In career mode, you can hire AI pilots, who'll become part of your Lance.
They will pilot Mechs you own and fight by your side on missions.

Pilots have:

• Weapon Skills
  
• Piloting Skills
  
• An AI Type (this is hidden from you)
  
• Salary
  
• Voice & Image (but they're just cosmetic)

To have the best AI companion pilots, you want them to be 60/60 on skills and for them to have Elite AI.

This guide won't discuss which mechs & weapons you should give your AI pilots.
There are other guides / forum conversations on that topic.
Though, if you really want my two cents, I'd recommend giving them Gauss, Heavy/Medium Rifles and LB 10-X AC-SLD.

If you observe enemies, you might see words like "Green", "Regular", "Veteran" or "Elite" displayed next to the unit.


This lets you know how competent the AI unit is and how accurate and smart they are.



For example, Green units are more likely to miss you while Elites will generally hit you.
Aggressiveness and spatial awareness are also linked to AI level. (Some AI has been observed to move to stand on a rock to be able to snipe at enemies more easily.)

You may need to click it to enlarge it.
This image shows how Recruits and Elites have wildly different accuracy values.

You're not told directly, but generally their military ranks and bio descriptions inform you of what you're dealing with.

Compare these two pilots:


The descriptive sentences associated with Elite AI and Veteran AI are displayed in the images below.
You can check which AI your pilot should have by referencing these lists and seeing if your pilot has two different sentences in their bio from the same category (Elite/Veteran).

Some sentences are shared by both male and female pilots (the pronouns however are switched), but there are also tables of descriptive sentences which are specific to males and females.

(FYI: The sentences in the 'SkillSentence_Elite' and 'SecondarySentence_Elite' tables are the same for male Elite pilots.
Therefore, sometimes you may find a male pilot who has two of the same sentence in their bio.)

You may need to click on the images to enlarge them, if the text is too small.
Opening the image's URL will show you a better quality image.

The images as text: https://pastebin.com/b8n4zFJA
Note: The text might not be 1:1 due to it being OCR-generated.
(Credit for the link & text: Mclang.)

Majors have generally the best AI.
Captains have generally second best AI.
Lieutenants usually aren't very good.

Even if a lieutenant had 60/60 stats, it might perform considerably worse than a 20/20 Major, as even if they deal more damage they will be less likely to begin targeting enemies early and actually landing shots.

There is very strong correlation between Majors and said pilot having the descriptive sentences, which indicate they should have Elite AI.
(This may even always happen, unless there's a bug / a mod disrupts something.)

You should still check the Major's bio to make sure they have the correct descriptive sentences (which are displayed in the section above this one).

Note that the first part of the bio usually starts with where they come from and why they became a Mech pilot. That part of the biography appears to not influence which type of AI they'll have.

A pilot's salary might not determine how good their AI is or improve it, but if you're a superstitious type you could aim to only hire X/60 Majors with a salary over at least 20,500.

Rank up your reputation.
Majors will begin spawning around reputation Rank 13 (Elite).
So until your reputation is high, feel free to rely on captain rank pilots.



In my experience, checking star systems around Terra will provide you with easiest X/60 Majors.



You can refresh the pilots available at systems by traveling away from Terra until you no longer see icons like those above Keid and Sirius in the image above.
Then just go back to check the new pilots. (This may cost a lot of money after a while.)

You're unlikely to find a straight up 60/60 pilot at stores, so you'll need to train your 48/60 pilot or 55/60 pilot into a 60/60 pilot.

Keep playing with your chosen pilots until they reach max experience with their skills.
Remember to give them a mech with ballistic weapons if you want their ballistic skill to improve, etc.

Low damage in post-mission screens might not indicate the pilot has bad AI.
Some maps favor specific types of weaponry.
Generally aggressive AI with solid long range weapons (Gauss, Rifles, solid slugs, PCC, etc) will end up dealing a lot of damage on open maps with lots of direct line of sight, as close-combat Mechs won't get many chances to attack due to how your most suited Mechs will snipe the enemies before they manage to get close.
If one of your Mechs is considerably slower than the others, the pilot might also end up dealing low amounts of damage.

In addition to my own research and observations regarding the topic of this guide, information from these people assisted in the making of this guide:

Strayed.
He's an experienced member of the MW5 community and has done some modding and examined AI related files for the game.
He provided valuable screenshots of the descriptive sentences & AI's accuracy values.
(He shared some of his knowledge and observations concerning this topic as well.)

Templar Vandalos.
Some information was derived from/supported by Templar Vandalos's video.
https://www.youtube.com/watch?v=b1-VWWRbsOE
You can find out more about the topic from his video, but this guide should be enough for you to get a pretty good idea.
(Note: Some information about whether specific things influence AI behavior is unconfirmed.)

Mclang.
They used OCR software to compile the text from the AI Veteran / Elite descriptions into a text file and linked said pastebin file. ( https://pastebin.com/b8n4zFJA )
(If the contents of the bin change, I am not responsible for it and feel free to comment if the link doesn't work anymore.)

Graphics Credit: Horatio's Mouth.
His mouth was used transformatively for the guide's icon, which also features an NPC pilot's avatar from MW5.

JDCollie.
I've not tested or verified this mod, but JDCollie mentioned having made a mod which modifies pilot descriptions to indicate which AI type the pilot has: https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3144882464

Feel free to let me know.
I could update the guide if it's something very crucial or even add a section written by you into the guide & add you to the credits (if you wish).