Vidya - Agave

If you don't have Vidya - Agave yet but want to try her out, she is available as a Trial Operative in Story Mission SP3-8

Agave's damage is decent, she has decent mobility, her skill has auto-aim and AoE as well as long- range, so even ignoring Agave's two biggest... *ahem* assets, she is one of the most popular characters for casual play, just because she is so easy and simple to play.
For endgame content Agave doesn't have the dps to be a competitive Main DPS, but Agave is the best Parts Breaker in the game by-far, and whilst Parts Breaking isn't overly useful at endgame when it is needed Agave is the default and best choice, with her support skill being a nice 20% ATK buff as well, whih also makes her a decent early-game support due to how little investment is needed to get her buff.

The Basics

Role: Agave can fill all team roles
(Some better than others)
Electric Damage
Deals almost entirely skill damage
Mobility is good

Advantages

Strongest Parts Breaker in the game by-far
Simple and easy damage rotation
Her Standard Skill has Auto-Aim
Her Standard Skill has a very long range
Support Skill is pretty good
(Especially for such low investment)

Disadvantages

Parts Breaking is not overly useful at endgame
Damage is mediore
Gun does not have auto-aim
Once her S-Energy runs out you do actually have to aim and land hits with her gun
Her weapon buffs cover her outfits

How to use Vidya - Agave

There are 2 ways to use Vidya - Agave:

As a dedicated Parts Breaker
Keep Agave off-field until Parts Breaking is needed. Swap Agave in, Parts Break with her, then immediately swap her out when done.
(Use her Support Skill off-cooldown if doing this - it gives a 20% ATK buff)
(Note Agave's Support Buff affects the entire team, including herself if she is switched back in whilst it is active, so if you time it well she can buff herself too.)

As a Main-DPS:
1. Use her standard skill until you run out of S-Energy
2. Use her Ultimate
3. Shoot until all her S-Energy has been recovered.
Repeat

Standard Skill
Fires a homing projectile at the target, which deals PBAoE Electric Damage on hit.
Using the skill continuously increases its phase - projectiles fired at higher phases do more damage with higher AoE, but use more S-Energy.
The damage increase from phase increases is massive - Phase 4 deals around 350% the damage of Phase 1.
If Agave shoots her gun or doesn't use the skill for 2 seconds, Phase resets back to 0.

For each hit with her Standard Skill, Agave gains Personal Flair (which is used for her Ultimate).
Each hit gives Agave 1 Personal Flair per Phase level.

If her standard skill hits a destructible part, it also damages another destructible part. (Or deals more damage if only 1 part is available to hit)
Hitting a destructible part also reduces the next skills S-Energy cost by 25% per part hit.
If a destructible part is destroyed, reduce S-Energy consumption by 50% for 3s.

If the skill defeats a target, her next skill usage with 5 seconds doesn't use S-Energy.

Agave can move whilst using this skill, but it isn't quite as fast as moving normally, meaning she has lower mobility than your average operative, but it's still not bad.

Standard Attack
Agave shoots her gun.
Agave recovers S-Energy per hit with her gun.
Since Agave does not naturally recover S-Energy whilst she's on the field, landing hits with her gun is her only in-combat method of recovering S-Energy.

Note that the Skill Damage buff from her 4* and 5* signature weapons are removed whenever Agave shoots.

Ultimate Skill
Agave deals AoE damage - the more Personal Flair stacks she has, the more damage dealt.
Note that the damage of Agave's ult isn't quite linearly proportional to the number of Personal Flair stacks she has.
Agave's standard skill rotation tends to end up giving her 30 Personal Flair.
Using three ults at 30 Personal Flair deals 20.5% more total damage than one ult at 90 Personal Flair.

Agave loses her Skill DMG buffs when she shoots, so make sure to always use her ult after using her Standard Skill - never use her ult directly after firing her gun.
Her 4* weapon needs 4 standard skill casts to max its buff. Her 5* weapon needs 3 casts.

If Agave has 20 stacks of Personal Flair or more (which she should always have if you're doing her rotation properly), then after using her ult her next Standard Skill usage within 10 seconds skips straight to Phase 4.
As such, after using her standard skill until she runs out of S-Energy, she should ult immediately.
This allows her to keep her Skill DMG buffs from her gun and have them apply to her ult, whilst also skipping to Phase.4 after regaining her S-Energy, which allows her to not waste S-Energy using weaker Phase 1/2/3 casts.

Whilst you can use her standard skill, shoot, repeat until her Personal Flair stacks are at max, and then Ultimate, this results in less damage than just ulting immediately after her E-Eenrgy runs out.
Two ults at around 50 Personal Flair deal more total damage than one ult at 100 Personal Flair.
Not using her ult means that after shooting she has to start her standard skill from Phase.1 again, wasting damage by not using the buff that allows her to skip to Phase.4.
As such, getting to 100 Personal Flair is just a DPS loss, so avoid doing it and instead just Ult when she runs out of S-Energy as per the 3-step rotation listed in the "How to use Vidya - Agave" section above.

Support Skill

Agave's Support Skill causes her to deal Electrical DMG + Paraylze (for 2s) in an AoE in front of her.
Note that the stun and damage from her Support Skill are not really very useful - you're using it for the ATK buff [below] only, really.
This uses 20% of Agave's S-Energy. If this causes Agave to use more than 10 S-Energy, Agave gives the entire squad a 2% ATK bonus for 15s per S-Energy over 10 she used.
Given that this skill has a 15s duration, Agave will always be at full S-Energy when it is used.
With Agave's passive +30 max S-Energy and her 4* or 5* weapons +20 max S-Energy, Agave has a max S-Energy of 100, meaning 20% of her S-Energy is 20 S-Energy.
Using 20 S-Energy means Agave uses 10 more than 10, so her Support Skill gives the entire team a 10 * 2% = 20% ATK buff.

