diff --git a/d2plugin/serve.go b/d2plugin/serve.go
index cf857b3ee..2e8da78f0 100644
--- a/d2plugin/serve.go
+++ b/d2plugin/serve.go
@@ -21,6 +21,13 @@ import (
 // Also see execPlugin in exec.go for the d2 binary plugin protocol.
 func Serve(p Plugin) xmain.RunFunc {
 	return func(ctx context.Context, ms *xmain.State) (err error) {
+		fs, err := p.Flags(ctx)
+		if err != nil {
+			return err
+		}
+		for _, f := range fs {
+			f.AddToOpts(ms.Opts)
+		}
 		err = ms.Opts.Flags.Parse(ms.Opts.Args)
 		if !errors.Is(err, pflag.ErrHelp) && err != nil {
 			return xmain.UsageErrorf("failed to parse flags: %v", err)