diff --git a/go.mod b/go.mod
index 8d009f8..827c6da 100644
--- a/go.mod
+++ b/go.mod
@@ -13,6 +13,22 @@ require (
 	github.com/joho/godotenv v1.5.1
 	github.com/mattn/go-sqlite3 v1.14.32
 	github.com/swaggo/http-swagger v1.3.4
-	github.com/swaggo/swag v1.16.4
 	golang.org/x/crypto v0.45.0
 )
+
+require (
+	github.com/KyleBanks/depth v1.2.1 // indirect
+	github.com/cespare/xxhash/v2 v2.1.2 // indirect
+	github.com/go-openapi/jsonpointer v0.19.5 // indirect
+	github.com/go-openapi/jsonreference v0.20.0 // indirect
+	github.com/go-openapi/spec v0.20.6 // indirect
+	github.com/go-openapi/swag v0.19.15 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/mailru/easyjson v0.7.6 // indirect
+	github.com/swaggo/files v0.0.0-20220610200504-28940afbdbfe // indirect
+	github.com/swaggo/swag v1.16.4 // indirect
+	golang.org/x/net v0.47.0 // indirect
+	golang.org/x/sys v0.38.0 // indirect
+	golang.org/x/tools v0.7.0 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+)
diff --git a/go.sum b/go.sum
index 5364729..6993573 100644
--- a/go.sum
+++ b/go.sum
@@ -1,14 +1,85 @@
+github.com/KyleBanks/depth v1.2.1 h1:5h8fQADFrWtarTdtDudMmGsC7GPbOAu6RVB3ffsVFHc=
+github.com/KyleBanks/depth v1.2.1/go.mod h1:jzSb9d0L43HxTQfT+oSA1EEp2q+ne2uh6XgeJcm8brE=
+github.com/cespare/xxhash/v2 v2.1.2 h1:YRXhKfTDauu4ajMg1TPgFO5jnlC2HCbmLXMcTG5cbYE=
+github.com/cespare/xxhash/v2 v2.1.2/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-chi/chi/v5 v5.2.3 h1:WQIt9uxdsAbgIYgid+BpYc+liqQZGMHRaUwp0JUcvdE=
 github.com/go-chi/chi/v5 v5.2.3/go.mod h1:L2yAIGWB3H+phAw1NxKwWM+7eUH/lU8pOMm5hHcoops=
 github.com/go-chi/cors v1.2.2 h1:Jmey33TE+b+rB7fT8MUy1u0I4L+NARQlK6LhzKPSyQE=
 github.com/go-chi/cors v1.2.2/go.mod h1:sSbTewc+6wYHBBCW7ytsFSn836hqM7JxpglAy2Vzc58=
+github.com/go-chi/httprate v0.7.4 h1:a2GIjv8he9LRf3712zxxnRdckQCm7I8y8yQhkJ84V6M=
+github.com/go-chi/httprate v0.7.4/go.mod h1:6GOYBSwnpra4CQfAKXu8sQZg+nZ0M1g9QnyFvxrAB8A=
+github.com/go-openapi/jsonpointer v0.19.3/go.mod h1:Pl9vOtqEWErmShwVjC8pYs9cog34VGT37dQOVbmoatg=
+github.com/go-openapi/jsonpointer v0.19.5 h1:gZr+CIYByUqjcgeLXnQu2gHYQC9o73G2XUeOFYEICuY=
+github.com/go-openapi/jsonpointer v0.19.5/go.mod h1:Pl9vOtqEWErmShwVjC8pYs9cog34VGT37dQOVbmoatg=
+github.com/go-openapi/jsonreference v0.20.0 h1:MYlu0sBgChmCfJxxUKZ8g1cPWFOB37YSZqewK7OKeyA=
+github.com/go-openapi/jsonreference v0.20.0/go.mod h1:Ag74Ico3lPc+zR+qjn4XBUmXymS4zJbYVCZmcgkasdo=
+github.com/go-openapi/spec v0.20.6 h1:ich1RQ3WDbfoeTqTAb+5EIxNmpKVJZWBNah9RAT0jIQ=
+github.com/go-openapi/spec v0.20.6/go.mod h1:2OpW+JddWPrpXSCIX8eOx7lZ5iyuWj3RYR6VaaBKcWA=
+github.com/go-openapi/swag v0.19.5/go.mod h1:POnQmlKehdgb5mhVOsnJFsivZCEZ/vjK9gh66Z9tfKk=
+github.com/go-openapi/swag v0.19.15 h1:D2NRCBzS9/pEY3gP9Nl8aDqGUcPFrwG2p+CNFrLyrCM=
+github.com/go-openapi/swag v0.19.15/go.mod h1:QYRuS/SOXUCsnplDa677K7+DxSOj6IPNl/eQntq43wQ=
 github.com/golang-jwt/jwt/v5 v5.3.0 h1:pv4AsKCKKZuqlgs5sUmn4x8UlGa0kEVt/puTpKx9vvo=
 github.com/golang-jwt/jwt/v5 v5.3.0/go.mod h1:fxCRLWMO43lRc8nhHWY6LGqRcf+1gQWArsqaEUEa5bE=
 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/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
 github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
+github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
+github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
+github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/mailru/easyjson v0.0.0-20190614124828-94de47d64c63/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=
+github.com/mailru/easyjson v0.0.0-20190626092158-b2ccc519800e/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=
+github.com/mailru/easyjson v0.7.6 h1:8yTIVnZgCoiM1TgqoeTl+LfU5Jg6/xL3QhGQnimLYnA=
+github.com/mailru/easyjson v0.7.6/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/mattn/go-sqlite3 v1.14.32 h1:JD12Ag3oLy1zQA+BNn74xRgaBbdhbNIDYvQUEuuErjs=
 github.com/mattn/go-sqlite3 v1.14.32/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
+github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
+github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/swaggo/files v0.0.0-20220610200504-28940afbdbfe h1:K8pHPVoTgxFJt1lXuIzzOX7zZhZFldJQK/CgKx9BFIc=
+github.com/swaggo/files v0.0.0-20220610200504-28940afbdbfe/go.mod h1:lKJPbtWzJ9JhsTN1k1gZgleJWY/cqq0psdoMmaThG3w=
+github.com/swaggo/http-swagger v1.3.4 h1:q7t/XLx0n15H1Q9/tk3Y9L4n210XzJF5WtnDX64a5ww=
+github.com/swaggo/http-swagger v1.3.4/go.mod h1:9dAh0unqMBAlbp1uE2Uc2mQTxNMU/ha4UbucIg1MFkQ=
+github.com/swaggo/swag v1.16.4 h1:clWJtd9LStiG3VeijiCfOVODP6VpHtKdQy9ELFG3s1A=
+github.com/swaggo/swag v1.16.4/go.mod h1:VBsHJRsDvfYvqoiMKnsdwhNV9LEMHgEDZcyVYX0sxPg=
 golang.org/x/crypto v0.45.0 h1:jMBrvKuj23MTlT0bQEOBcAE0mjg8mK9RXFhRH6nyF3Q=
 golang.org/x/crypto v0.45.0/go.mod h1:XTGrrkGJve7CYK7J8PEww4aY7gM3qMCElcJQ8n8JdX4=
+golang.org/x/mod v0.9.0 h1:KENHtAZL2y3NLMYZeHY9DW8HW8V+kQyJsY/V9JlKvCs=
+golang.org/x/mod v0.9.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/net v0.0.0-20210805182204-aaa1db679c0d/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.47.0 h1:Mx+4dIFzqraBXUugkia1OOvlD6LemFo1ALMHjrXDOhY=
+golang.org/x/net v0.47.0/go.mod h1:/jNxtkgq5yWUGYkaZGqo27cfGZ1c5Nen03aYrrKpVRU=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
+golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.7.0 h1:W4OVu8VVOaIO0yzWMNdepAulS7YfoS3Zabrm8DOXXU4=
+golang.org/x/tools v0.7.0/go.mod h1:4pg6aUX35JBAogB10C9AtvVL+qowtN4pT3CGSQex14s=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU=
+gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.0 h1:hjy8E9ON/egN1tAYqKb61G10WtihqetD4sz2H+8nIeA=
+gopkg.in/yaml.v3 v3.0.0/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/internal/application/commands/archive_habit_test.go b/internal/application/commands/archive_habit_test.go
index 89af63b..d807ef7 100644
--- a/internal/application/commands/archive_habit_test.go
+++ b/internal/application/commands/archive_habit_test.go
@@ -10,7 +10,7 @@ import (
 )
 
