saudi business visit visa details

From date of entry you have to exit re entry within 30 days

I am on a business Visa in Riyadh. The validity is 90 days and maximum stay of 30 days. multiple entry What is the right way to get an extension on my 30-day business visit Saudi visa?  I am Indian passport holder. Do I need to exit Riyadh, go back to India, and then get an extension? and then re-enter?

i need any agent no ?

Any advice much appreciated.

You can ask the company that issued the visa for you to extend the visa if you are not planning to go out of the country in 30 days. Doing so will disable the multiple nature of the visa and then you can stay on only for a further 30 days more and then you will need to exit and come back on a new visa. However if you exit every month ( to bahrain via road) you can keep the multiple nature and stay for a duration not exceeding 3 months.

if  need Bahrain visa via road side ?

Depends on your nationality to get visa to Bahrain from Causeway bridge. However you do not need to enter Bahrain, you can just exit KSA and make a u turn back to KSA if the aim is only to keep the multiple nature of the visa.