diff --git a/comments.go b/comments.go
index 53a1a0f..72f3b3f 100644
--- a/comments.go
+++ b/comments.go
@@ -42,7 +42,7 @@ func (c *Client) CreateComment(ctx context.Context, taskID, userID int, content
 		"content": content,
 	}
 
-	var commentID int
+	var commentID IntOrFalse
 	if err := c.call(ctx, "createComment", params, &commentID); err != nil {
 		return nil, fmt.Errorf("createComment: %w", err)
 	}
@@ -52,7 +52,7 @@ func (c *Client) CreateComment(ctx context.Context, taskID, userID int, content
 	}
 
 	// Fetch the created comment to return full details
-	return c.GetComment(ctx, commentID)
+	return c.GetComment(ctx, int(commentID))
 }
 
 // UpdateComment updates the content of a comment.
diff --git a/files.go b/files.go
index 929db4e..5ed3d8f 100644
--- a/files.go
+++ b/files.go
@@ -29,7 +29,7 @@ func (c *Client) CreateTaskFile(ctx context.Context, projectID, taskID int, file
 		"blob":       base64.StdEncoding.EncodeToString(content),
 	}
 
-	var result int
+	var result IntOrFalse
 	if err := c.call(ctx, "createTaskFile", params, &result); err != nil {
 		return 0, fmt.Errorf("createTaskFile: %w", err)
 	}
@@ -38,7 +38,7 @@ func (c *Client) CreateTaskFile(ctx context.Context, projectID, taskID int, file
 		return 0, fmt.Errorf("createTaskFile: failed to upload file")
 	}
 
-	return result, nil
+	return int(result), nil
 }
 
 // DownloadTaskFile downloads a file's content by its ID.
diff --git a/links.go b/links.go
index 1d26007..dc1e65c 100644
--- a/links.go
+++ b/links.go
@@ -27,7 +27,7 @@ func (c *Client) CreateTaskLink(ctx context.Context, taskID, oppositeTaskID, lin
 		"link_id":          linkID,
 	}
 
-	var result int
+	var result IntOrFalse
 	if err := c.call(ctx, "createTaskLink", params, &result); err != nil {
 		return 0, fmt.Errorf("createTaskLink: %w", err)
 	}
@@ -36,7 +36,7 @@ func (c *Client) CreateTaskLink(ctx context.Context, taskID, oppositeTaskID, lin
 		return 0, fmt.Errorf("createTaskLink: failed to create link")
 	}
 
-	return result, nil
+	return int(result), nil
 }
 
 // RemoveTaskLink deletes a task link.
diff --git a/tags.go b/tags.go
index 4f40b20..de5b21e 100644
--- a/tags.go
+++ b/tags.go
@@ -75,11 +75,11 @@ func (c *Client) CreateTag(ctx context.Context, projectID int, name, colorID str
 		params["color_id"] = colorID
 	}
 
-	var result int
+	var result IntOrFalse
 	if err := c.call(ctx, "createTag", params, &result); err != nil {
 		return 0, fmt.Errorf("createTag: %w", err)
 	}
-	return result, nil
+	return int(result), nil
 }
 
 // UpdateTag updates an existing tag's name and/or color.
diff --git a/tasks.go b/tasks.go
index 4d8211c..866e444 100644
--- a/tasks.go
+++ b/tasks.go
@@ -41,7 +41,7 @@ func (c *Client) GetAllTasks(ctx context.Context, projectID int, status TaskStat
 
 // CreateTask creates a new task and returns the created task.
 func (c *Client) CreateTask(ctx context.Context, req CreateTaskRequest) (*Task, error) {
-	var taskID int
+	var taskID IntOrFalse
 	if err := c.call(ctx, "createTask", req, &taskID); err != nil {
 		return nil, fmt.Errorf("createTask: %w", err)
 	}
@@ -51,7 +51,7 @@ func (c *Client) CreateTask(ctx context.Context, req CreateTaskRequest) (*Task,
 	}
 
 	// Fetch the created task to return full details
-	return c.GetTask(ctx, taskID)
+	return c.GetTask(ctx, int(taskID))
 }
 
 // UpdateTask updates an existing task.
diff --git a/types.go b/types.go
index 3e0160d..c729dae 100644
--- a/types.go
+++ b/types.go
@@ -2,6 +2,7 @@ package kanboard
 
 import (
 	"encoding/json"
+	"fmt"
 	"strconv"
 )
 
@@ -105,6 +106,33 @@ func (i *StringInt64) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
+// IntOrFalse is an int that can be unmarshaled from a JSON int or false.
+// Kanboard API returns false on failure, int (ID) on success for create operations.
+type IntOrFalse int
+
+// UnmarshalJSON implements json.Unmarshaler.
+func (i *IntOrFalse) UnmarshalJSON(data []byte) error {
+	// Try as int first (success case)
+	var n int
+	if err := json.Unmarshal(data, &n); err == nil {
+		*i = IntOrFalse(n)
+		return nil
+	}
+
+	// Try as bool (failure case: false)
+	var b bool
+	if err := json.Unmarshal(data, &b); err == nil {
+		if b {
+			*i = 1 // true shouldn't happen, but handle it
+		} else {
+			*i = 0
+		}
+		return nil
+	}
+
+	return fmt.Errorf("cannot unmarshal %s into IntOrFalse", data)
+}
+
 // Project represents a Kanboard project (board).
 type Project struct {
 	ID                  StringInt  `json:"id"`
diff --git a/types_test.go b/types_test.go
index 6b3e9e3..1bc1d73 100644
--- a/types_test.go
+++ b/types_test.go
@@ -97,6 +97,31 @@ func TestStringInt64_UnmarshalJSON(t *testing.T) {
 	}
 }
 
+func TestIntOrFalse_UnmarshalJSON(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected int
+	}{
+		{"int value", `42`, 42},
+		{"int zero", `0`, 0},
+		{"false", `false`, 0},
+		{"true", `true`, 1},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var i IntOrFalse
+			if err := json.Unmarshal([]byte(tt.input), &i); err != nil {
+				t.Fatalf("unmarshal error: %v", err)
+			}
+			if int(i) != tt.expected {
+				t.Errorf("expected %v, got %v", tt.expected, i)
+			}
+		})
+	}
+}
+
 func TestProject_UnmarshalJSON(t *testing.T) {
 	jsonData := `{
 		"id": "1",