 func TestArchiveHabitHandler_ArchivesSuccessfully(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForUpdate{
@@ -59,7 +59,7 @@ func TestArchiveHabitHandler_ReturnsErrorWhenHabitNotFound(t *testing.T) {
 }
 
 func TestArchiveHabitHandler_ReturnsErrorWhenUserDoesNotOwnHabit(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForUpdate{
@@ -81,7 +81,7 @@ func TestArchiveHabitHandler_ReturnsErrorWhenUserDoesNotOwnHabit(t *testing.T) {
 }
 
 func TestArchiveHabitHandler_CanArchiveAlreadyArchivedHabit(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 	habit.Archive()
 
diff --git a/internal/application/commands/create_habit.go b/internal/application/commands/create_habit.go
index 7927379..6b89d43 100644
--- a/internal/application/commands/create_habit.go
+++ b/internal/application/commands/create_habit.go
@@ -18,6 +18,7 @@ type CreateHabitCommand struct {
 	SpecificDays  []int
 	SpecificDates []int
 	CarryOver     bool
+	IsNegative    bool
 	TargetValue   *float64
 }
 
@@ -46,7 +47,7 @@ func (h *CreateHabitHandler) Handle(ctx context.Context, cmd CreateHabitCommand)
 		return "", errors.ErrInvalidInput
 	}
 
-	habit := entities.NewHabit(cmd.UserID, cmd.Name, cmd.Type, cmd.Frequency, cmd.CarryOver)
+	habit := entities.NewHabit(cmd.UserID, cmd.Name, cmd.Type, cmd.Frequency, cmd.CarryOver, cmd.IsNegative)
 	habit.Description = cmd.Description
 	habit.SpecificDays = cmd.SpecificDays
 	habit.SpecificDates = cmd.SpecificDates
diff --git a/internal/application/commands/create_habit_test.go b/internal/application/commands/create_habit_test.go
index 2922100..54df206 100644
--- a/internal/application/commands/create_habit_test.go
+++ b/internal/application/commands/create_habit_test.go
@@ -195,3 +195,37 @@ func TestCreateHabitHandler_MonthlyWithSpecificDates(t *testing.T) {
 		t.Fatalf("Expected no error, got %v", err)
 	}
 }
+
+func TestCreateHabitHandler_NegativeHabit(t *testing.T) {
+	mock := &mockHabitRepo{
+		createFunc: func(ctx context.Context, habit *entities.Habit) error {
+			habit.ID = "habit-123"
+			if !habit.IsNegative {
+				t.Error("Expected IsNegative to be true")
+			}
+			return nil
+		},
+	}
+
+	handler := NewCreateHabitHandler(mock)
+
+	cmd := CreateHabitCommand{
+		UserID:      "user-123",
+		Name:        "Eat Candy",
+		Description: "Track bad habit",
+		Type:        "COUNTER",
+		Frequency:   "DAILY",
+		CarryOver:   false,
+		IsNegative:  true,
+	}
+
+	habitID, err := handler.Handle(context.Background(), cmd)
+
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+
+	if habitID == "" {
+		t.Error("Expected habit ID to be returned")
+	}
+}
diff --git a/internal/application/commands/mark_habit.go b/internal/application/commands/mark_habit.go
index 96add39..b55ff6a 100644
--- a/internal/application/commands/mark_habit.go
+++ b/internal/application/commands/mark_habit.go
@@ -3,10 +3,13 @@ package commands
 import (
 	"context"
 	"fmt"
+	"math"
 	"time"
 
 	"apocapoc-api/internal/domain/entities"
 	"apocapoc-api/internal/domain/repositories"
+	"apocapoc-api/internal/domain/value_objects"
+	"apocapoc-api/internal/shared/errors"
 )
 
 type MarkHabitCommand struct {
@@ -44,7 +47,61 @@ func (h *MarkHabitHandler) Handle(ctx context.Context, cmd MarkHabitCommand) err
 		return fmt.Errorf("habit is archived")
 	}
 
