feat(db): add upstream_model column to usage_logs

Add nullable VARCHAR(100) column to record the actual model sent to upstream providers when model mapping is applied. NULL means no mapping — the requested model was used as-is. Includes migration, concurrent index for aggregation queries, Ent schema regeneration, and migration README correction (forward-only runner, not goose).
2026-04-03 06:52:13 +08:00 · 2026-03-17 19:25:17 +08:00
parent 045cba78b4
commit 51547fa216
14 changed files with 396 additions and 64 deletions
--- a/backend/ent/migrate/schema.go
+++ b/backend/ent/migrate/schema.go
@@ -716,6 +716,7 @@ var (
 		{Name: "id", Type: field.TypeInt64, Increment: true},
 		{Name: "request_id", Type: field.TypeString, Size: 64},
 		{Name: "model", Type: field.TypeString, Size: 100},
+		{Name: "upstream_model", Type: field.TypeString, Nullable: true, Size: 100},
 		{Name: "input_tokens", Type: field.TypeInt, Default: 0},
 		{Name: "output_tokens", Type: field.TypeInt, Default: 0},
 		{Name: "cache_creation_tokens", Type: field.TypeInt, Default: 0},
@@ -755,31 +756,31 @@ var (
 		ForeignKeys: []*schema.ForeignKey{
 			{
 				Symbol:     "usage_logs_api_keys_usage_logs",
-				Columns:    []*schema.Column{UsageLogsColumns[28]},
+				Columns:    []*schema.Column{UsageLogsColumns[29]},
 				RefColumns: []*schema.Column{APIKeysColumns[0]},
 				OnDelete:   schema.NoAction,
 			},
 			{
 				Symbol:     "usage_logs_accounts_usage_logs",
-				Columns:    []*schema.Column{UsageLogsColumns[29]},
+				Columns:    []*schema.Column{UsageLogsColumns[30]},
 				RefColumns: []*schema.Column{AccountsColumns[0]},
 				OnDelete:   schema.NoAction,
 			},
 			{
 				Symbol:     "usage_logs_groups_usage_logs",
-				Columns:    []*schema.Column{UsageLogsColumns[30]},
+				Columns:    []*schema.Column{UsageLogsColumns[31]},
 				RefColumns: []*schema.Column{GroupsColumns[0]},
 				OnDelete:   schema.SetNull,
 			},
 			{
 				Symbol:     "usage_logs_users_usage_logs",
-				Columns:    []*schema.Column{UsageLogsColumns[31]},
+				Columns:    []*schema.Column{UsageLogsColumns[32]},
 				RefColumns: []*schema.Column{UsersColumns[0]},
 				OnDelete:   schema.NoAction,
 			},
 			{
 				Symbol:     "usage_logs_user_subscriptions_usage_logs",
-				Columns:    []*schema.Column{UsageLogsColumns[32]},
+				Columns:    []*schema.Column{UsageLogsColumns[33]},
 				RefColumns: []*schema.Column{UserSubscriptionsColumns[0]},
 				OnDelete:   schema.SetNull,
 			},
@@ -788,32 +789,32 @@ var (
 			{
 				Name:    "usagelog_user_id",
 				Unique:  false,
-				Columns: []*schema.Column{UsageLogsColumns[31]},
+				Columns: []*schema.Column{UsageLogsColumns[32]},
 			},
 			{
 				Name:    "usagelog_api_key_id",
 				Unique:  false,
-				Columns: []*schema.Column{UsageLogsColumns[28]},
+				Columns: []*schema.Column{UsageLogsColumns[29]},
 			},
 			{
 				Name:    "usagelog_account_id",
 				Unique:  false,
-				Columns: []*schema.Column{UsageLogsColumns[29]},
+				Columns: []*schema.Column{UsageLogsColumns[30]},
 			},
 			{
 				Name:    "usagelog_group_id",
 				Unique:  false,
-				Columns: []*schema.Column{UsageLogsColumns[30]},
+				Columns: []*schema.Column{UsageLogsColumns[31]},
 			},
 			{
 				Name:    "usagelog_subscription_id",
 				Unique:  false,
-				Columns: []*schema.Column{UsageLogsColumns[32]},
+				Columns: []*schema.Column{UsageLogsColumns[33]},
 			},
 			{
 				Name:    "usagelog_created_at",
 				Unique:  false,
-				Columns: []*schema.Column{UsageLogsColumns[27]},
+				Columns: []*schema.Column{UsageLogsColumns[28]},
 			},
 			{
 				Name:    "usagelog_model",
@@ -828,17 +829,17 @@ var (
 			{
 				Name:    "usagelog_user_id_created_at",
 				Unique:  false,
-				Columns: []*schema.Column{UsageLogsColumns[31], UsageLogsColumns[27]},
+				Columns: []*schema.Column{UsageLogsColumns[32], UsageLogsColumns[28]},
 			},
 			{
 				Name:    "usagelog_api_key_id_created_at",
 				Unique:  false,
-				Columns: []*schema.Column{UsageLogsColumns[28], UsageLogsColumns[27]},
+				Columns: []*schema.Column{UsageLogsColumns[29], UsageLogsColumns[28]},
 			},
 			{
 				Name:    "usagelog_group_id_created_at",
 				Unique:  false,
-				Columns: []*schema.Column{UsageLogsColumns[30], UsageLogsColumns[27]},
+				Columns: []*schema.Column{UsageLogsColumns[31], UsageLogsColumns[28]},
 			},
 		},
 	}
--- a/backend/ent/mutation.go
+++ b/backend/ent/mutation.go
@@ -18239,6 +18239,7 @@ type UsageLogMutation struct {
 	id                          *int64
 	request_id                  *string
 	model                       *string
+	upstream_model              *string
 	input_tokens                *int
 	addinput_tokens             *int
 	output_tokens               *int
@@ -18576,6 +18577,55 @@ func (m *UsageLogMutation) ResetModel() {
 	m.model = nil
 }

