Enabled mods

Installing a mod puts it on the machine, under assets/workshop/<author>/<mod>/. Enabling it puts it in the session. The two are separate, and the session is the one that decides: a player who installs a mod, returns to the menu and hosts again gets it without relaunching, and a mod you disable stays on disk for the next session that wants it.

A mod is the one unit here — a gamemode, a map, a library another mod builds on are all mods, each named by its full two-segment id, author:mod. See Mod identity.

Enable a set

In config/server.toml:

[session]
mods = ["acme:chat", "acme:shop"]

List the mods you actually want. Anything a listed mod declares it needs is pulled in for you, so the list stays short and stays yours.

Three states, three intentions

Written	Runs
no `mods` key	everything installed — nobody has curated this install
`mods = []`	the baseline alone — curated down on purpose
`mods = [...]`	the baseline, these, and what these need

The baseline leads

Two mods ship with the game and are enabled in every session: ironlark:freeroam, the fallback gamemode, and ironlark:badgrass, the default map. They load first, you never list them, and an empty list still runs them — that is what keeps a bare session playable.

Write everything else in full. Every entry is matched against the whole author:mod id, and an entry that is not an id at all refuses the session naming the text — chat alone is not an id, and a session listing it will not start.

Load order is derived, not written

Each mod declares what it needs in its manifest’s [needs] table, with a version range per requirement — see Dependencies. The session resolves the closure over those declarations, and orders it so that dependencies load before their dependents, always.

Your list’s order is only the tiebreak between mods neither of which needs the other. It can never override a declared need, so “reorder the list” is not how you fix a startup race — the mod that reacts to another’s startup declares the need, and the resolver does the rest. A mod the closure pulled in that nobody listed rides at the position of the earliest mod that needed it.

The derived order is stated once at session start, and it is the receipt to check when in doubt:

enabled: 4 of 13 mod(s), in load order — ironlark:badgrass@0.1.0, ironlark:freeroam@0.1.0, acme:chat@1.0.0, acme:shop@1.0.0

When the set cannot be resolved

The whole resolution fails rather than quietly skipping a name. A session missing a mod you asked for is not the session you configured, and finding that out from a missing door an hour later is worse than not starting.

Naming something that is not installed:

this session's mods cannot be resolved:
  'acme:chat' is not installed; named in the session's mod list
Install a version every requirer accepts, or remove the mods that need it from the session's mod list.

A version no requirer accepts — one installed version exists per mod, so two mods that disagree about it cannot both be satisfied, and the refusal names every side:

this session's mods cannot be resolved:
  'bree:text' is installed at 1.2.0
    'acme:chat' needs '^1' (match)
    'acme:shop' needs '^3' (no match)
Install a version every requirer accepts, or remove the mods that need it from the session's mod list.

Every violation is reported in one message, so one restart fixes all of them instead of revealing them one at a time. Two mods that need each other in a cycle are also a refusal, naming the whole cycle.

Every player needs what the session runs

The host resolves the set once and announces it — each mod with the exact version it runs. A joining player runs what the host announced, matched against their own disk; their own [session] list has no say in someone else’s session. A player missing a mod, or holding it at a different version, is refused and told which — the exact text is on Diagnose a failed join.

There is no partial join, deliberately: the content they lack would simply be absent from the world around them, and a player who cannot see the doors everyone else walks through is in a worse state than one who was turned away.

So the set you enable is the set every player must install, at the versions you run. Keep it small until you have a way to hand people content.