-	entry := entities.NewHabitEntry(cmd.HabitID, cmd.ScheduledDate, cmd.Value)
+	if habit.Type == value_objects.HabitTypeCounter && cmd.Value != nil {
+		if *cmd.Value != math.Floor(*cmd.Value) {
+			return errors.ErrInvalidInput
+		}
+	}
+
+	var finalValue *float64
+
+	if habit.Type == value_objects.HabitTypeCounter {
+		startOfDay := time.Date(cmd.ScheduledDate.Year(), cmd.ScheduledDate.Month(), cmd.ScheduledDate.Day(), 0, 0, 0, 0, cmd.ScheduledDate.Location())
+		endOfDay := startOfDay.Add(24 * time.Hour).Add(-time.Nanosecond)
+
+		existingEntries, _ := h.entryRepo.FindByHabitIDAndDateRange(ctx, cmd.HabitID, startOfDay, endOfDay)
+
+		if len(existingEntries) > 0 {
+			existingEntry := existingEntries[0]
+
+			var increment float64 = 1.0
+			if cmd.Value != nil {
+				increment = *cmd.Value
+			}
+
+			var newValue float64
+			if existingEntry.Value != nil {
+				newValue = *existingEntry.Value + increment
+			} else {
+				newValue = increment
+			}
+
+			if newValue < 0 {
+				newValue = 0
+			}
+
+			finalValue = &newValue
+			existingEntry.Value = finalValue
+			existingEntry.CompletedAt = time.Now()
+
+			return h.entryRepo.Update(ctx, existingEntry)
+		} else {
+			if cmd.Value != nil {
+				value := *cmd.Value
+				if value < 0 {
+					value = 0
+				}
+				finalValue = &value
+			} else {
+				defaultValue := 1.0
+				finalValue = &defaultValue
+			}
+		}
+	} else {
+		finalValue = cmd.Value
+	}
+
+	entry := entities.NewHabitEntry(cmd.HabitID, cmd.ScheduledDate, finalValue)
 
 	return h.entryRepo.Create(ctx, entry)
 }
diff --git a/internal/application/commands/mark_habit_test.go b/internal/application/commands/mark_habit_test.go
index 9eb18fd..d66648d 100644
--- a/internal/application/commands/mark_habit_test.go
+++ b/internal/application/commands/mark_habit_test.go
@@ -11,7 +11,9 @@ import (
 )
 
 type mockEntryRepo struct {
-	createFunc func(ctx context.Context, entry *entities.HabitEntry) error
+	createFunc               func(ctx context.Context, entry *entities.HabitEntry) error
+	findByDateRangeFunc      func(ctx context.Context, habitID string, from, to time.Time) ([]*entities.HabitEntry, error)
+	updateFunc               func(ctx context.Context, entry *entities.HabitEntry) error
 }
 
 func (m *mockEntryRepo) Create(ctx context.Context, entry *entities.HabitEntry) error {
@@ -30,6 +32,9 @@ func (m *mockEntryRepo) FindByHabitID(ctx context.Context, habitID string) ([]*e
 }
 
 func (m *mockEntryRepo) FindByHabitIDAndDateRange(ctx context.Context, habitID string, from, to time.Time) ([]*entities.HabitEntry, error) {
+	if m.findByDateRangeFunc != nil {
+		return m.findByDateRangeFunc(ctx, habitID, from, to)
+	}
 	return nil, nil
 }
 
@@ -38,6 +43,9 @@ func (m *mockEntryRepo) FindPendingByHabitID(ctx context.Context, habitID string
 }
 
 func (m *mockEntryRepo) Update(ctx context.Context, entry *entities.HabitEntry) error {
+	if m.updateFunc != nil {
+		return m.updateFunc(ctx, entry)
+	}
 	return nil
 }
 
@@ -74,7 +82,7 @@ func (m *mockHabitRepoForMark) Delete(ctx context.Context, id string) error {
 }
 
 func TestMarkHabitHandler_Success(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForMark{habit: habit}
@@ -122,7 +130,7 @@ func TestMarkHabitHandler_HabitNotFound(t *testing.T) {
 }
 
 func TestMarkHabitHandler_ArchivedHabit(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 	habit.Archive()
 
@@ -144,7 +152,7 @@ func TestMarkHabitHandler_ArchivedHabit(t *testing.T) {
 }
 
 func TestMarkHabitHandler_WithValue(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Steps", value_objects.HabitTypeValue, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Steps", value_objects.HabitTypeValue, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForMark{habit: habit}
@@ -179,7 +187,7 @@ func TestMarkHabitHandler_WithValue(t *testing.T) {
 }
 