+// SetUpstreamModel sets the "upstream_model" field.
+func (m *UsageLogMutation) SetUpstreamModel(s string) {
+	m.upstream_model = &s
+}
+
+// UpstreamModel returns the value of the "upstream_model" field in the mutation.
+func (m *UsageLogMutation) UpstreamModel() (r string, exists bool) {
+	v := m.upstream_model
+	if v == nil {
+		return
+	}
+	return *v, true
+}
+
+// OldUpstreamModel returns the old "upstream_model" field's value of the UsageLog entity.
+// If the UsageLog object wasn't provided to the builder, the object is fetched from the database.
+// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
+func (m *UsageLogMutation) OldUpstreamModel(ctx context.Context) (v *string, err error) {
+	if !m.op.Is(OpUpdateOne) {
+		return v, errors.New("OldUpstreamModel is only allowed on UpdateOne operations")
+	}
+	if m.id == nil || m.oldValue == nil {
+		return v, errors.New("OldUpstreamModel requires an ID field in the mutation")
+	}
+	oldValue, err := m.oldValue(ctx)
+	if err != nil {
+		return v, fmt.Errorf("querying old value for OldUpstreamModel: %w", err)
+	}
+	return oldValue.UpstreamModel, nil
+}
+
+// ClearUpstreamModel clears the value of the "upstream_model" field.
+func (m *UsageLogMutation) ClearUpstreamModel() {
+	m.upstream_model = nil
+	m.clearedFields[usagelog.FieldUpstreamModel] = struct{}{}
+}
+
+// UpstreamModelCleared returns if the "upstream_model" field was cleared in this mutation.
+func (m *UsageLogMutation) UpstreamModelCleared() bool {
+	_, ok := m.clearedFields[usagelog.FieldUpstreamModel]
+	return ok
+}
+
+// ResetUpstreamModel resets all changes to the "upstream_model" field.
+func (m *UsageLogMutation) ResetUpstreamModel() {
+	m.upstream_model = nil
+	delete(m.clearedFields, usagelog.FieldUpstreamModel)
+}
+
 // SetGroupID sets the "group_id" field.
 func (m *UsageLogMutation) SetGroupID(i int64) {
 	m.group = &i
@@ -20197,7 +20247,7 @@ func (m *UsageLogMutation) Type() string {
 // order to get all numeric fields that were incremented/decremented, call
 // AddedFields().
 func (m *UsageLogMutation) Fields() []string {
-	fields := make([]string, 0, 32)
+	fields := make([]string, 0, 33)
 	if m.user != nil {
 		fields = append(fields, usagelog.FieldUserID)
 	}
@@ -20213,6 +20263,9 @@ func (m *UsageLogMutation) Fields() []string {
 	if m.model != nil {
 		fields = append(fields, usagelog.FieldModel)
 	}
+	if m.upstream_model != nil {
+		fields = append(fields, usagelog.FieldUpstreamModel)
+	}
 	if m.group != nil {
 		fields = append(fields, usagelog.FieldGroupID)
 	}
@@ -20312,6 +20365,8 @@ func (m *UsageLogMutation) Field(name string) (ent.Value, bool) {
 		return m.RequestID()
 	case usagelog.FieldModel:
 		return m.Model()
+	case usagelog.FieldUpstreamModel:
+		return m.UpstreamModel()
 	case usagelog.FieldGroupID:
 		return m.GroupID()
 	case usagelog.FieldSubscriptionID:
@@ -20385,6 +20440,8 @@ func (m *UsageLogMutation) OldField(ctx context.Context, name string) (ent.Value
 		return m.OldRequestID(ctx)
 	case usagelog.FieldModel:
 		return m.OldModel(ctx)
+	case usagelog.FieldUpstreamModel:
+		return m.OldUpstreamModel(ctx)
 	case usagelog.FieldGroupID:
 		return m.OldGroupID(ctx)
 	case usagelog.FieldSubscriptionID:
@@ -20483,6 +20540,13 @@ func (m *UsageLogMutation) SetField(name string, value ent.Value) error {
 		}
 		m.SetModel(v)
 		return nil
+	case usagelog.FieldUpstreamModel:
+		v, ok := value.(string)
+		if !ok {
+			return fmt.Errorf("unexpected type %T for field %s", value, name)
+		}
+		m.SetUpstreamModel(v)
+		return nil
 	case usagelog.FieldGroupID:
 		v, ok := value.(int64)
 		if !ok {
@@ -20921,6 +20985,9 @@ func (m *UsageLogMutation) AddField(name string, value ent.Value) error {
 // mutation.
 func (m *UsageLogMutation) ClearedFields() []string {
 	var fields []string
+	if m.FieldCleared(usagelog.FieldUpstreamModel) {
+		fields = append(fields, usagelog.FieldUpstreamModel)
+	}
 	if m.FieldCleared(usagelog.FieldGroupID) {
 		fields = append(fields, usagelog.FieldGroupID)
 	}
@@ -20962,6 +21029,9 @@ func (m *UsageLogMutation) FieldCleared(name string) bool {
 // error if the field is not defined in the schema.
 func (m *UsageLogMutation) ClearField(name string) error {
 	switch name {
+	case usagelog.FieldUpstreamModel:
+		m.ClearUpstreamModel()
+		return nil
 	case usagelog.FieldGroupID:
 		m.ClearGroupID()
 		return nil
@@ -21012,6 +21082,9 @@ func (m *UsageLogMutation) ResetField(name string) error {
 	case usagelog.FieldModel:
 		m.ResetModel()
 		return nil
+	case usagelog.FieldUpstreamModel:
+		m.ResetUpstreamModel()
+		return nil
 	case usagelog.FieldGroupID:
 		m.ResetGroupID()
 		return nil
--- a/backend/ent/runtime/runtime.go
+++ b/backend/ent/runtime/runtime.go
@@ -821,92 +821,96 @@ func init() {
 			return nil
 		}
 	}()
+	// usagelogDescUpstreamModel is the schema descriptor for upstream_model field.
+	usagelogDescUpstreamModel := usagelogFields[5].Descriptor()
+	// usagelog.UpstreamModelValidator is a validator for the "upstream_model" field. It is called by the builders before save.
+	usagelog.UpstreamModelValidator = usagelogDescUpstreamModel.Validators[0].(func(string) error)
 	// usagelogDescInputTokens is the schema descriptor for input_tokens field.
-	usagelogDescInputTokens := usagelogFields[7].Descriptor()
+	usagelogDescInputTokens := usagelogFields[8].Descriptor()
 	// usagelog.DefaultInputTokens holds the default value on creation for the input_tokens field.
 	usagelog.DefaultInputTokens = usagelogDescInputTokens.Default.(int)
 	// usagelogDescOutputTokens is the schema descriptor for output_tokens field.
-	usagelogDescOutputTokens := usagelogFields[8].Descriptor()
+	usagelogDescOutputTokens := usagelogFields[9].Descriptor()
 	// usagelog.DefaultOutputTokens holds the default value on creation for the output_tokens field.
 	usagelog.DefaultOutputTokens = usagelogDescOutputTokens.Default.(int)
 	// usagelogDescCacheCreationTokens is the schema descriptor for cache_creation_tokens field.
-	usagelogDescCacheCreationTokens := usagelogFields[9].Descriptor()
+	usagelogDescCacheCreationTokens := usagelogFields[10].Descriptor()
 	// usagelog.DefaultCacheCreationTokens holds the default value on creation for the cache_creation_tokens field.
 	usagelog.DefaultCacheCreationTokens = usagelogDescCacheCreationTokens.Default.(int)
 	// usagelogDescCacheReadTokens is the schema descriptor for cache_read_tokens field.
-	usagelogDescCacheReadTokens := usagelogFields[10].Descriptor()
+	usagelogDescCacheReadTokens := usagelogFields[11].Descriptor()
 	// usagelog.DefaultCacheReadTokens holds the default value on creation for the cache_read_tokens field.
 	usagelog.DefaultCacheReadTokens = usagelogDescCacheReadTokens.Default.(int)
 	// usagelogDescCacheCreation5mTokens is the schema descriptor for cache_creation_5m_tokens field.
-	usagelogDescCacheCreation5mTokens := usagelogFields[11].Descriptor()
+	usagelogDescCacheCreation5mTokens := usagelogFields[12].Descriptor()
 	// usagelog.DefaultCacheCreation5mTokens holds the default value on creation for the cache_creation_5m_tokens field.
 	usagelog.DefaultCacheCreation5mTokens = usagelogDescCacheCreation5mTokens.Default.(int)
 	// usagelogDescCacheCreation1hTokens is the schema descriptor for cache_creation_1h_tokens field.
-	usagelogDescCacheCreation1hTokens := usagelogFields[12].Descriptor()
+	usagelogDescCacheCreation1hTokens := usagelogFields[13].Descriptor()
 	// usagelog.DefaultCacheCreation1hTokens holds the default value on creation for the cache_creation_1h_tokens field.
 	usagelog.DefaultCacheCreation1hTokens = usagelogDescCacheCreation1hTokens.Default.(int)
 	// usagelogDescInputCost is the schema descriptor for input_cost field.
-	usagelogDescInputCost := usagelogFields[13].Descriptor()
+	usagelogDescInputCost := usagelogFields[14].Descriptor()
 	// usagelog.DefaultInputCost holds the default value on creation for the input_cost field.
 	usagelog.DefaultInputCost = usagelogDescInputCost.Default.(float64)
 	// usagelogDescOutputCost is the schema descriptor for output_cost field.
-	usagelogDescOutputCost := usagelogFields[14].Descriptor()
+	usagelogDescOutputCost := usagelogFields[15].Descriptor()
 	// usagelog.DefaultOutputCost holds the default value on creation for the output_cost field.
 	usagelog.DefaultOutputCost = usagelogDescOutputCost.Default.(float64)
 	// usagelogDescCacheCreationCost is the schema descriptor for cache_creation_cost field.
-	usagelogDescCacheCreationCost := usagelogFields[15].Descriptor()
+	usagelogDescCacheCreationCost := usagelogFields[16].Descriptor()
 	// usagelog.DefaultCacheCreationCost holds the default value on creation for the cache_creation_cost field.
 	usagelog.DefaultCacheCreationCost = usagelogDescCacheCreationCost.Default.(float64)
 	// usagelogDescCacheReadCost is the schema descriptor for cache_read_cost field.
-	usagelogDescCacheReadCost := usagelogFields[16].Descriptor()
+	usagelogDescCacheReadCost := usagelogFields[17].Descriptor()
 	// usagelog.DefaultCacheReadCost holds the default value on creation for the cache_read_cost field.
 	usagelog.DefaultCacheReadCost = usagelogDescCacheReadCost.Default.(float64)
