diff --git a/cmd/banger/main.go b/cmd/banger/main.go
index bee0caa..0719e11 100644
--- a/cmd/banger/main.go
+++ b/cmd/banger/main.go
@@ -17,9 +17,9 @@ func main() {
 
 	cmd := cli.NewBangerCommand()
 	if err := cmd.ExecuteContext(ctx); err != nil {
-		var exitErr interface{ ExitCode() int }
+		var exitErr cli.ExitCodeError
 		if errors.As(err, &exitErr) {
-			os.Exit(exitErr.ExitCode())
+			os.Exit(exitErr.Code)
 		}
 		fmt.Fprintf(os.Stderr, "banger: %v\n", err)
 		os.Exit(1)
diff --git a/internal/cli/banger.go b/internal/cli/banger.go
index 78b38c2..3ec07a7 100644
--- a/internal/cli/banger.go
+++ b/internal/cli/banger.go
@@ -2810,20 +2810,19 @@ func splitVMRunArgs(cmd *cobra.Command, args []string) (pathArgs, commandArgs []
 	return args[:dash], args[dash:]
 }
 
-// exitCodeError wraps a remote command's exit status so the CLI's main()
-// can propagate it verbatim. Setup errors and other failures stay as
-// regular errors.
-type exitCodeError struct {
+// ExitCodeError wraps a remote command's exit status so the CLI's main()
+// can propagate it verbatim. Only errors explicitly wrapped in this
+// type get forwarded as process exit codes — plain *exec.ExitError
+// values (from unrelated subprocesses like mkfs.ext4) must still
+// surface as regular errors so the user sees a message.
+type ExitCodeError struct {
 	Code int
 }
 
-func (e exitCodeError) Error() string {
+func (e ExitCodeError) Error() string {
 	return fmt.Sprintf("exit status %d", e.Code)
 }
 
-// ExitCode exposes the code for callers using errors.As.
-func (e exitCodeError) ExitCode() int { return e.Code }
-
 func runVMRun(ctx context.Context, socketPath string, cfg model.DaemonConfig, stdin io.Reader, stdout, stderr io.Writer, params api.VMCreateParams, spec *vmRunRepoSpec, command []string) error {
 	progress := newVMRunProgressRenderer(stderr)
 	vm, err := runVMCreate(ctx, socketPath, stderr, params)
@@ -2871,7 +2870,7 @@ func runVMRun(ctx context.Context, socketPath string, cfg model.DaemonConfig, st
 		if err := sshExecFunc(ctx, stdin, stdout, stderr, sshArgs); err != nil {
 			var exitErr *exec.ExitError
 			if errors.As(err, &exitErr) {
-				return exitCodeError{Code: exitErr.ExitCode()}
+				return ExitCodeError{Code: exitErr.ExitCode()}
 			}
 			return err
 		}
diff --git a/internal/cli/cli_test.go b/internal/cli/cli_test.go
index 9ce8947..ae5b0f3 100644
--- a/internal/cli/cli_test.go
+++ b/internal/cli/cli_test.go
@@ -1675,9 +1675,9 @@ func TestRunVMRunCommandModePropagatesExitCode(t *testing.T) {
 		nil,
 		[]string{"false"},
 	)
-	var exitErr exitCodeError
+	var exitErr ExitCodeError
 	if !errors.As(err, &exitErr) || exitErr.Code != 7 {
-		t.Fatalf("runVMRun error = %v, want exitCodeError{7}", err)
+		t.Fatalf("runVMRun error = %v, want ExitCodeError{7}", err)
 	}
 	if len(sshArgsSeen) == 0 || sshArgsSeen[len(sshArgsSeen)-1] != "false" {
 		t.Fatalf("sshArgsSeen = %v, want trailing command 'false'", sshArgsSeen)