 func TestMarkHabitHandler_DuplicateEntry(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForMark{habit: habit}
@@ -202,3 +210,332 @@ func TestMarkHabitHandler_DuplicateEntry(t *testing.T) {
 		t.Errorf("Expected ErrAlreadyExists, got %v", err)
 	}
 }
+
+func TestMarkHabitHandler_CounterOnlyAcceptsIntegers(t *testing.T) {
+	habit := entities.NewHabit("user-123", "Water Glasses", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
+	habit.ID = "habit-1"
+
+	habitRepo := &mockHabitRepoForMark{habit: habit}
+	entryRepo := &mockEntryRepo{}
+
+	handler := NewMarkHabitHandler(entryRepo, habitRepo)
+
+	decimalValue := 2.5
+	cmd := MarkHabitCommand{
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &decimalValue,
+	}
+
+	err := handler.Handle(context.Background(), cmd)
+
+	if err != errors.ErrInvalidInput {
+		t.Errorf("Expected ErrInvalidInput for decimal value on COUNTER, got %v", err)
+	}
+}
+
+func TestMarkHabitHandler_CounterAcceptsIntegers(t *testing.T) {
+	habit := entities.NewHabit("user-123", "Water Glasses", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
+	habit.ID = "habit-1"
+
+	habitRepo := &mockHabitRepoForMark{habit: habit}
+	entryRepo := &mockEntryRepo{
+		createFunc: func(ctx context.Context, entry *entities.HabitEntry) error {
+			if entry.Value == nil || *entry.Value != 3.0 {
+				t.Errorf("Expected value 3.0, got %v", entry.Value)
+			}
+			return nil
+		},
+	}
+
+	handler := NewMarkHabitHandler(entryRepo, habitRepo)
+
+	intValue := 3.0
+	cmd := MarkHabitCommand{
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &intValue,
+	}
+
+	err := handler.Handle(context.Background(), cmd)
+
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+}
+
+func TestMarkHabitHandler_CounterAutoIncrementFirstMark(t *testing.T) {
+	habit := entities.NewHabit("user-123", "Water Glasses", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
+	habit.ID = "habit-1"
+
+	habitRepo := &mockHabitRepoForMark{habit: habit}
+	entryRepo := &mockEntryRepo{
+		findByDateRangeFunc: func(ctx context.Context, habitID string, from, to time.Time) ([]*entities.HabitEntry, error) {
+			return []*entities.HabitEntry{}, nil
+		},
+		createFunc: func(ctx context.Context, entry *entities.HabitEntry) error {
+			if entry.Value == nil || *entry.Value != 1.0 {
+				t.Errorf("Expected default value 1.0, got %v", entry.Value)
+			}
+			return nil
+		},
+	}
+
+	handler := NewMarkHabitHandler(entryRepo, habitRepo)
+
+	cmd := MarkHabitCommand{
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         nil,
+	}
+
+	err := handler.Handle(context.Background(), cmd)
+
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+}
+
+func TestMarkHabitHandler_CounterAutoIncrementSubsequentMarks(t *testing.T) {
+	habit := entities.NewHabit("user-123", "Water Glasses", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
+	habit.ID = "habit-1"
+
+	habitRepo := &mockHabitRepoForMark{habit: habit}
+
+	existingValue := 3.0
+	existingEntry := &entities.HabitEntry{
+		ID:            "entry-1",
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &existingValue,
+	}
+
+	entryRepo := &mockEntryRepo{
+		findByDateRangeFunc: func(ctx context.Context, habitID string, from, to time.Time) ([]*entities.HabitEntry, error) {
+			return []*entities.HabitEntry{existingEntry}, nil
+		},
+		updateFunc: func(ctx context.Context, entry *entities.HabitEntry) error {
+			if entry.Value == nil || *entry.Value != 4.0 {
+				t.Errorf("Expected value 4.0, got %v", entry.Value)
+			}
+			return nil
+		},
+	}
+
+	handler := NewMarkHabitHandler(entryRepo, habitRepo)
+
+	cmd := MarkHabitCommand{
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         nil,
+	}
+
+	err := handler.Handle(context.Background(), cmd)
+
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+}
+
+func TestMarkHabitHandler_CounterAutoIncrementWithCustomValue(t *testing.T) {
+	habit := entities.NewHabit("user-123", "Water Glasses", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
+	habit.ID = "habit-1"
+
+	habitRepo := &mockHabitRepoForMark{habit: habit}
+
+	existingValue := 3.0
+	existingEntry := &entities.HabitEntry{
+		ID:            "entry-1",
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &existingValue,
+	}
+
+	entryRepo := &mockEntryRepo{
+		findByDateRangeFunc: func(ctx context.Context, habitID string, from, to time.Time) ([]*entities.HabitEntry, error) {
+			return []*entities.HabitEntry{existingEntry}, nil
+		},
+		updateFunc: func(ctx context.Context, entry *entities.HabitEntry) error {
+			if entry.Value == nil || *entry.Value != 5.0 {
+				t.Errorf("Expected value 5.0 (3+2), got %v", entry.Value)
+			}
+			return nil
+		},
+	}
+
+	handler := NewMarkHabitHandler(entryRepo, habitRepo)
+
+	increment := 2.0
+	cmd := MarkHabitCommand{
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &increment,
+	}
+
+	err := handler.Handle(context.Background(), cmd)
+
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+}
+
+func TestMarkHabitHandler_CounterCanDecrement(t *testing.T) {
+	habit := entities.NewHabit("user-123", "Cigarettes", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
+	habit.ID = "habit-1"
+
+	habitRepo := &mockHabitRepoForMark{habit: habit}
+
+	existingValue := 5.0
+	existingEntry := &entities.HabitEntry{
+		ID:            "entry-1",
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &existingValue,
+	}
+
+	entryRepo := &mockEntryRepo{
+		findByDateRangeFunc: func(ctx context.Context, habitID string, from, to time.Time) ([]*entities.HabitEntry, error) {
+			return []*entities.HabitEntry{existingEntry}, nil
+		},
+		updateFunc: func(ctx context.Context, entry *entities.HabitEntry) error {
+			if entry.Value == nil || *entry.Value != 3.0 {
+				t.Errorf("Expected value 3.0 (5-2), got %v", entry.Value)
+			}
+			return nil
+		},
+	}
+
+	handler := NewMarkHabitHandler(entryRepo, habitRepo)
+
+	decrement := -2.0
+	cmd := MarkHabitCommand{
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &decrement,
+	}
+
+	err := handler.Handle(context.Background(), cmd)
+
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+}
+
+func TestMarkHabitHandler_CounterMinimumZero(t *testing.T) {
+	habit := entities.NewHabit("user-123", "Water Glasses", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
+	habit.ID = "habit-1"
+
+	habitRepo := &mockHabitRepoForMark{habit: habit}
+
+	existingValue := 2.0
+	existingEntry := &entities.HabitEntry{
+		ID:            "entry-1",
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &existingValue,
+	}
+
+	entryRepo := &mockEntryRepo{
+		findByDateRangeFunc: func(ctx context.Context, habitID string, from, to time.Time) ([]*entities.HabitEntry, error) {
+			return []*entities.HabitEntry{existingEntry}, nil
+		},
+		updateFunc: func(ctx context.Context, entry *entities.HabitEntry) error {
+			if entry.Value == nil || *entry.Value != 0.0 {
+				t.Errorf("Expected value 0.0 (2-3 clamped to 0), got %v", entry.Value)
+			}
+			return nil
+		},
+	}
+
+	handler := NewMarkHabitHandler(entryRepo, habitRepo)
+
+	decrement := -3.0
+	cmd := MarkHabitCommand{
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &decrement,
+	}
+
+	err := handler.Handle(context.Background(), cmd)
+
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+}
+
+func TestMarkHabitHandler_CounterStaysAtZero(t *testing.T) {
+	habit := entities.NewHabit("user-123", "Water Glasses", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
+	habit.ID = "habit-1"
+
+	habitRepo := &mockHabitRepoForMark{habit: habit}
+
+	existingValue := 0.0
+	existingEntry := &entities.HabitEntry{
+		ID:            "entry-1",
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &existingValue,
+	}
+
+	entryRepo := &mockEntryRepo{
+		findByDateRangeFunc: func(ctx context.Context, habitID string, from, to time.Time) ([]*entities.HabitEntry, error) {
+			return []*entities.HabitEntry{existingEntry}, nil
+		},
+		updateFunc: func(ctx context.Context, entry *entities.HabitEntry) error {
+			if entry.Value == nil || *entry.Value != 0.0 {
+				t.Errorf("Expected value to stay at 0.0, got %v", entry.Value)
+			}
+			return nil
+		},
+	}
+
+	handler := NewMarkHabitHandler(entryRepo, habitRepo)
+
+	decrement := -1.0
+	cmd := MarkHabitCommand{
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &decrement,
+	}
+
+	err := handler.Handle(context.Background(), cmd)
+
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+}
+
+func TestMarkHabitHandler_CounterFirstMarkWithNegative(t *testing.T) {
+	habit := entities.NewHabit("user-123", "Water Glasses", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
+	habit.ID = "habit-1"
+
+	habitRepo := &mockHabitRepoForMark{habit: habit}
+	entryRepo := &mockEntryRepo{
+		findByDateRangeFunc: func(ctx context.Context, habitID string, from, to time.Time) ([]*entities.HabitEntry, error) {
+			return []*entities.HabitEntry{}, nil
+		},
+		createFunc: func(ctx context.Context, entry *entities.HabitEntry) error {
+			if entry.Value == nil || *entry.Value != 0.0 {
+				t.Errorf("Expected value 0.0 (negative clamped), got %v", entry.Value)
+			}
+			return nil
+		},
+	}
+
+	handler := NewMarkHabitHandler(entryRepo, habitRepo)
+
+	negativeValue := -5.0
+	cmd := MarkHabitCommand{
+		HabitID:       "habit-1",
+		ScheduledDate: time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC),
+		Value:         &negativeValue,
+	}
+
+	err := handler.Handle(context.Background(), cmd)
+
+	if err != nil {
+		t.Fatalf("Expected no error, got %v", err)
+	}
+}
+
+
diff --git a/internal/application/commands/unmark_habit_test.go b/internal/application/commands/unmark_habit_test.go
index 9e04506..797c2a6 100644
--- a/internal/application/commands/unmark_habit_test.go
+++ b/internal/application/commands/unmark_habit_test.go
@@ -30,7 +30,7 @@ func (m *mockEntryRepoForUnmark) Delete(ctx context.Context, id string) error {
 }
 