 	// usagelogDescTotalCost is the schema descriptor for total_cost field.
-	usagelogDescTotalCost := usagelogFields[17].Descriptor()
+	usagelogDescTotalCost := usagelogFields[18].Descriptor()
 	// usagelog.DefaultTotalCost holds the default value on creation for the total_cost field.
 	usagelog.DefaultTotalCost = usagelogDescTotalCost.Default.(float64)
 	// usagelogDescActualCost is the schema descriptor for actual_cost field.
-	usagelogDescActualCost := usagelogFields[18].Descriptor()
+	usagelogDescActualCost := usagelogFields[19].Descriptor()
 	// usagelog.DefaultActualCost holds the default value on creation for the actual_cost field.
 	usagelog.DefaultActualCost = usagelogDescActualCost.Default.(float64)
 	// usagelogDescRateMultiplier is the schema descriptor for rate_multiplier field.
-	usagelogDescRateMultiplier := usagelogFields[19].Descriptor()
+	usagelogDescRateMultiplier := usagelogFields[20].Descriptor()
 	// usagelog.DefaultRateMultiplier holds the default value on creation for the rate_multiplier field.
 	usagelog.DefaultRateMultiplier = usagelogDescRateMultiplier.Default.(float64)
 	// usagelogDescBillingType is the schema descriptor for billing_type field.
-	usagelogDescBillingType := usagelogFields[21].Descriptor()
+	usagelogDescBillingType := usagelogFields[22].Descriptor()
 	// usagelog.DefaultBillingType holds the default value on creation for the billing_type field.
 	usagelog.DefaultBillingType = usagelogDescBillingType.Default.(int8)
 	// usagelogDescStream is the schema descriptor for stream field.
-	usagelogDescStream := usagelogFields[22].Descriptor()
+	usagelogDescStream := usagelogFields[23].Descriptor()
 	// usagelog.DefaultStream holds the default value on creation for the stream field.
 	usagelog.DefaultStream = usagelogDescStream.Default.(bool)
 	// usagelogDescUserAgent is the schema descriptor for user_agent field.
-	usagelogDescUserAgent := usagelogFields[25].Descriptor()
+	usagelogDescUserAgent := usagelogFields[26].Descriptor()
 	// usagelog.UserAgentValidator is a validator for the "user_agent" field. It is called by the builders before save.
 	usagelog.UserAgentValidator = usagelogDescUserAgent.Validators[0].(func(string) error)
 	// usagelogDescIPAddress is the schema descriptor for ip_address field.
-	usagelogDescIPAddress := usagelogFields[26].Descriptor()
+	usagelogDescIPAddress := usagelogFields[27].Descriptor()
 	// usagelog.IPAddressValidator is a validator for the "ip_address" field. It is called by the builders before save.
 	usagelog.IPAddressValidator = usagelogDescIPAddress.Validators[0].(func(string) error)
 	// usagelogDescImageCount is the schema descriptor for image_count field.
-	usagelogDescImageCount := usagelogFields[27].Descriptor()
+	usagelogDescImageCount := usagelogFields[28].Descriptor()
 	// usagelog.DefaultImageCount holds the default value on creation for the image_count field.
 	usagelog.DefaultImageCount = usagelogDescImageCount.Default.(int)
 	// usagelogDescImageSize is the schema descriptor for image_size field.
-	usagelogDescImageSize := usagelogFields[28].Descriptor()
+	usagelogDescImageSize := usagelogFields[29].Descriptor()
 	// usagelog.ImageSizeValidator is a validator for the "image_size" field. It is called by the builders before save.
 	usagelog.ImageSizeValidator = usagelogDescImageSize.Validators[0].(func(string) error)
 	// usagelogDescMediaType is the schema descriptor for media_type field.
-	usagelogDescMediaType := usagelogFields[29].Descriptor()
+	usagelogDescMediaType := usagelogFields[30].Descriptor()
 	// usagelog.MediaTypeValidator is a validator for the "media_type" field. It is called by the builders before save.
 	usagelog.MediaTypeValidator = usagelogDescMediaType.Validators[0].(func(string) error)
 	// usagelogDescCacheTTLOverridden is the schema descriptor for cache_ttl_overridden field.
-	usagelogDescCacheTTLOverridden := usagelogFields[30].Descriptor()
+	usagelogDescCacheTTLOverridden := usagelogFields[31].Descriptor()
 	// usagelog.DefaultCacheTTLOverridden holds the default value on creation for the cache_ttl_overridden field.
 	usagelog.DefaultCacheTTLOverridden = usagelogDescCacheTTLOverridden.Default.(bool)
 	// usagelogDescCreatedAt is the schema descriptor for created_at field.
-	usagelogDescCreatedAt := usagelogFields[31].Descriptor()
+	usagelogDescCreatedAt := usagelogFields[32].Descriptor()
 	// usagelog.DefaultCreatedAt holds the default value on creation for the created_at field.
 	usagelog.DefaultCreatedAt = usagelogDescCreatedAt.Default.(func() time.Time)
 	userMixin := schema.User{}.Mixin()
--- a/backend/ent/schema/usage_log.go
+++ b/backend/ent/schema/usage_log.go
@@ -41,6 +41,12 @@ func (UsageLog) Fields() []ent.Field {
 		field.String("model").
 			MaxLen(100).
 			NotEmpty(),
+		// UpstreamModel stores the actual upstream model name when model mapping
+		// is applied. NULL means no mapping — the requested model was used as-is.
+		field.String("upstream_model").
+			MaxLen(100).
+			Optional().
+			Nillable(),
 		field.Int64("group_id").
 			Optional().
 			Nillable(),
--- a/backend/ent/usagelog.go
+++ b/backend/ent/usagelog.go
@@ -32,6 +32,8 @@ type UsageLog struct {
 	RequestID string `json:"request_id,omitempty"`
 	// Model holds the value of the "model" field.
 	Model string `json:"model,omitempty"`
+	// UpstreamModel holds the value of the "upstream_model" field.
+	UpstreamModel *string `json:"upstream_model,omitempty"`
 	// GroupID holds the value of the "group_id" field.
 	GroupID *int64 `json:"group_id,omitempty"`
 	// SubscriptionID holds the value of the "subscription_id" field.
@@ -175,7 +177,7 @@ func (*UsageLog) scanValues(columns []string) ([]any, error) {
 			values[i] = new(sql.NullFloat64)
 		case usagelog.FieldID, usagelog.FieldUserID, usagelog.FieldAPIKeyID, usagelog.FieldAccountID, usagelog.FieldGroupID, usagelog.FieldSubscriptionID, usagelog.FieldInputTokens, usagelog.FieldOutputTokens, usagelog.FieldCacheCreationTokens, usagelog.FieldCacheReadTokens, usagelog.FieldCacheCreation5mTokens, usagelog.FieldCacheCreation1hTokens, usagelog.FieldBillingType, usagelog.FieldDurationMs, usagelog.FieldFirstTokenMs, usagelog.FieldImageCount:
 			values[i] = new(sql.NullInt64)
-		case usagelog.FieldRequestID, usagelog.FieldModel, usagelog.FieldUserAgent, usagelog.FieldIPAddress, usagelog.FieldImageSize, usagelog.FieldMediaType:
+		case usagelog.FieldRequestID, usagelog.FieldModel, usagelog.FieldUpstreamModel, usagelog.FieldUserAgent, usagelog.FieldIPAddress, usagelog.FieldImageSize, usagelog.FieldMediaType:
 			values[i] = new(sql.NullString)
 		case usagelog.FieldCreatedAt:
 			values[i] = new(sql.NullTime)
@@ -230,6 +232,13 @@ func (_m *UsageLog) assignValues(columns []string, values []any) error {
 			} else if value.Valid {
 				_m.Model = value.String
 			}
+		case usagelog.FieldUpstreamModel:
+			if value, ok := values[i].(*sql.NullString); !ok {
+				return fmt.Errorf("unexpected type %T for field upstream_model", values[i])
+			} else if value.Valid {
+				_m.UpstreamModel = new(string)
+				*_m.UpstreamModel = value.String
+			}
 		case usagelog.FieldGroupID:
 			if value, ok := values[i].(*sql.NullInt64); !ok {
 				return fmt.Errorf("unexpected type %T for field group_id", values[i])
@@ -477,6 +486,11 @@ func (_m *UsageLog) String() string {
 	builder.WriteString("model=")
 	builder.WriteString(_m.Model)
 	builder.WriteString(", ")
+	if v := _m.UpstreamModel; v != nil {
+		builder.WriteString("upstream_model=")
+		builder.WriteString(*v)
+	}
+	builder.WriteString(", ")
 	if v := _m.GroupID; v != nil {
 		builder.WriteString("group_id=")
 		builder.WriteString(fmt.Sprintf("%v", *v))
--- a/backend/ent/usagelog/usagelog.go
+++ b/backend/ent/usagelog/usagelog.go
@@ -24,6 +24,8 @@ const (
 	FieldRequestID = "request_id"
 	// FieldModel holds the string denoting the model field in the database.
 	FieldModel = "model"
+	// FieldUpstreamModel holds the string denoting the upstream_model field in the database.
+	FieldUpstreamModel = "upstream_model"
 	// FieldGroupID holds the string denoting the group_id field in the database.
 	FieldGroupID = "group_id"
 	// FieldSubscriptionID holds the string denoting the subscription_id field in the database.
@@ -135,6 +137,7 @@ var Columns = []string{
 	FieldAccountID,
 	FieldRequestID,
 	FieldModel,
+	FieldUpstreamModel,
 	FieldGroupID,
 	FieldSubscriptionID,
 	FieldInputTokens,
@@ -179,6 +182,8 @@ var (
 	RequestIDValidator func(string) error
 	// ModelValidator is a validator for the "model" field. It is called by the builders before save.
 	ModelValidator func(string) error
+	// UpstreamModelValidator is a validator for the "upstream_model" field. It is called by the builders before save.
+	UpstreamModelValidator func(string) error
 	// DefaultInputTokens holds the default value on creation for the "input_tokens" field.
 	DefaultInputTokens int
 	// DefaultOutputTokens holds the default value on creation for the "output_tokens" field.
@@ -258,6 +263,11 @@ func ByModel(opts ...sql.OrderTermOption) OrderOption {
 	return sql.OrderByField(FieldModel, opts...).ToFunc()
 }

