diff --git a/src/reynir_www.ml b/src/reynir_www.ml
index ccb420b..636240a 100644
--- a/src/reynir_www.ml
+++ b/src/reynir_www.ml
@@ -18,8 +18,7 @@ let program ~target =
 let local_build _quiet target =
   Yocaml_unix.execute (program ~target:(Fpath.to_string target))
 
-let watch quiet target potential_port =
-  let port = Option.value ~default:default_port potential_port in
+let watch quiet target port =
   let () = local_build quiet target in
   let target = Fpath.to_string target in
   let server = Yocaml_unix.serve ~filepath:target ~port (program ~target) in
@@ -92,7 +91,7 @@ let watch_cmd =
   let port_arg =
     let doc = "The port" in
     let arg = Arg.info ~doc [ "port"; "P"; "p" ] in
-    Arg.(value & opt (some int) None & arg)
+    Arg.(value & opt int default_port & arg)
   in
   let info = Cmd.info "watch" ~version ~doc ~exits ~man in
   Cmd.v info Term.(const watch $ setup_logs $ path_arg $ port_arg)