 func TestUnmarkHabitHandler_UnmarksSuccessfully(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	scheduledDate := time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC)
@@ -87,7 +87,7 @@ func TestUnmarkHabitHandler_ReturnsErrorWhenHabitNotFound(t *testing.T) {
 }
 
 func TestUnmarkHabitHandler_ReturnsErrorWhenUserDoesNotOwnHabit(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForUpdate{
@@ -112,7 +112,7 @@ func TestUnmarkHabitHandler_ReturnsErrorWhenUserDoesNotOwnHabit(t *testing.T) {
 }
 
 func TestUnmarkHabitHandler_ReturnsErrorWhenEntryNotFound(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForUpdate{
diff --git a/internal/application/commands/update_habit_test.go b/internal/application/commands/update_habit_test.go
index 8962094..2861da2 100644
--- a/internal/application/commands/update_habit_test.go
+++ b/internal/application/commands/update_habit_test.go
@@ -33,7 +33,7 @@ func (m *mockHabitRepoForUpdate) Update(ctx context.Context, habit *entities.Hab
 }
 
 func TestUpdateHabitHandler_UpdatesSuccessfully(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForUpdate{
@@ -101,7 +101,7 @@ func TestUpdateHabitHandler_ReturnsErrorWhenHabitNotFound(t *testing.T) {
 }
 
 func TestUpdateHabitHandler_ReturnsErrorWhenUserDoesNotOwnHabit(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForUpdate{
@@ -124,7 +124,7 @@ func TestUpdateHabitHandler_ReturnsErrorWhenUserDoesNotOwnHabit(t *testing.T) {
 }
 
 func TestUpdateHabitHandler_CannotUpdateArchivedHabit(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 	habit.Archive()
 
@@ -148,7 +148,7 @@ func TestUpdateHabitHandler_CannotUpdateArchivedHabit(t *testing.T) {
 }
 
 func TestUpdateHabitHandler_ValidatesInput(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoForUpdate{
diff --git a/internal/application/queries/get_habit_by_id.go b/internal/application/queries/get_habit_by_id.go
index 2a2fa9d..a18cf6e 100644
--- a/internal/application/queries/get_habit_by_id.go
+++ b/internal/application/queries/get_habit_by_id.go
@@ -39,6 +39,7 @@ func (h *GetHabitByIDHandler) Handle(ctx context.Context, query GetHabitByIDQuer
 		Frequency:    habit.Frequency,
 		TargetValue:  habit.TargetValue,
 		CarryOver:    habit.CarryOver,
+		IsNegative:   habit.IsNegative,
 		SpecificDays: habit.SpecificDays,
 	}, nil
 }
diff --git a/internal/application/queries/get_habit_by_id_test.go b/internal/application/queries/get_habit_by_id_test.go
index bcd98a4..f6e578a 100644
--- a/internal/application/queries/get_habit_by_id_test.go
+++ b/internal/application/queries/get_habit_by_id_test.go
@@ -24,7 +24,7 @@ func (m *mockHabitRepoWithFindByID) FindByID(ctx context.Context, id string) (*e
 
 func TestGetHabitByIDHandler_ReturnsHabitSuccessfully(t *testing.T) {
 	targetValue := 5.0
-	habit := entities.NewHabit("user-123", "Drink Water", value_objects.HabitTypeValue, value_objects.FrequencyDaily, true)
+	habit := entities.NewHabit("user-123", "Drink Water", value_objects.HabitTypeValue, value_objects.FrequencyDaily, true, false)
 	habit.ID = "habit-1"
 	habit.TargetValue = &targetValue
 
@@ -82,7 +82,7 @@ func TestGetHabitByIDHandler_ReturnsErrorWhenHabitNotFound(t *testing.T) {
 }
 
 func TestGetHabitByIDHandler_ReturnsErrorWhenUserDoesNotOwnHabit(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoWithFindByID{
diff --git a/internal/application/queries/get_habit_entries_test.go b/internal/application/queries/get_habit_entries_test.go
index e7d2ab6..b4747d2 100644
--- a/internal/application/queries/get_habit_entries_test.go
+++ b/internal/application/queries/get_habit_entries_test.go
@@ -25,7 +25,7 @@ func (m *mockEntryRepoWithFindByHabitID) FindByHabitIDAndDateRange(ctx context.C
 }
 
 func TestGetHabitEntriesHandler_ReturnsEntriesSuccessfully(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	date1 := time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC)
@@ -101,7 +101,7 @@ func TestGetHabitEntriesHandler_ReturnsErrorWhenHabitNotFound(t *testing.T) {
 }
 
 func TestGetHabitEntriesHandler_ReturnsErrorWhenUserDoesNotOwnHabit(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoWithFindByID{
@@ -127,7 +127,7 @@ func TestGetHabitEntriesHandler_ReturnsErrorWhenUserDoesNotOwnHabit(t *testing.T
 }
 
 func TestGetHabitEntriesHandler_WithPagination(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	entries := make([]*entities.HabitEntry, 10)
@@ -179,7 +179,7 @@ func TestGetHabitEntriesHandler_WithPagination(t *testing.T) {
 }
 
 func TestGetHabitEntriesHandler_RequiresPaginationWithoutDateRange(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepoWithFindByID{
@@ -207,7 +207,7 @@ func TestGetHabitEntriesHandler_RequiresPaginationWithoutDateRange(t *testing.T)
 }
 
