *testing.T) {
+		s3 := &mockS3WithErrors{shouldErrorOnGet: true}
+		chat := &aichat.Chat{Options: aichat.Options{S3: s3}}
+		
+		err := chat.Load(ctx, "test-key")
+		if err == nil {
+			t.Error("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "failed to get session from storage") {
+			t.Errorf("unexpected error message: %v", err)
+		}
+	})
+
+	t.Run("decode error", func(t *testing.T) {
+		s3 := &mockS3WithErrors{returnInvalidJSON: true}
+		chat := &aichat.Chat{Options: aichat.Options{S3: s3}}
+		
+		err := chat.Load(ctx, "test-key")
+		if err == nil {
+			t.Error("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "failed to decode chat data") {
+			t.Errorf("unexpected error message: %v", err)
+		}
+	})
+
+	t.Run("marshal error", func(t *testing.T) {
+		s3 := newMockS3()
+		chat := &aichat.Chat{
+			Options: aichat.Options{S3: s3},
+			Messages: []aichat.Message{
+				{
+					Role: "user",
+					Content: make(chan int), // channels cannot be marshaled to JSON
+				},
+			},
+		}
+
+		err := chat.Save(ctx, "test-key")
+		if err == nil {
+			t.Error("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "failed to marshal chat data") {
+			t.Errorf("unexpected error message: %v", err)
+		}
+	})
 }
 
 func TestNewStorage(t *testing.T) {