Howdy folks!

For me, the companion should provide [Enemy Radar] and collect the resources while providing utility during combat. Also it's important to be hard to kill so you won't lose your little helper during the mission.

Let's talk about the mods:

• Primed Animal Instinct + Vacuum -> Those 2 give your guy the ability to see the enemies on the map and grab the loot when in close proximity.

• Guardian + Medi-Ray -> I said about providing utility during combat, those 2 will heal your warframe in combat.

• Primed Regen -> In longer runs, your sentinel might die. Primed regen gives your companion 3 more lives.

• Repair Kit -> I know it's slow but it's the only way to heal the sentient.

• Enhanced Vitality + Metal Fiber -> Your guy needs some stats, it must be able to catch a few bullets without dying.

• Accelerated Deflection -> Since shield gating it's a thing, it's better to have a small shield which regenerates faster instead of a big slow one.

• Ammo Case -> This is [Carrier]'s special mod, which takes care of ammo problems.

***A few words about Shield Gating

Shield Gating is an effect that occurs when shields are fully depleted, which prevents any excess damage leaking into the health pool. Warframes, Companions, and Necramechs gain 1.3 seconds of invulnerability upon hitting the shield gate, only resetting when shields are allowed to fully replenish. If the shield is still in the process of recharging after the gate has activated, the shield gate will only last for 0.33 seconds.

Other viable mods choices:

• Animal Instinct - It can replace Primed Animal Instinct if you don't have it.
• Regen - It can replace Primed Regen if you don't have it.
• Synth Fiber - Extra armor is nice.

*PROS and CONS*

• Sentinel weapon modsets bonuses
• Solves ammo issues
• Not as squishy as other companions (e.g. Djinn)

• Smeeta Kavats provide more utility
• Ammo issues are not as common today since weapon exilus mods can take care of it (Ammo mutation mods and Vigilante Supplies)

Conclusion

[Carrier] used to be one of the most popular companion choices. It's popularity fell to the ground after weapon exilus mods were added. Since ammo is not an issue anymore, Smeeta Kavats are a better option.

Check out my other companion builds:

• Djinn - Self revive companion
• Panzer Vulpaphyla - The Immortal Fox
• Adarza Kavat - Critical Eidolon Hunter
• Smeeta Kavat - The most useful companion