 func TestGetHabitEntriesHandler_AllowsNoPaginationWithShortDateRange(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	from := time.Date(2025, 1, 1, 0, 0, 0, 0, time.UTC)
@@ -247,7 +247,7 @@ func TestGetHabitEntriesHandler_AllowsNoPaginationWithShortDateRange(t *testing.
 }
 
 func TestGetHabitEntriesHandler_RequiresPaginationWithLongDateRange(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	from := time.Date(2023, 1, 1, 0, 0, 0, 0, time.UTC)
diff --git a/internal/application/queries/get_todays_habits.go b/internal/application/queries/get_todays_habits.go
index 8d9f98b..e9d820b 100644
--- a/internal/application/queries/get_todays_habits.go
+++ b/internal/application/queries/get_todays_habits.go
@@ -14,6 +14,7 @@ type TodaysHabitDTO struct {
 	Name          string
 	Type          value_objects.HabitType
 	TargetValue   *float64
+	IsNegative    bool
 	ScheduledDate time.Time
 	IsCarriedOver bool
 }
@@ -83,6 +84,7 @@ func (h *GetTodaysHabitsHandler) Handle(
 				Name:          habit.Name,
 				Type:          habit.Type,
 				TargetValue:   habit.TargetValue,
+				IsNegative:    habit.IsNegative,
 				ScheduledDate: query.Date,
 				IsCarriedOver: !shouldAppear && habit.CarryOver,
 			})
diff --git a/internal/application/queries/get_todays_habits_test.go b/internal/application/queries/get_todays_habits_test.go
index f8d5e1b..2e0c865 100644
--- a/internal/application/queries/get_todays_habits_test.go
+++ b/internal/application/queries/get_todays_habits_test.go
@@ -76,7 +76,7 @@ func (m *mockEntryRepo) Delete(ctx context.Context, id string) error {
 }
 
 func TestGetTodaysHabitsHandler_DailyHabitNoEntries(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	habitRepo := &mockHabitRepo{habits: []*entities.Habit{habit}}
@@ -110,7 +110,7 @@ func TestGetTodaysHabitsHandler_DailyHabitNoEntries(t *testing.T) {
 }
 
 func TestGetTodaysHabitsHandler_DailyHabitAlreadyCompleted(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit.ID = "habit-1"
 
 	targetDate := time.Date(2025, 1, 15, 0, 0, 0, 0, time.UTC)
@@ -139,7 +139,7 @@ func TestGetTodaysHabitsHandler_DailyHabitAlreadyCompleted(t *testing.T) {
 }
 
 func TestGetTodaysHabitsHandler_WeeklyHabitOnCorrectDay(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Gym", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false)
+	habit := entities.NewHabit("user-123", "Gym", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false, false)
 	habit.ID = "habit-1"
 	habit.SpecificDays = []int{1, 3, 5}
 
@@ -168,7 +168,7 @@ func TestGetTodaysHabitsHandler_WeeklyHabitOnCorrectDay(t *testing.T) {
 }
 
 func TestGetTodaysHabitsHandler_WeeklyHabitOnWrongDay(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Gym", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false)
+	habit := entities.NewHabit("user-123", "Gym", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false, false)
 	habit.ID = "habit-1"
 	habit.SpecificDays = []int{1, 3, 5}
 
@@ -197,7 +197,7 @@ func TestGetTodaysHabitsHandler_WeeklyHabitOnWrongDay(t *testing.T) {
 }
 
 func TestGetTodaysHabitsHandler_CarryOverEnabled(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Gym", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, true)
+	habit := entities.NewHabit("user-123", "Gym", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, true, false)
 	habit.ID = "habit-1"
 	habit.SpecificDays = []int{1}
 
@@ -230,7 +230,7 @@ func TestGetTodaysHabitsHandler_CarryOverEnabled(t *testing.T) {
 }
 
 func TestGetTodaysHabitsHandler_CarryOverDisabled(t *testing.T) {
-	habit := entities.NewHabit("user-123", "Gym", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false)
+	habit := entities.NewHabit("user-123", "Gym", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false, false)
 	habit.ID = "habit-1"
 	habit.SpecificDays = []int{1}
 
diff --git a/internal/application/queries/get_user_habits.go b/internal/application/queries/get_user_habits.go
index fc95104..b4930d7 100644
--- a/internal/application/queries/get_user_habits.go
+++ b/internal/application/queries/get_user_habits.go
@@ -14,6 +14,7 @@ type HabitDTO struct {
 	Frequency    value_objects.Frequency
 	TargetValue  *float64
 	CarryOver    bool
+	IsNegative   bool
 	SpecificDays []int
 }
 
@@ -46,6 +47,7 @@ func (h *GetUserHabitsHandler) Handle(ctx context.Context, query GetUserHabitsQu
 			Frequency:    habit.Frequency,
 			TargetValue:  habit.TargetValue,
 			CarryOver:    habit.CarryOver,
+			IsNegative:   habit.IsNegative,
 			SpecificDays: habit.SpecificDays,
 		})
 	}
diff --git a/internal/application/queries/get_user_habits_test.go b/internal/application/queries/get_user_habits_test.go
index 39b5db8..49684ba 100644
--- a/internal/application/queries/get_user_habits_test.go
+++ b/internal/application/queries/get_user_habits_test.go
@@ -9,10 +9,10 @@ import (
 )
 
 func TestGetUserHabitsHandler_ReturnsAllActiveHabits(t *testing.T) {
-	habit1 := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit1 := entities.NewHabit("user-123", "Exercise", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 	habit1.ID = "habit-1"
 
-	habit2 := entities.NewHabit("user-123", "Read", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false)
+	habit2 := entities.NewHabit("user-123", "Read", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false, false)
 	habit2.ID = "habit-2"
 
 	habitRepo := &mockHabitRepo{habits: []*entities.Habit{habit1, habit2}}
@@ -64,7 +64,7 @@ func TestGetUserHabitsHandler_ReturnsEmptyListForUserWithNoHabits(t *testing.T)
 
 func TestGetUserHabitsHandler_IncludesAllHabitFields(t *testing.T) {
 	targetValue := 5.0
-	habit := entities.NewHabit("user-123", "Drink Water", value_objects.HabitTypeValue, value_objects.FrequencyDaily, true)
+	habit := entities.NewHabit("user-123", "Drink Water", value_objects.HabitTypeValue, value_objects.FrequencyDaily, true, false)
 	habit.ID = "habit-1"
 	habit.TargetValue = &targetValue
 