Given that this is a 15s buff on a 15s CD, provided you spam it off-cooldown it's basically permanent.

ATK tends to get quite a few buffs (Logistics, Logistics substats, Manifestation levels, other support operatives....) and is quite a saturated category, but despite this, 20% ATK is a good bonus considering it's basically permanent.
Agave also gives a pure-ATK boost, which almost every main DPS operative in the game benefits from.
Many other operatives like Celestial Swan, Nightglow, Starshine, Phantasia, Kaguya, Exuvia, etc. all have some restriction on who can use their buffs.

Provided Agave has her 4* or 5* weapon, she can provide this full 20% ATK buff, which is a very low barrier to entry.
Agave doesn't get any bonus to her Support Skill from her Manifestations, and her Neuronics and Deiwos also don't functionally change it, so Agave having her 4* or 5* weapon is all that she actually needs to be a decent support.

Is Agave a great support?
Not really - compared to other support operatives like Celestial Swan, Nightglow, Riptide, Kaguya, Starshine, etc., Agave does fall short, but Agave provides a strong benefit with 100% uptime and zero investment outside of just having Agave and having one of her signature weapons.

Will Agave make it onto an endgame team as a support? Not unless Parts Breaking is needed, no.
Is Agave a decent support though? Yes, and given how easy to use and easy to get she is, that does give her a useful role as an early-game support operative if you have her.

Weapon

Snapshot Ace
Her 5*, and her best weapon.
Pure Verdure
Her signature 4*. Use this if you aren't using Snapshot Ace.

For Weapon Parts just go max ATK.

Logistics

Use Chaya squad - it was designed specifically for her and is her best choice.

For stats you want +10.0% ATK and 10.6% Alignment Index.
For the Special talent, you want 8.5% Electrical Damage

Skills can't crit, so since most of Agave's damage is in her skills, crit stats are not overly useful to her.
Similarly, Alignment Index gives skill damage, making it very useful, and her second best stat after ATK.
Due to Agave's constant skill spamming, Skill Haste is a good cope stat. Not as good as Alignment, but not the worst.
All other stats are useless.

Manifestation

M1 decreases the S-Energy of her Standard Skill by 2 when at phase 2, 3, and 4. She also recovers 2 S-Energy per shot instead of 1.
The reduced S-Energy cost allows Agave to use her Standard Skill 1 additional time per rotation.
This is true regardless of whether Agave starts at Phase 0 or Phase 4.
Recovering 2 bullets per standard skill hit means that Vidya only has to shoot half as much, allowing her to use her standard skill much more frequently.
Since her standard skill is where the vast majority of Agave's damage comes from, this is a large damage buff.
Combining the longer rotation and the lower downtime, M1 is a huge damage buff for Agave.
M2 increases the Final damage of Agave's standard skill by 8/12/15/20% depending on its phase.
For endgame content, Agave is pretty much only going to be using her standard skill at Phase 4, so it averages a maybe 19% damage buff for endgame content.
M3 allows Vidya to recover S-Energy by 3 per shot, and decreases the targets DEF by 15% for 5s.
This increased S-Energy per shot again allows Vidya less downtime for her standard skill [to 2/3rds], and thus shortens her rotation, increasing damage.
The DEF bonus is a nice damage buff.
M4 increases the level of Agave's standard skill by 1, as well as increasing the damage of her standard skill by 10%.
Since almost all of Agave's damage comes from her standard skill, this is a very nice boost, but it is just more damage.
M5 increases the Final DMG of Agave's active skills byu 0.1% per 1 Max S-Energy.
Given Agave generally has 100 max S-Energy, this is a 10% Final DMG boost to her skills.
Being a Final DMG boost makes this very strong, but it is only 10%.
Like M4, it's just more damage.

M1 and M3 are nice QoL buffs to Agave, whereas M2, M4, and M5 are just more damage.
As such, if you want efficiency (good damage without high investment), then M3 is a good stopping point.

Good Teammates for Agave

As a main DPS Agave really wants Skill DMG buffs or to debuff enemy resistances.
Whilst Agave does shoot her gun sometimes, it's both weak and with a low total number of shots.

Vidya - Celestial Swan (and other resistance shredders)
Celestial Swan and other resistance shredders (Acacia - Kaguya, etc.) that reduce the enemies resistance help enemies take more damage.
If using Celestial Swan, make sure the other support isn't off element to Agave (i.e. deals Electrical Damage)
Nightglow
Agave can't make much use of Nightglows ballistic or crit buffs, but Nightglow's ATK buff is nice.
Nightglow is also on-element to Agave. (Nightglow deals Electrical damage)
Enya - Exuvia
Skill buffs are very nice for Agave, and she does regularly shoot her gun, allowing her to make good use of Exuvia's buffs.
Eatchel - The Cub
A Blitzing Fangs Eatchel provides healing as well as a decent ATK buff, without dealing any damage herself.
Not the strongest support, but still good.
Marian - Riptide
Riptide gives some very nice Skill DMG boosts
The low duration of Agave's ult buff as well as the very short duration of Agave's weapon buffs can make Riptide difficult to fit in to Agave's rotation.
Note that Riptide is off-element to Agave (Riptide deals Chaos damage)
Mauxir - Shadow Ka
Agave's auto-aim means Mauxitr's target utiliy isn't useful for her skills, but it can be useful for her gun, and the extra damage is nice regardless.
Note that Shadow Ka is off-element to Agave (Shadow Ka deals Chaos damage)