Psi
by Vazkii
Psi brings spell programming to Minecraft, letting players build spells out of pieces that are wired together on a programming surface.
What it does
Psi is a magic and technology mod whose spells are assembled rather than cast from a fixed list. A player combines spell pieces into a program, and the program then runs when the spell is triggered. The design takes its inspiration from Mahouka Kokou Rettousei, and the mod leaves much of the composition to the player, so the same parts can be arranged in many different ways.
The mod is installed on Fabric, Forge and NeoForge, and it needs both the server and every player to run it, since the client and server share the environment. Psi requires Fabric API and Patchouli, and the Patchouli guide documents the mod in game. Files target 1.12.2, 1.16.5, 1.18.2, 1.19.2, 1.19.3, 1.19.4, 1.20.1 and 1.21.1. The mod is released under a custom license and is not open source, though its source code and issue tracker are public.
Key features
Spell programming
Spells are built by linking pieces together into a program, so the player decides what each spell does and in what order.
Creative problem solving
Because the pieces combine freely, a player has to plan a working program, which rewards experimentation.
Technology and magic crafting
Tools and components tied to the spell system are crafted from the same resources the player gathers while progressing.
Reward for the creation process
Finished programs and components become part of the player's progress, so building a working spell is itself the goal.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 2
Required by 10 mods
How it compares
PsiEX is an add-on for Forge and NeoForge that builds on the same system, with files for 1.20.1 – 1.21.1 under the MIT License. Fantazia is a Forge and NeoForge mod for 1.19.3 – 1.21.1 under All rights reserved and is not open source. Magical Programming is a Fabric-only mod for 1.20.4 under the MIT License, limited to one loader and one game version.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Psi | Fabric, Forge and NeoForge | 1.12.2 – 1.21.1 | Client and server | 2026-09-01 |
| PsiEX | Forge and NeoForge | 1.20.1 – 1.21.1 | Client and server | 2026-07-24 |
| Fantazia | Forge and NeoForge | 1.19.3 – 1.21.1 | Client and server | 2025-12-15 |
| Magical Programming | Fabric | 1.20.4 | Client and server | 2024-04-20 |
Questions
Does Psi need Fabric API on every loader?
Does Psi have to be installed on the server?
Which versions of Psi have files for Forge?
In the catalog
Psi is one of 7,216 Magic mods on ModsFinder, and one of 3,630 Magic mods for Fabric. 32,366 mods support Minecraft 1.21.1.
More from Vazkii
Similar mods
What the author says
Warning: Psi Requires Patchouli for 1.16.5 and more recent versions. Older versions require AutoRegLib Psi is a magical tech spell programming mod inspired by Mahouka Kokou no Rettousei. Don't worry if that doesn't make any sense.
Official listing
- Modrinth page
- modrinth.com/mod/psi
- Owner
- Vazkii
- Published
- 2022-05-30
- Updated on Modrinth
- 2026-09-01
- Facts verified
- 2026-10-15