+// ByUpstreamModel orders the results by the upstream_model field.
+func ByUpstreamModel(opts ...sql.OrderTermOption) OrderOption {
+	return sql.OrderByField(FieldUpstreamModel, opts...).ToFunc()
+}
+
 // ByGroupID orders the results by the group_id field.
 func ByGroupID(opts ...sql.OrderTermOption) OrderOption {
 	return sql.OrderByField(FieldGroupID, opts...).ToFunc()
--- a/backend/ent/usagelog/where.go
+++ b/backend/ent/usagelog/where.go
@@ -80,6 +80,11 @@ func Model(v string) predicate.UsageLog {
 	return predicate.UsageLog(sql.FieldEQ(FieldModel, v))
 }

+// UpstreamModel applies equality check predicate on the "upstream_model" field. It's identical to UpstreamModelEQ.
+func UpstreamModel(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldEQ(FieldUpstreamModel, v))
+}
+
 // GroupID applies equality check predicate on the "group_id" field. It's identical to GroupIDEQ.
 func GroupID(v int64) predicate.UsageLog {
 	return predicate.UsageLog(sql.FieldEQ(FieldGroupID, v))
@@ -405,6 +410,81 @@ func ModelContainsFold(v string) predicate.UsageLog {
 	return predicate.UsageLog(sql.FieldContainsFold(FieldModel, v))
 }

