Server mods get interface world: get-block(dimension, x, y, z) reads a
loaded chunk's block state as "minecraft:oak_log[axis=y]", get-biome its
biome ("minecraft:plains"), and
set-blocks(dimension, changes) sets up to 4096 blocks per call, checked at
once, made as /setblock makes them (place_state: neighbours, light, block
entities, every client told through the block log) after the call, before
that dimension's next tick.
Reads cost no copy: for a mod call the game lends Mods the levels' chunk
maps (moved out with mem::take and put back after), only while a running
mod has world. Writes for a level that isn't ticking (another dimension,
in-frame) wait for it, up to 65,536.
Test scripts get blocks (setup) and expect.blocks; cargo horizon-mod check
reports a trial run's block writes. Example beacons: /beacon builds a
glowstone pillar beside the player, /ground reads the block underfoot and the biome.
parse_state is now a free function so the mod path shares it.
Docs: docs/mods.md (the capability, script keys), docs/api/mods.md and the
regenerated reference.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A server mod runs where the world is simulated. Its manifest says side =
"server" and api = "0.3" (only a server mod may), and its component targets
the new WIT world horizon-server-mod:
- imports log and storage as client mods do, and the new capability players:
online() (id, name, position, dimension, game mode, health), tell(id, text),
broadcast(text), 8 lines per call shared with chat;
- exports server-events: init, tick, player-joined, player-left, chat, command
(with the player who typed it; its feedback goes back to that player),
block-broken and block-placed (with the block state as text).
horizon-mods: a second bindgen world sharing log and storage with the first;
a running mod holds either kind of hooks; Mods::load_for(Runs) starts only the
mods a game runs (the window client mods, the world's server server mods,
in-frame single player both) and marks the others Elsewhere. Client and server
commands are owned separately. The game passes Runs::Client for now, so
nothing changes in game until its server code calls these hooks.
The SDK gains horizon_mod_sdk::server (ServerMod, Registration,
export_server_mod!), the example server mod welcome (greets, announces
newcomers kept in storage, /online, /mined), and cargo horizon-mod check's
trial run plays a server mod with a player joining, chatting, typing its
commands and leaving. The manifest refuses client capabilities on a server
mod and players on a client mod. The generated reference, the guide, the
portal and the stability table describe it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
docs/api/mods-reference.md lists every capability, world, interface, type,
function and hook of horizon:mods, generated from
crates/horizon-mod-sdk/wit/horizon.wit and the manifest's capabilities by a
test in horizon-mods (feature pack, as CI runs it). The test fails when the
page is out of date (HORIZON_WRITE_DOCS=1 rewrites it), when a function has
no doc comment, or when a capability grants an interface the contract lacks.
The WIT's undocumented functions and fields get doc comments (no change to
the contract itself).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ludovic Marie