Very good and welcome development. Since the inception of Pakistan, KSA has always been a close partner bound by a religious, cultural, geographic and ancient historical bond (the first recorded civilizations/cultures in what is today Pakistan, (IVC), were close partners of contemporary civilizations in Arabia (Sumer, Dilmun, Magan etc.) and in fact it where our forefathers who first described the IVC to the outside world during that long bygone era.
A lot of people to people relations in the modern era, almost exclusively Pakistani workforce in KSA.
I would like to see this new development result in something truly tangible for both parties in terms of the military sector but not only. Expand this cooperation economically, in terms of agriculture, mining, AI, technology, STEM, culture, transportation and what not.
Hopefully this will benefit the ordinary man and woman in both KSA and Pakistan.
I just have some questions, and I wonder if we have the details.
A. Would Pakistan be involved in Saudi wars in Yemen, Syria, and Sudan, and possibly Iran?
Most Pakistanis would be fine with protecting Saudi Arabia itself but not with fighting other friendly nations.
B. Would Saudi Arabia come to help against India, even if not militarily, but at least economically, diplomatically?
C. Will our troops, including the Air Force, air defense, and armed forces, be stationed in Saudi Arabia alongside the Americans, who already perform air defense duties (as far as I know)?
So even if Israel attacks Saudi Arabia, we might not have sufficient resources stationed there to help them ward off such an attack.
There are no "Saudi Arabian wars" in fellow Arab countries whether in neighbouring Yemen, Syria or Sudan. The Syrian civil war ended last December. KSA is not actively involved in Sudan either and if involved, it supports the official government and military, as was done in Yemen.
Since 2020, KSA is no longer involved in Yemen and have signed peace deals with Houthis. There is an established understanding and the status quo is intact after the Yemeni civil war (Houthis remain in control of the Zaydi mountanious heartlands and KSA/official Yemeni army/government, controlling the remaining 80% of Yemen)
Last time there was an KSA/Iran war was 1400 years ago during the Arab Islamic conquest. Afterwards the degree of "animosity" in terms of conflict can be boiled down to numerous Arab dynasties ruling Iran, long after direct Arab Caliphate rule.
For example the longest ruling Iranian dynasty in history was originally of Arab origin.
en.wikipedia.org
Many others before and after.
en.wikipedia.org
The Safavids claimed Arab ancestry and intermarried with Arab Sadah families (plural of Sayyid).
It was during the Safavids that Iran became majority Shia Muslim courtesy of imported Arab Shia clerics from modern-day Eastern KSA and Bahrain plus Southern Iraq next door and Lebanon.
Hence my Mullah's like Khamenei and Khomeini are fruits of those migrations. At least both claim so.
en.wikipedia.org
Nowadays there is no hostility and relations have cooled down. As long as Iran is not actively meddling in internal Arab affairs in a negative way and supporting non-state militant/terrorist actors, there is no reason for any hostility. We are permanent neighbours and have much in common as well as deep ties on most fronts, in particular with Eastern Arabia/Iraq and Southern Iran.
Not to mention that millions of Arabs live in Iran and have done so long before the appearance of Islam.
Most of pre-Islamic Iranian civilization/culture was also extremely influenced by our ancient Semitic cultures (Babylonian empire, Sumer etc.) which in many ways "civilized" the Persians early on and whose culture, language (Akkadian - closely related to Arabic), and symbols, architecture, civilization, art, they all copied.
Rest of your questions we do not know the answers of, as nobody here knows the inner details of this deal.
But I can already tell you this, the main goal of KSA, is stability (regional) and economic progress. Not starting any new wars or conflicts unless attacked.
KSA is going to host the World Cup, Asian Games, AFC football tournament, numerous sporting and cultural events and has emerged (only will be bigger by each month) as a tourist and cultural hub on a global scale. KSA is also undergoing huge cultural, economic and social changes in the past 10 years.
None of the above fits into some scenario where KSA is suddenly going on the offensive without reason.
If anything this is a message to the US's rapid attack dog (Israel) that you cannot attack KSA and get away with it, even if you have the US/West/NATO as your obedient slaves.