Alright, I need the community to settle this because one of us is wrong here. (This is NOT a specific game in play rules question, I am trying to build a rules database, so if there is somewhere else I can post this, please let me know, this is hypothetical situation that has happened to me before)

For context, I’ve been working with an AI where I’ve uploaded:

• the full Comprehensive Rules (https://magic.wizards.com/en/rules)
• Commander rules (https://magic.wizards.com/en/formats/commander)
• AND every single Commander-legal card (with rulings from skryfall)

I’ve had it train in a very deep level toward a Level 3 judge-style understanding of the game, meaning it’s breaking interactions down by rules layers, replacement effects, control effects, etc.

I am trying to build something that can be updated easily and quickly with new rules and with each new set that comes out with new cards that are easily entered into the system.

So this isn’t a casual “I think this works” debate… this is a rules-level disagreement.

Scenario:

Player A controls Opposition Agent
Player B casts Praetor’s Grasp targeting Player C

Praetor’s Grasp → Player B searches Player C’s library

Opposition Agent says:
“You control your opponents while they’re searching their libraries…”

The Argument:

Side 1 (me pushing back):
“Opposition Agent says THEIR library. Player B is searching Player C’s library, NOT their own. So Opposition Agent should NOT apply.”

Side 2 (AI / rules-based argument):
“The game only cares about WHO is performing the search. Player B is searching a library, so Opposition Agent applies regardless of ownership.”

Here’s the deeper rules breakdown we’re working from:

There is not a standalone Comprehensive Rules sentence that literally says, “for Opposition Agent, ‘their library’ includes another player’s library.” The clean rules-based answer is:

• The CR defines searching as a player searching a zone, not necessarily their own zone
• The CR explicitly calls out Opposition Agent as one of the cards that lets you control another player for a limited duration
• The card’s official ruling text then closes the gap and confirms how Opposition Agent works in these search situations

So, on this interaction, the conclusion from that framework is that Opposition Agent still applies when Player B searches Player C’s library.

Rules chain (condensed but accurate):

• Rule 701.23a → Searching is a player searching a zone (not limited to their own library)
• 701.23b / 701.23c → Examples explicitly show players searching other players’ libraries
• Rule 722.2 → Opposition Agent is one of the cards that lets you control another player
• Rule 722.5 → You make all decisions for that player while controlling them, including search choices

The key point is:
The rules care about who is performing the search, not who owns the library

Card rulings (this is the nail in the coffin):

• If you control an opponent while they search, you decide what they find
• Cards found are exiled instead of going where the original effect says

That only makes sense if Opposition Agent applies based on the player performing the search, not ownership of the library.

So the final outcome would be:

• Player B is instructed to search
• Opposition Agent applies
• Player A controls Player B during the search
• Player A chooses the card
• The card is exiled under Opposition Agent
• Player A gets to play it

Player B does NOT actually benefit from Praetor’s Grasp

So who’s wrong?

A) Opposition Agent only works on a player’s own library
or
B) It applies anytime an opponent is the one performing the search

If you’ve got judge experience or hard rule citations, I want to hear it. Let’s settle this properly.