+// UpstreamModelEQ applies the EQ predicate on the "upstream_model" field.
+func UpstreamModelEQ(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldEQ(FieldUpstreamModel, v))
+}
+
+// UpstreamModelNEQ applies the NEQ predicate on the "upstream_model" field.
+func UpstreamModelNEQ(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldNEQ(FieldUpstreamModel, v))
+}
+
+// UpstreamModelIn applies the In predicate on the "upstream_model" field.
+func UpstreamModelIn(vs ...string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldIn(FieldUpstreamModel, vs...))
+}
+
+// UpstreamModelNotIn applies the NotIn predicate on the "upstream_model" field.
+func UpstreamModelNotIn(vs ...string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldNotIn(FieldUpstreamModel, vs...))
+}
+
+// UpstreamModelGT applies the GT predicate on the "upstream_model" field.
+func UpstreamModelGT(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldGT(FieldUpstreamModel, v))
+}
+
+// UpstreamModelGTE applies the GTE predicate on the "upstream_model" field.
+func UpstreamModelGTE(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldGTE(FieldUpstreamModel, v))
+}
+
+// UpstreamModelLT applies the LT predicate on the "upstream_model" field.
+func UpstreamModelLT(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldLT(FieldUpstreamModel, v))
+}
+
+// UpstreamModelLTE applies the LTE predicate on the "upstream_model" field.
+func UpstreamModelLTE(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldLTE(FieldUpstreamModel, v))
+}
+
+// UpstreamModelContains applies the Contains predicate on the "upstream_model" field.
+func UpstreamModelContains(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldContains(FieldUpstreamModel, v))
+}
+
+// UpstreamModelHasPrefix applies the HasPrefix predicate on the "upstream_model" field.
+func UpstreamModelHasPrefix(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldHasPrefix(FieldUpstreamModel, v))
+}
+
+// UpstreamModelHasSuffix applies the HasSuffix predicate on the "upstream_model" field.
+func UpstreamModelHasSuffix(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldHasSuffix(FieldUpstreamModel, v))
+}
+
+// UpstreamModelIsNil applies the IsNil predicate on the "upstream_model" field.
+func UpstreamModelIsNil() predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldIsNull(FieldUpstreamModel))
+}
+
+// UpstreamModelNotNil applies the NotNil predicate on the "upstream_model" field.
+func UpstreamModelNotNil() predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldNotNull(FieldUpstreamModel))
+}
+
+// UpstreamModelEqualFold applies the EqualFold predicate on the "upstream_model" field.
+func UpstreamModelEqualFold(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldEqualFold(FieldUpstreamModel, v))
+}
+
+// UpstreamModelContainsFold applies the ContainsFold predicate on the "upstream_model" field.
+func UpstreamModelContainsFold(v string) predicate.UsageLog {
+	return predicate.UsageLog(sql.FieldContainsFold(FieldUpstreamModel, v))
+}
+
 // GroupIDEQ applies the EQ predicate on the "group_id" field.
 func GroupIDEQ(v int64) predicate.UsageLog {
 	return predicate.UsageLog(sql.FieldEQ(FieldGroupID, v))
--- a/backend/ent/usagelog_create.go
+++ b/backend/ent/usagelog_create.go
@@ -57,6 +57,20 @@ func (_c *UsageLogCreate) SetModel(v string) *UsageLogCreate {
 	return _c
 }

