diff --git a/go.sum b/go.sum
index 41392f4..c720d0e 100644
--- a/go.sum
+++ b/go.sum
@@ -13,6 +13,8 @@ github.com/alecthomas/chroma/v2 v2.14.0 h1:R3+wzpnUArGcQz7fCETQBzO5n9IMNi13iIs46
 github.com/alecthomas/chroma/v2 v2.14.0/go.mod h1:QolEbTfmUHIMVpBqxeDnNBj2uoeI4EbYP4i6n68SG4I=
 github.com/alecthomas/repr v0.4.0 h1:GhI2A8MACjfegCPVq9f1FLvIBS+DrQ2KQBFZP1iFzXc=
 github.com/alecthomas/repr v0.4.0/go.mod h1:Fr0507jx4eOXV7AlPV6AVZLYrLIuIeSOWtW57eE/O/4=
+github.com/analog-substance/util v1.0.3 h1:qMlqWtJDvrREv1ZKkJ0qvDFZ+VwpwTeN1UBLc5h0bP8=
+github.com/analog-substance/util v1.0.3/go.mod h1:J0ESO2Rd8bhJgEdn/U7CIlNGR72GaH7FcMJXBDqfKsk=
 github.com/apparentlymart/go-textseg/v15 v15.0.0 h1:uYvfpb3DyLSCGWnctWKGj857c6ew1u1fNQOlOtuGxQY=
 github.com/apparentlymart/go-textseg/v15 v15.0.0/go.mod h1:K8XmNZdhEBkdlyDdvbmmsvpAG721bKi0joRfFdHIWJ4=
 github.com/atotto/clipboard v0.1.4 h1:EH0zSVneZPSuFR11BlR9YppQTVDbh5+16AmcJi4g1z4=
diff --git a/pkg/cmd/project_add_machine.go b/pkg/cmd/project_add_machine.go
index ea98dcf..8c2491a 100644
--- a/pkg/cmd/project_add_machine.go
+++ b/pkg/cmd/project_add_machine.go
@@ -17,6 +17,7 @@ var projectAddCmd = &cobra.Command{
 		vmName, _ := cmd.Flags().GetString("name")
 		serviceProvider, _ := cmd.Flags().GetString("service")
 		vmImage, _ := cmd.Flags().GetString("image")
+		noApply, _ := cmd.Flags().GetBool("no-apply")
 
 		project, err := carbonObj.GetProject(projectName)
 		if err != nil {
@@ -27,7 +28,7 @@ var projectAddCmd = &cobra.Command{
 			Name:     vmName,
 			Provider: serviceProvider,
 			Image:    vmImage,
-		})
+		}, noApply)
 		if err != nil {
 			fmt.Printf("Failed to save project: %s\n", err)
 		}
@@ -38,6 +39,7 @@ func init() {
 	projectCmd.AddCommand(projectAddCmd)
 	projectAddCmd.PersistentFlags().StringP("name", "n", "", "Name of the VM to add.")
 	projectAddCmd.PersistentFlags().StringP("image", "i", "", "Name of the image to use.")
+	projectAddCmd.PersistentFlags().BoolP("no-apply", "N", false, "Do not run terraform apply.")
 
 	addServiceProviderFlag(projectAddCmd)
 
diff --git a/pkg/models/project.go b/pkg/models/project.go
index bd544c3..9ab2ed1 100644
--- a/pkg/models/project.go
+++ b/pkg/models/project.go
@@ -49,11 +49,18 @@ func (d *Project) TerraformApply() error {
 	return builder.Cmd(terraformPath, args...).Dir(d.buildPath).Interactive().Run()
 }
 
-func (d *Project) AddMachine(machine *types.ProjectMachine) error {
+func (d *Project) AddMachine(machine *types.ProjectMachine, noApply bool) error {
 	_, err := d.GetConfig()
 	if err != nil {
 		return err
 	}
+
+	for _, existingMachine := range d.config.Machines {
+		if existingMachine.Name == machine.Name {
+			return fmt.Errorf("machine '%s' already exists", machine.Name)
+		}
+	}
+
 	d.config.Machines = append(d.config.Machines, machine)
 	err = d.SaveConfig()
 	if err != nil {
diff --git a/pkg/types/project.go b/pkg/types/project.go
index 2c10205..28a6849 100644
--- a/pkg/types/project.go
+++ b/pkg/types/project.go
@@ -3,5 +3,5 @@ package types
 type Project interface {
 	Name() string
 	TerraformApply() error
-	AddMachine(machine *ProjectMachine) error
+	AddMachine(machine *ProjectMachine, noApply bool) error
 }