diff --git a/internal/domain/entities/habit.go b/internal/domain/entities/habit.go
index 7fcb7a1..0b41143 100644
--- a/internal/domain/entities/habit.go
+++ b/internal/domain/entities/habit.go
@@ -16,6 +16,7 @@ type Habit struct {
 	SpecificDays  []int
 	SpecificDates []int
 	CarryOver     bool
+	IsNegative    bool
 	TargetValue   *float64
 	CreatedAt     time.Time
 	ArchivedAt    *time.Time
@@ -27,14 +28,16 @@ func NewHabit(
 	habitType value_objects.HabitType,
 	frequency value_objects.Frequency,
 	carryOver bool,
+	isNegative bool,
 ) *Habit {
 	return &Habit{
-		UserID:    userID,
-		Name:      name,
-		Type:      habitType,
-		Frequency: frequency,
-		CarryOver: carryOver,
-		CreatedAt: time.Now(),
+		UserID:     userID,
+		Name:       name,
+		Type:       habitType,
+		Frequency:  frequency,
+		CarryOver:  carryOver,
+		IsNegative: isNegative,
+		CreatedAt:  time.Now(),
 	}
 }
 
diff --git a/internal/domain/entities/habit_test.go b/internal/domain/entities/habit_test.go
index 44226d2..87e80af 100644
--- a/internal/domain/entities/habit_test.go
+++ b/internal/domain/entities/habit_test.go
@@ -13,8 +13,9 @@ func TestNewHabit(t *testing.T) {
 	habitType := value_objects.HabitTypeBoolean
 	frequency := value_objects.FrequencyDaily
 	carryOver := false
+	isNegative := false
 
-	habit := NewHabit(userID, name, habitType, frequency, carryOver)
+	habit := NewHabit(userID, name, habitType, frequency, carryOver, isNegative)
 
 	if habit.UserID != userID {
 		t.Errorf("Expected UserID %s, got %s", userID, habit.UserID)
@@ -46,7 +47,7 @@ func TestNewHabit(t *testing.T) {
 }
 
 func TestHabit_Archive(t *testing.T) {
-	habit := NewHabit("user-123", "Test Habit", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := NewHabit("user-123", "Test Habit", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 
 	if habit.ArchivedAt != nil {
 		t.Error("New habit should not be archived")
@@ -64,7 +65,7 @@ func TestHabit_Archive(t *testing.T) {
 }
 
 func TestHabit_IsActive(t *testing.T) {
-	habit := NewHabit("user-123", "Test Habit", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit := NewHabit("user-123", "Test Habit", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 
 	if !habit.IsActive() {
 		t.Error("New habit should be active")
@@ -78,7 +79,7 @@ func TestHabit_IsActive(t *testing.T) {
 }
 
 func TestHabit_WithSpecificDays(t *testing.T) {
-	habit := NewHabit("user-123", "Workout", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false)
+	habit := NewHabit("user-123", "Workout", value_objects.HabitTypeBoolean, value_objects.FrequencyWeekly, false, false)
 	habit.SpecificDays = []int{1, 3, 5} // Monday, Wednesday, Friday
 
 	if len(habit.SpecificDays) != 3 {
@@ -91,7 +92,7 @@ func TestHabit_WithSpecificDays(t *testing.T) {
 }
 
 func TestHabit_WithTargetValue(t *testing.T) {
-	habit := NewHabit("user-123", "Drink Water", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false)
+	habit := NewHabit("user-123", "Drink Water", value_objects.HabitTypeCounter, value_objects.FrequencyDaily, false, false)
 	targetValue := 8.0
 	habit.TargetValue = &targetValue
 
diff --git a/internal/infrastructure/http/dto.go b/internal/infrastructure/http/dto.go
index eb6b397..4bb1583 100644
--- a/internal/infrastructure/http/dto.go
+++ b/internal/infrastructure/http/dto.go
@@ -14,6 +14,7 @@ type CreateHabitRequest struct {
 	SpecificDays  []int                    `json:"specific_days,omitempty"`
 	SpecificDates []int                    `json:"specific_dates,omitempty"`
 	CarryOver     bool                     `json:"carry_over"`
+	IsNegative    bool                     `json:"is_negative"`
 	TargetValue   *float64                 `json:"target_value,omitempty"`
 }
 
@@ -36,6 +37,7 @@ type HabitResponse struct {
 	SpecificDays  []int                    `json:"specific_days,omitempty"`
 	SpecificDates []int                    `json:"specific_dates,omitempty"`
 	CarryOver     bool                     `json:"carry_over"`
+	IsNegative    bool                     `json:"is_negative"`
 	TargetValue   *float64                 `json:"target_value,omitempty"`
 	CreatedAt     time.Time                `json:"created_at"`
 	ArchivedAt    *time.Time               `json:"archived_at,omitempty"`
@@ -51,6 +53,7 @@ type TodaysHabitResponse struct {
 	Name          string                  `json:"name"`
 	Type          value_objects.HabitType `json:"type"`
 	TargetValue   *float64                `json:"target_value,omitempty"`
+	IsNegative    bool                    `json:"is_negative"`
 	ScheduledDate time.Time               `json:"scheduled_date"`
 	IsCarriedOver bool                    `json:"is_carried_over"`
 }
@@ -63,6 +66,7 @@ type UserHabitResponse struct {
 	SpecificDays []int                    `json:"specific_days,omitempty"`
 	TargetValue  *float64                 `json:"target_value,omitempty"`
 	CarryOver    bool                     `json:"carry_over"`
+	IsNegative   bool                     `json:"is_negative"`
 }
 
 type HabitEntryResponse struct {
diff --git a/internal/infrastructure/http/habit_handlers.go b/internal/infrastructure/http/habit_handlers.go
index 1259c0f..6b22798 100644
--- a/internal/infrastructure/http/habit_handlers.go
+++ b/internal/infrastructure/http/habit_handlers.go
@@ -84,6 +84,7 @@ func (h *HabitHandlers) CreateHabit(w http.ResponseWriter, r *http.Request) {
 		SpecificDays:  req.SpecificDays,
 		SpecificDates: req.SpecificDates,
 		CarryOver:     req.CarryOver,
+		IsNegative:    req.IsNegative,
 		TargetValue:   req.TargetValue,
 	}
 
@@ -137,6 +138,7 @@ func (h *HabitHandlers) GetUserHabits(w http.ResponseWriter, r *http.Request) {
 			SpecificDays: habit.SpecificDays,
 			TargetValue:  habit.TargetValue,
 			CarryOver:    habit.CarryOver,
+			IsNegative:   habit.IsNegative,
 		}
 	}
 
