Template Variables

Prism expands ${variable} placeholders in metadata files during the build.

Supported files

• fabric.mod.json
• META-INF/mods.toml
• META-INF/neoforge.mods.toml
• pack.mcmeta
• *.mixins.json

JSON files (fabric.mod.json, pack.mcmeta, *.mixins.json) have newlines escaped as \\n. TOML files (mods.toml, neoforge.mods.toml) are expanded as-is.

Available variables

Common (all subprojects)

Variable	Source	Example
version	metadata.version	1.0.0
group	metadata.group	com.example
minecraft_version	version block	1.21.1
mod_name	metadata.name	My Mod
mod_author	metadata.authors (joined)	Alice, Bob
mod_id	metadata.modId	mymod
license	metadata.license	MIT
description	metadata.description	A mod.
java_version	detected or override	21
credits	metadata.credits (joined)	Charlie

Fabric subprojects only

Variable	Source	Example
fabric_loader_version	fabric.loaderVersion	0.16.2
fabric_version	fabric.apiVersion	0.102.1

NeoForge subprojects only

Variable	Source	Example
neoforge_version	neoforge.loaderVersion	21.1.26
neoforge_loader_version_range	always [4,)	[4,)

Forge subprojects only (MDG Legacy, 1.17–1.20.1)

Variable	Source	Example
forge_version	forge.loaderVersion	47.2.0
forge_loader_version_range	always [4,)	[4,)

LexForge subprojects only (ForgeGradle 7, 1.21.1+)

Variable	Source	Example
lexforge_version	lexForge.loaderVersion	52.0.0
lexforge_loader_version_range	lexForge.loaderVersionRange	[52,)

Loader-specific variables are only available in subprojects for that loader — fabric_loader_version is only set in Fabric subprojects, and so on. Using a Fabric variable in a NeoForge TOML file will leave the placeholder unexpanded.

Custom variables

Add your own variables with metadata.expand(key, value). The value may be a string or a Provider<String> (resolved at build time):

prism {
    metadata {
        expand("commit", gitCommit())
        expand("homepage", "https://example.com")
    }
}

These become ${commit} and ${homepage} in all supported files.

Example

fabric.mod.json

{
  "schemaVersion": 1,
  "id": "${mod_id}",
  "version": "${version}",
  "name": "${mod_name}",
  "description": "${description}",
  "authors": ["${mod_author}"],
  "license": "${license}",
  "depends": {
    "fabricloader": ">=${fabric_loader_version}",
    "minecraft": "${minecraft_version}"
  }
}

META-INF/neoforge.mods.toml

modLoader = "javafml"
loaderVersion = "${neoforge_loader_version_range}"

[[mods]]
modId = "${mod_id}"
version = "${version}"
displayName = "${mod_name}"
description = "${description}"
authors = "${mod_author}"
license = "${license}"

META-INF/mods.toml (LexForge, 1.21.1+)

modLoader = "javafml"
loaderVersion = "${lexforge_loader_version_range}"

[[mods]]
modId = "${mod_id}"
version = "${version}"
displayName = "${mod_name}"