+// SetUpstreamModel sets the "upstream_model" field.
+func (_c *UsageLogCreate) SetUpstreamModel(v string) *UsageLogCreate {
+	_c.mutation.SetUpstreamModel(v)
+	return _c
+}
+
+// SetNillableUpstreamModel sets the "upstream_model" field if the given value is not nil.
+func (_c *UsageLogCreate) SetNillableUpstreamModel(v *string) *UsageLogCreate {
+	if v != nil {
+		_c.SetUpstreamModel(*v)
+	}
+	return _c
+}
+
 // SetGroupID sets the "group_id" field.
 func (_c *UsageLogCreate) SetGroupID(v int64) *UsageLogCreate {
 	_c.mutation.SetGroupID(v)
@@ -596,6 +610,11 @@ func (_c *UsageLogCreate) check() error {
 			return &ValidationError{Name: "model", err: fmt.Errorf(`ent: validator failed for field "UsageLog.model": %w`, err)}
 		}
 	}
+	if v, ok := _c.mutation.UpstreamModel(); ok {
+		if err := usagelog.UpstreamModelValidator(v); err != nil {
+			return &ValidationError{Name: "upstream_model", err: fmt.Errorf(`ent: validator failed for field "UsageLog.upstream_model": %w`, err)}
+		}
+	}
 	if _, ok := _c.mutation.InputTokens(); !ok {
 		return &ValidationError{Name: "input_tokens", err: errors.New(`ent: missing required field "UsageLog.input_tokens"`)}
 	}
@@ -714,6 +733,10 @@ func (_c *UsageLogCreate) createSpec() (*UsageLog, *sqlgraph.CreateSpec) {
 		_spec.SetField(usagelog.FieldModel, field.TypeString, value)
 		_node.Model = value
 	}
+	if value, ok := _c.mutation.UpstreamModel(); ok {
+		_spec.SetField(usagelog.FieldUpstreamModel, field.TypeString, value)
+		_node.UpstreamModel = &value
+	}
 	if value, ok := _c.mutation.InputTokens(); ok {
 		_spec.SetField(usagelog.FieldInputTokens, field.TypeInt, value)
 		_node.InputTokens = value
@@ -1011,6 +1034,24 @@ func (u *UsageLogUpsert) UpdateModel() *UsageLogUpsert {
 	return u
 }

+// SetUpstreamModel sets the "upstream_model" field.
+func (u *UsageLogUpsert) SetUpstreamModel(v string) *UsageLogUpsert {
+	u.Set(usagelog.FieldUpstreamModel, v)
+	return u
+}
+
+// UpdateUpstreamModel sets the "upstream_model" field to the value that was provided on create.
+func (u *UsageLogUpsert) UpdateUpstreamModel() *UsageLogUpsert {
+	u.SetExcluded(usagelog.FieldUpstreamModel)
+	return u
+}
+
+// ClearUpstreamModel clears the value of the "upstream_model" field.
+func (u *UsageLogUpsert) ClearUpstreamModel() *UsageLogUpsert {
+	u.SetNull(usagelog.FieldUpstreamModel)
+	return u
+}
+
 // SetGroupID sets the "group_id" field.
 func (u *UsageLogUpsert) SetGroupID(v int64) *UsageLogUpsert {
 	u.Set(usagelog.FieldGroupID, v)
@@ -1600,6 +1641,27 @@ func (u *UsageLogUpsertOne) UpdateModel() *UsageLogUpsertOne {
 	})
 }

+// SetUpstreamModel sets the "upstream_model" field.
+func (u *UsageLogUpsertOne) SetUpstreamModel(v string) *UsageLogUpsertOne {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.SetUpstreamModel(v)
+	})
+}
+
+// UpdateUpstreamModel sets the "upstream_model" field to the value that was provided on create.
+func (u *UsageLogUpsertOne) UpdateUpstreamModel() *UsageLogUpsertOne {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.UpdateUpstreamModel()
+	})
+}
+
+// ClearUpstreamModel clears the value of the "upstream_model" field.
+func (u *UsageLogUpsertOne) ClearUpstreamModel() *UsageLogUpsertOne {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.ClearUpstreamModel()
+	})
+}
+
 // SetGroupID sets the "group_id" field.
 func (u *UsageLogUpsertOne) SetGroupID(v int64) *UsageLogUpsertOne {
 	return u.Update(func(s *UsageLogUpsert) {
@@ -2434,6 +2496,27 @@ func (u *UsageLogUpsertBulk) UpdateModel() *UsageLogUpsertBulk {
 	})
 }

