Factorio.toml

Factorio.toml sits next to Cargo.toml in the project root.

Top level

Key	Default	Description
source	"src"	Root of Rust sources to transpile
output_dir	"dist"	Mod output directory (wiped each build)

[mod]

Written into info.json (and related packaging):

Key	Description
title	Display title
description	Optional description
factorio_version	Factorio version string (default "2.0"); also used for a base dependency
thumbnail	Optional path to an image copied to thumbnail.png in the mod output

Mod name / zip id still come from Cargo [package].name and version.

Thumbnail

Factorio’s mod portal expects thumbnail.png in the mod root (commonly 144×144). By default, if thumbnail.png exists in the project root it is copied into dist/ on build. Override the source path with:

[mod]
thumbnail = "assets/thumbnail.png"

If thumbnail is set and the file is missing, the build fails.

[emit]

Key	Description
lua_module_prefix	Prefix applied to the last segment of Lua module paths (e.g. "msr" -> msr_control.lua)

[profiles.<name>]

Key	Description
debug_level	Lua debug comment level
prune_dead_code	Whether to prune unreachable IR

See Profiles.

Example

source = "src"
output_dir = "dist"

[mod]
title = "My Mod"
description = "Does things"
factorio_version = "2.0"
thumbnail = "thumbnail.png"

[emit]
lua_module_prefix = "mm"

[profiles.debug]
debug_level = 2
prune_dead_code = false

[profiles.release]
debug_level = 0
prune_dead_code = true