Do a Soulknife’s soulknife abilities function in an Antimagic Field?

Question

The Soulknife’s soulknife comes from their Psychic Blades subclass feature, which states:

“Also at 3rd level, you can manifest your psionic power as shimmering blades of psychic energy. Whenever you take the Attack action, you can manifest a psychic blade from your free hand and make the attack with that blade. This magic blade is a simple melee weapon with the finesse and thrown properties.”

So would a soulknife disappear in an antimagic field, or would it merely be a suppressed magic weapon?

If it's the later, would you be able to manifest it in an antimagic field given that it uses psionic energy to manifest even though it’s a magic weapon?

Would the other Soulknife class features that use the soulknife but aren’t described as magical still function, even if the soulknife is now a suppressed magic weapon?

Also for the parameters of the question assume that this unofficial tweet is correct: https://twitter.com/JeremyECrawford/status/1252282928576335875:

The antimagic field spell in D&D affects spells, magic items, and other effects that are expressly magical. The spell doesn't care about the source of those things (arcane, divine, psionic, or something else).

So some psionic effects would be affected and some wouldn't.

Answer 1

Psychic Blades is magic, so it is suppressed completely.

The Sage Advice Compendium tells us how to determine if something is magical:

Determining whether a game feature is magical is straightforward. Ask yourself these questions about the feature:

• Is it a magic item?
• Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description?
• Is it a spell attack?
• Is it fueled by the use of spell slots?
• Does its description say it’s magical?

If your answer to any of those questions is yes, the feature is magical.

Psychic Blades states:

This magic blade...

So it is suppressed in an antimagic field. It is not like a Sword +1, which is a usual sword with a magical enchantment that is suppressed, it is a sword made entirely of psychic energy, created and sustained by an expressly magical power. It is gone in the antimagic field.

You will have to ask your DM about the other features.

You are basing this question on assumption made by another DM, an assumption that is unhelpfully non-specific, from this tweet:

some psionic effects would be affected and some wouldn't.

Jeremy Crawford gives absolutely no guidance for determining which psionic effects count and which ones don't, only ambiguously stating that some do and some don't, so you will have to ask your DM about the other psionic features in the Soulknife feature list.

To give some guidance, if one of the other Soulknife features modifies or uses the Psychic Blades feature, it probably doesn't work, since the Psychic Blades are expressly magical, and so cannot exist in an antimagic field.

Answer 2

"Rend mind" would not function in this case since it needs psychic blades to work.
They do not function in anti-magic.

Answer 3

The Soul Knife is described as magical but the feature that creates it is not, so its magic would be merely suppressed in an antimagic field, similar to how a "Pact of the Blade" weapon is merely suppressed in a antimagic field. It being made of psychic energy is unimportant as psychic energy is not explicitly magical. As for the other blade related features, only "Homing Strike" and "Rend Mind" would function as "Psychic Veil" is explicitly magical and no form of teleportation is allowed in an antimagic field thus disallowing "Psychic Teleportation".