+// SetUpstreamModel sets the "upstream_model" field.
+func (u *UsageLogUpsertBulk) SetUpstreamModel(v string) *UsageLogUpsertBulk {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.SetUpstreamModel(v)
+	})
+}
+
+// UpdateUpstreamModel sets the "upstream_model" field to the value that was provided on create.
+func (u *UsageLogUpsertBulk) UpdateUpstreamModel() *UsageLogUpsertBulk {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.UpdateUpstreamModel()
+	})
+}
+
+// ClearUpstreamModel clears the value of the "upstream_model" field.
+func (u *UsageLogUpsertBulk) ClearUpstreamModel() *UsageLogUpsertBulk {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.ClearUpstreamModel()
+	})
+}
+
 // SetGroupID sets the "group_id" field.
 func (u *UsageLogUpsertBulk) SetGroupID(v int64) *UsageLogUpsertBulk {
 	return u.Update(func(s *UsageLogUpsert) {
--- a/backend/ent/usagelog_update.go
+++ b/backend/ent/usagelog_update.go
@@ -102,6 +102,26 @@ func (_u *UsageLogUpdate) SetNillableModel(v *string) *UsageLogUpdate {
 	return _u
 }

+// SetUpstreamModel sets the "upstream_model" field.
+func (_u *UsageLogUpdate) SetUpstreamModel(v string) *UsageLogUpdate {
+	_u.mutation.SetUpstreamModel(v)
+	return _u
+}
+
+// SetNillableUpstreamModel sets the "upstream_model" field if the given value is not nil.
+func (_u *UsageLogUpdate) SetNillableUpstreamModel(v *string) *UsageLogUpdate {
+	if v != nil {
+		_u.SetUpstreamModel(*v)
+	}
+	return _u
+}
+
+// ClearUpstreamModel clears the value of the "upstream_model" field.
+func (_u *UsageLogUpdate) ClearUpstreamModel() *UsageLogUpdate {
+	_u.mutation.ClearUpstreamModel()
+	return _u
+}
+
 // SetGroupID sets the "group_id" field.
 func (_u *UsageLogUpdate) SetGroupID(v int64) *UsageLogUpdate {
 	_u.mutation.SetGroupID(v)
@@ -745,6 +765,11 @@ func (_u *UsageLogUpdate) check() error {
 			return &ValidationError{Name: "model", err: fmt.Errorf(`ent: validator failed for field "UsageLog.model": %w`, err)}
 		}
 	}
+	if v, ok := _u.mutation.UpstreamModel(); ok {
+		if err := usagelog.UpstreamModelValidator(v); err != nil {
+			return &ValidationError{Name: "upstream_model", err: fmt.Errorf(`ent: validator failed for field "UsageLog.upstream_model": %w`, err)}
+		}
+	}
 	if v, ok := _u.mutation.UserAgent(); ok {
 		if err := usagelog.UserAgentValidator(v); err != nil {
 			return &ValidationError{Name: "user_agent", err: fmt.Errorf(`ent: validator failed for field "UsageLog.user_agent": %w`, err)}
@@ -795,6 +820,12 @@ func (_u *UsageLogUpdate) sqlSave(ctx context.Context) (_node int, err error) {
 	if value, ok := _u.mutation.Model(); ok {
 		_spec.SetField(usagelog.FieldModel, field.TypeString, value)
 	}
+	if value, ok := _u.mutation.UpstreamModel(); ok {
+		_spec.SetField(usagelog.FieldUpstreamModel, field.TypeString, value)
+	}
+	if _u.mutation.UpstreamModelCleared() {
+		_spec.ClearField(usagelog.FieldUpstreamModel, field.TypeString)
+	}
 	if value, ok := _u.mutation.InputTokens(); ok {
 		_spec.SetField(usagelog.FieldInputTokens, field.TypeInt, value)
 	}
@@ -1177,6 +1208,26 @@ func (_u *UsageLogUpdateOne) SetNillableModel(v *string) *UsageLogUpdateOne {
 	return _u
 }

