Question: Is the Arcana Skill capable of influencing or affecting actual spells being cast or other spell-centred details? For example, are you able to influence the effect or characteristics of a spell by rolling a high enough Arcana check? Or does that fall primarily within relation to magic items and not cast spells?

Answer: 
According to the D&D 5e *Basic Rules* (as published on [D&D Beyond](https://www.dndbeyond.com/sources/basic-rules/using-ability-scores)), Arcana is defined as:

> 
> Arcana
> 
> 
> Your Intelligence (Arcana) check measures your ability to
> recall lore about spells, magic items, eldritch symbols, magical
> traditions, the planes of existence, and the inhabitants of those
> planes.
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> 
> 

Any usage other than that would be purely up to your DM, but as described above, you could use your proficiency in Arcana to identify a spell or know lore about it, but not to cast or modify it in any way.
The closest to this the Arcana skill has is to identify a spell being cast
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With the arcana ability, one can deduce what spell is being cast or has been cast. From *Xanathar's Guide to Everything*, pg. 85, under ["Identifying a Spell"](https://www.dndbeyond.com/sources/xgte/dungeon-masters-tools#IdentifyingaSpell):

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> Sometimes a character wants to identify a spell that someone else is casting or that was already cast. To do so, a character can use their reaction to identify a spell as it's being cast, or they can use an action on their turn to identify a spell by its effect after it is cast.
> 
> 
> If the character perceived the casting, the spell's effect, or both, the character can make an Intelligence (Arcana) check with the reaction or action. The DC equals 15 + the spell's level. If the spell is cast as a class spell and the character is a member of that class, the check is made with advantage.
> 
> 
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Informative wizard companion
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In practice, this can be useful for a companion of a wizard to identify a spell as it's being cast to shout in order to inform the wizard to use their reaction to cast [*counterspell*](https://www.dndbeyond.com/spells/counterspell). In this way, the Arcana skill can be used to facilitate when to know when to ~~modify~~ *counter* a spell being cast.