Why do dynamically added servers not get checked?

I am setting up HAProxy for a simple backend server. This is my haproxy.cfg file:

global  user haproxy  group haproxy  stats socket /var/run/haproxy.sock mode 660 level admin expose-fd listeners  daemonfrontend webapp  mode http  bind *:80  default_backend webserversbackend webservers  mode http  balance roundrobin  server s1 web1:5000 check  server s2 web2:5000 checklisten stats  bind *:9999  mode http  stats enable  stats uri /stats  stats hide-version

Now, after sending requests to port :80 and starting my HAProxy container I pull up the HAProxy stats page and see the following:

Notice how, even though I did not explicitly defined it in the haproxy.cfg file, layer 4 health checks are being performed on these servers. Now I use the Runtime API to add a server, explicitly:

echo "add server webservers/s3 10.89.1.47:5000 check" | socat stdio /var/run/haproxy.sock

and also switch the state to ready,

echo "set server webservers/s3 state ready" | socat stdio /var/run/haproxy.sock

Then I see the following in the HAProxy stats page:

The requests are now being load balanced across the new server, which is great. However, I noticed that its status is 'no check', indicating that no health checks are being performed on the new server. I'm confident that my added server is up and running, and handling requests effectively. Nevertheless, I would like it to have the same status as the default servers, which undergo health checks. Can you please advise why there are no health checks being performed on my new server, while the default servers are being checked?

I already tried adding the option tcp-check but this did not work. Also, as I understand, I should not set option tcp-check if my mode is mode http.