diff --git a/plan/command/add.go b/plan/command/add.go
index 3f483a9..af99947 100644
--- a/plan/command/add.go
+++ b/plan/command/add.go
@@ -1,6 +1,7 @@
 package command
 
 import (
+	"errors"
 	"fmt"
 	"time"
 
@@ -9,19 +10,25 @@ import (
 	"go-mod.ewintr.nl/planner/plan/storage"
 )
 
+var (
+	ErrInvalidArg = errors.New("invalid argument")
+)
+
 var AddCmd = &cli.Command{
 	Name:  "add",
 	Usage: "Add a new event",
 	Flags: []cli.Flag{
 		&cli.StringFlag{
-			Name:    "name",
-			Aliases: []string{"n"},
-			Usage:   "The event that will happen",
+			Name:     "name",
+			Aliases:  []string{"n"},
+			Usage:    "The event that will happen",
+			Required: true,
 		},
 		&cli.StringFlag{
-			Name:    "on",
-			Aliases: []string{"o"},
-			Usage:   "The date, in YYYY-MM-DD format",
+			Name:     "on",
+			Aliases:  []string{"o"},
+			Usage:    "The date, in YYYY-MM-DD format",
+			Required: true,
 		},
 		&cli.StringFlag{
 			Name:    "at",
@@ -37,29 +44,49 @@ var AddCmd = &cli.Command{
 }
 
 func NewAddCmd(repo storage.EventRepo) *cli.Command {
-	AddCmd.Action = NewAddAction(repo)
+	AddCmd.Action = func(cCtx *cli.Context) error {
+		return Add(cCtx.String("name"), cCtx.String("on"), cCtx.String("at"), cCtx.String("for"), repo)
+	}
 	return AddCmd
 }
 
-func NewAddAction(repo storage.EventRepo) func(*cli.Context) error {
-	return func(cCtx *cli.Context) error {
-		desc := cCtx.String("name")
-		date, err := time.Parse("2006-01-02", cCtx.String("date"))
-		if err != nil {
-			return fmt.Errorf("could not parse date: %v", err)
-		}
-
-		one := item.Event{
-			ID: "a",
-			EventBody: item.EventBody{
-				Title: desc,
-				Start: date,
-			},
-		}
-		if err := repo.Store(one); err != nil {
-			return fmt.Errorf("could not store event: %v", err)
-		}
-
-		return nil
+func Add(nameStr, onStr, atStr, frStr string, repo storage.EventRepo) error {
+	if nameStr == "" {
+		return fmt.Errorf("%w: name is required", ErrInvalidArg)
 	}
+	if onStr == "" {
+		return fmt.Errorf("%w: date is required", ErrInvalidArg)
+	}
+
+	startFormat := "2006-01-02"
+	startStr := onStr
+	if atStr != "" {
+		startFormat = fmt.Sprintf("%s HH:MM", startFormat)
+		startStr = fmt.Sprintf("%s %s", startStr, atStr)
+	}
+	start, err := time.Parse(startFormat, startStr)
+	if err != nil {
+		return fmt.Errorf("%w: could not parse start time and date: %v", ErrInvalidArg, err)
+	}
+
+	e := item.Event{
+		ID: "a",
+		EventBody: item.EventBody{
+			Title: nameStr,
+			Start: start,
+		},
+	}
+
+	if frStr != "" {
+		fr, err := time.ParseDuration(frStr)
+		if err != nil {
+			return fmt.Errorf("%w: could not parse time: %s", ErrInvalidArg, err)
+		}
+		e.Duration = fr
+	}
+	if err := repo.Store(e); err != nil {
+		return fmt.Errorf("could not store event: %v", err)
+	}
+
+	return nil
 }
diff --git a/plan/command/add_test.go b/plan/command/add_test.go
new file mode 100644
index 0000000..d67ee54
--- /dev/null
+++ b/plan/command/add_test.go
@@ -0,0 +1,10 @@
+package command_test
+
+func TestAdd(t *testing.T) {
+  t.Parallel()
+
+  for _, tc := range []struct{
+    name string
+     
+  } 
+}