+// SetUpstreamModel sets the "upstream_model" field.
+func (_u *UsageLogUpdateOne) SetUpstreamModel(v string) *UsageLogUpdateOne {
+	_u.mutation.SetUpstreamModel(v)
+	return _u
+}
+
+// SetNillableUpstreamModel sets the "upstream_model" field if the given value is not nil.
+func (_u *UsageLogUpdateOne) SetNillableUpstreamModel(v *string) *UsageLogUpdateOne {
+	if v != nil {
+		_u.SetUpstreamModel(*v)
+	}
+	return _u
+}
+
+// ClearUpstreamModel clears the value of the "upstream_model" field.
+func (_u *UsageLogUpdateOne) ClearUpstreamModel() *UsageLogUpdateOne {
+	_u.mutation.ClearUpstreamModel()
+	return _u
+}
+
 // SetGroupID sets the "group_id" field.
 func (_u *UsageLogUpdateOne) SetGroupID(v int64) *UsageLogUpdateOne {
 	_u.mutation.SetGroupID(v)
@@ -1833,6 +1884,11 @@ func (_u *UsageLogUpdateOne) check() error {
 			return &ValidationError{Name: "model", err: fmt.Errorf(`ent: validator failed for field "UsageLog.model": %w`, err)}
 		}
 	}
+	if v, ok := _u.mutation.UpstreamModel(); ok {
+		if err := usagelog.UpstreamModelValidator(v); err != nil {
+			return &ValidationError{Name: "upstream_model", err: fmt.Errorf(`ent: validator failed for field "UsageLog.upstream_model": %w`, err)}
+		}
+	}
 	if v, ok := _u.mutation.UserAgent(); ok {
 		if err := usagelog.UserAgentValidator(v); err != nil {
 			return &ValidationError{Name: "user_agent", err: fmt.Errorf(`ent: validator failed for field "UsageLog.user_agent": %w`, err)}
@@ -1900,6 +1956,12 @@ func (_u *UsageLogUpdateOne) sqlSave(ctx context.Context) (_node *UsageLog, err
 	if value, ok := _u.mutation.Model(); ok {
 		_spec.SetField(usagelog.FieldModel, field.TypeString, value)
 	}
+	if value, ok := _u.mutation.UpstreamModel(); ok {
+		_spec.SetField(usagelog.FieldUpstreamModel, field.TypeString, value)
+	}
+	if _u.mutation.UpstreamModelCleared() {
+		_spec.ClearField(usagelog.FieldUpstreamModel, field.TypeString)
+	}
 	if value, ok := _u.mutation.InputTokens(); ok {
 		_spec.SetField(usagelog.FieldInputTokens, field.TypeInt, value)
 	}
--- a/backend/go.mod
+++ b/backend/go.mod
@@ -107,6 +107,7 @@ require (
 	github.com/goccy/go-json v0.10.2 // indirect
 	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/google/go-querystring v1.1.0 // indirect
+	github.com/google/subcommands v1.2.0 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.3 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/hashicorp/hcl/v2 v2.18.1 // indirect
@@ -176,6 +177,7 @@ require (
 	golang.org/x/mod v0.32.0 // indirect
 	golang.org/x/sys v0.41.0 // indirect
 	golang.org/x/text v0.34.0 // indirect
+	golang.org/x/tools v0.41.0 // indirect
 	google.golang.org/grpc v1.75.1 // indirect
 	google.golang.org/protobuf v1.36.10 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
--- a/backend/go.sum
+++ b/backend/go.sum
@@ -184,6 +184,8 @@ github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e h1:ijClszYn+mADRFY17kjQEVQ1XRhq2/JR1M3sGqeJoxs=
 github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e/go.mod h1:boTsfXsheKC2y+lKOCMpSfarhxDeIzfZG1jqGcPl3cA=
+github.com/google/subcommands v1.2.0 h1:vWQspBTo2nEqTUFita5/KeEWlUL8kQObDFbub/EN9oE=
+github.com/google/subcommands v1.2.0/go.mod h1:ZjhPrFU+Olkh9WazFPsl27BQ4UPiG37m3yTrtFlrHVk=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/google/wire v0.7.0 h1:JxUKI6+CVBgCO2WToKy/nQk0sS+amI9z9EjVmdaocj4=
@@ -203,6 +205,8 @@ github.com/icholy/digest v1.1.0 h1:HfGg9Irj7i+IX1o1QAmPfIBNu/Q5A5Tu3n/MED9k9H4=
 github.com/icholy/digest v1.1.0/go.mod h1:QNrsSGQ5v7v9cReDI0+eyjsXGUoRSUZQHeQ5C4XLa0Y=
 github.com/imroc/req/v3 v3.57.0 h1:LMTUjNRUybUkTPn8oJDq8Kg3JRBOBTcnDhKu7mzupKI=
 github.com/imroc/req/v3 v3.57.0/go.mod h1:JL62ey1nvSLq81HORNcosvlf7SxZStONNqOprg0Pz00=
+github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
+github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
 github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
 github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
--- a/backend/migrations/075_add_usage_log_upstream_model.sql
+++ b/backend/migrations/075_add_usage_log_upstream_model.sql
@@ -0,0 +1,4 @@
+-- Add upstream_model field to usage_logs.
+-- Stores the actual upstream model name when it differs from the requested model
+-- (i.e., when model mapping is applied). NULL means no mapping was applied.
+ALTER TABLE usage_logs ADD COLUMN IF NOT EXISTS upstream_model VARCHAR(100);
--- a/backend/migrations/076_add_usage_log_upstream_model_index_notx.sql
+++ b/backend/migrations/076_add_usage_log_upstream_model_index_notx.sql
@@ -0,0 +1,3 @@
+-- Support upstream_model / mapping model distribution aggregations with time-range filters.
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_usage_logs_created_model_upstream_model
+ON usage_logs (created_at, model, upstream_model);
--- a/backend/migrations/README.md
+++ b/backend/migrations/README.md
@@ -34,18 +34,18 @@ Example: `017_add_gemini_tier_id.sql`

 ## Migration File Structure

-```sql
-- +goose Up
-- +goose StatementBegin
-- Your forward migration SQL here
-- +goose StatementEnd
+This project uses a custom migration runner (`internal/repository/migrations_runner.go`) that executes the full SQL file content as-is.

-- +goose Down
-- +goose StatementBegin
-- Your rollback migration SQL here
-- +goose StatementEnd
+- Regular migrations (`*.sql`): executed in a transaction.
+- Non-transactional migrations (`*_notx.sql`): split by statement and executed without transaction (for `CONCURRENTLY`).
+
+```sql
+-- Forward-only migration (recommended)
+ALTER TABLE usage_logs ADD COLUMN IF NOT EXISTS example_column VARCHAR(100);
 ```

+> ⚠️ Do **not** place executable "Down" SQL in the same file. The runner does not parse goose Up/Down sections and will execute all SQL statements in the file.
+
 ## Important Rules

 ### ⚠️ Immutability Principle
@@ -66,9 +66,9 @@ Why?
   touch migrations/018_your_change.sql
   ```

-2. **Write Up and Down migrations**
-   - Up: Apply the change
-   - Down: Revert the change (should be symmetric with Up)
+2. **Write forward-only migration SQL**
+   - Put only the intended schema change in the file
+   - If rollback is needed, create a new migration file to revert

 3. **Test locally**
   ```bash
@@ -144,8 +144,6 @@ touch migrations/018_your_new_change.sql
 ## Example Migration

 ```sql
-- +goose Up
-- +goose StatementBegin
 -- Add tier_id field to Gemini OAuth accounts for quota tracking
 UPDATE accounts
 SET credentials = jsonb_set(
@@ -157,17 +155,6 @@ SET credentials = jsonb_set(
 WHERE platform = 'gemini'
  AND type = 'oauth'
  AND credentials->>'tier_id' IS NULL;
-- +goose StatementEnd
-
-- +goose Down
-- +goose StatementBegin
-- Remove tier_id field
-UPDATE accounts
-SET credentials = credentials - 'tier_id'
-WHERE platform = 'gemini'
-  AND type = 'oauth'
-  AND credentials->>'tier_id' = 'LEGACY';
-- +goose StatementEnd
 ```

 ## Troubleshooting
@@ -194,5 +181,4 @@ VALUES ('NNN_migration.sql', 'calculated_checksum', NOW());
 ## References

 - Migration runner: `internal/repository/migrations_runner.go`
- Goose syntax: https://github.com/pressly/goose
 - PostgreSQL docs: https://www.postgresql.org/docs/