@@ -192,6 +194,7 @@ func (h *HabitHandlers) GetHabitByID(w http.ResponseWriter, r *http.Request) {
 		SpecificDays: habit.SpecificDays,
 		TargetValue:  habit.TargetValue,
 		CarryOver:    habit.CarryOver,
+		IsNegative:   habit.IsNegative,
 	}
 
 	respondJSON(w, http.StatusOK, response)
@@ -464,6 +467,7 @@ func (h *HabitHandlers) GetTodaysHabits(w http.ResponseWriter, r *http.Request)
 			Name:          habit.Name,
 			Type:          habit.Type,
 			TargetValue:   habit.TargetValue,
+			IsNegative:    habit.IsNegative,
 			ScheduledDate: habit.ScheduledDate,
 			IsCarriedOver: habit.IsCarriedOver,
 		}
diff --git a/internal/infrastructure/persistence/sqlite/habit_repository.go b/internal/infrastructure/persistence/sqlite/habit_repository.go
index 8e978a3..2bbe89a 100644
--- a/internal/infrastructure/persistence/sqlite/habit_repository.go
+++ b/internal/infrastructure/persistence/sqlite/habit_repository.go
@@ -29,8 +29,8 @@ func (r *HabitRepository) Create(ctx context.Context, habit *entities.Habit) err
 	query := `
 		INSERT INTO habits (
 			id, user_id, name, description, type, frequency,
-			specific_days, specific_dates, carry_over, target_value, created_at
-		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+			specific_days, specific_dates, carry_over, is_negative, target_value, created_at
+		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
 	`
 
 	_, err := r.db.ExecContext(ctx, query,
@@ -43,6 +43,7 @@ func (r *HabitRepository) Create(ctx context.Context, habit *entities.Habit) err
 		specificDays,
 		specificDates,
 		habit.CarryOver,
+		habit.IsNegative,
 		habit.TargetValue,
 		habit.CreatedAt,
 	)
@@ -57,7 +58,7 @@ func (r *HabitRepository) Create(ctx context.Context, habit *entities.Habit) err
 func (r *HabitRepository) FindByID(ctx context.Context, id string) (*entities.Habit, error) {
 	query := `
 		SELECT id, user_id, name, description, type, frequency,
-			   specific_days, specific_dates, carry_over, target_value,
+			   specific_days, specific_dates, carry_over, is_negative, target_value,
 			   created_at, archived_at
 		FROM habits
 		WHERE id = ?
@@ -80,6 +81,7 @@ func (r *HabitRepository) FindByID(ctx context.Context, id string) (*entities.Ha
 		&specificDays,
 		&specificDates,
 		&habit.CarryOver,
+		&habit.IsNegative,
 		&habit.TargetValue,
 		&habit.CreatedAt,
 		&archivedAt,
@@ -108,7 +110,7 @@ func (r *HabitRepository) FindByID(ctx context.Context, id string) (*entities.Ha
 func (r *HabitRepository) FindActiveByUserID(ctx context.Context, userID string) ([]*entities.Habit, error) {
 	query := `
 		SELECT id, user_id, name, description, type, frequency,
-			   specific_days, specific_dates, carry_over, target_value,
+			   specific_days, specific_dates, carry_over, is_negative, target_value,
 			   created_at, archived_at
 		FROM habits
 		WHERE user_id = ? AND archived_at IS NULL
@@ -131,7 +133,7 @@ func (r *HabitRepository) Update(ctx context.Context, habit *entities.Habit) err
 	query := `
 		UPDATE habits
 		SET name = ?, description = ?, type = ?, frequency = ?,
-			specific_days = ?, specific_dates = ?, carry_over = ?,
+			specific_days = ?, specific_dates = ?, carry_over = ?, is_negative = ?,
 			target_value = ?, archived_at = ?
 		WHERE id = ?
 	`
@@ -144,6 +146,7 @@ func (r *HabitRepository) Update(ctx context.Context, habit *entities.Habit) err
 		specificDays,
 		specificDates,
 		habit.CarryOver,
+		habit.IsNegative,
 		habit.TargetValue,
 		habit.ArchivedAt,
 		habit.ID,
@@ -182,6 +185,7 @@ func (r *HabitRepository) scanHabits(rows *sql.Rows) ([]*entities.Habit, error)
 			&specificDays,
 			&specificDates,
 			&habit.CarryOver,
+			&habit.IsNegative,
 			&habit.TargetValue,
 			&habit.CreatedAt,
 			&archivedAt,
@@ -210,7 +214,7 @@ func (r *HabitRepository) scanHabits(rows *sql.Rows) ([]*entities.Habit, error)
 func (r *HabitRepository) FindByUserID(ctx context.Context, userID string) ([]*entities.Habit, error) {
 	query := `
 		SELECT id, user_id, name, description, type, frequency,
-			   specific_days, specific_dates, carry_over, target_value,
+			   specific_days, specific_dates, carry_over, is_negative, target_value,
 			   created_at, archived_at
 		FROM habits
 		WHERE user_id = ?
diff --git a/internal/infrastructure/persistence/sqlite/habit_repository_test.go b/internal/infrastructure/persistence/sqlite/habit_repository_test.go
index 7f57688..72f0edb 100644
--- a/internal/infrastructure/persistence/sqlite/habit_repository_test.go
+++ b/internal/infrastructure/persistence/sqlite/habit_repository_test.go
@@ -130,9 +130,9 @@ func TestHabitRepositoryFindActiveByUserID(t *testing.T) {
 
 	userID := "user-789"
 
-	habit1 := entities.NewHabit(userID, "Habit 1", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
-	habit2 := entities.NewHabit(userID, "Habit 2", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
-	habit3 := entities.NewHabit(userID, "Habit 3", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false)
+	habit1 := entities.NewHabit(userID, "Habit 1", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
+	habit2 := entities.NewHabit(userID, "Habit 2", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
+	habit3 := entities.NewHabit(userID, "Habit 3", value_objects.HabitTypeBoolean, value_objects.FrequencyDaily, false, false)
 
 	repo.Create(ctx, habit1)
 	repo.Create(ctx, habit2)
diff --git a/internal/infrastructure/persistence/sqlite/migrations.go b/internal/infrastructure/persistence/sqlite/migrations.go
index e8b1353..ce7e4a5 100644
--- a/internal/infrastructure/persistence/sqlite/migrations.go
+++ b/internal/infrastructure/persistence/sqlite/migrations.go
@@ -42,6 +42,7 @@ CREATE TABLE IF NOT EXISTS habits (
 	specific_days TEXT,
 	specific_dates TEXT,
 	carry_over BOOLEAN DEFAULT 0,
+	is_negative BOOLEAN DEFAULT 0,
 	target_value REAL,
 	created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
 	archived_at DATETIME,