docs/modules/rust-dryrun.md

module-rust — a dry run

Phase 3's fourth acceptance criterion (../website/MODULE_SYSTEM.md §2.7). A written design for a module serving a Rust (Facepunch) community, taken far enough to find out whether the contract generalises past the game it was extracted from — and deliberately not implemented. A contract validated only against the module it was carved out of has not been validated.

The exercise is honest if it finds something. It found four things, one of which is a gap in the contract that a real second module would hit on its first day. They are in Findings at the end; the design comes first, because a finding is only worth anything with the design that produced it.

Rust was chosen because it is unlike Ultima Online in the ways most likely to break assumptions: it wipes every month, a community runs several servers rather than one shard, its identity is Steam, and its server is not source you can compile — ServUO's overlay is C# a shard owner builds into their own server, and a Rust server is a binary nobody outside Facepunch patches. The way in is a mod: a plugin loaded by the server's mod framework, hooking the game's own events. If the contract survives that, "game-agnostic" means something.

Nothing here re-specifies the contract. ../website/MODULE_API.md is normative; this document only uses it.

Revisited 2026-08-19, for Teams (MODULE_API_VERSION 1.6.0, Teams phase 11). A Rust team is a Team, so the design grew a provider and an inverted slot — the two places the contract changed since this was written. Everything else stands, including all four findings: the identity gap is still open and still the one a real second module hits first.

---

1. The manifest

{
  "id": "rust",
  "name": "Rust",
  "version": "0.1.0",
  "coreApi": "^1.5.0",
  "server": "server/index.js",
  "client": { "entry": "client/dist/entry.js" },
  "schema": "server/db/schema.sql",
  "purge": "server/db/purge.sql",
  "mounts": {
    "public": ["/rust"],
    "admin": ["/rust"],
    "player": ["/rust"]
  },
  "extensions": ["admin.users.detail"],
  "capabilities": ["servers", "wipes", "leaderboards", "map", "killfeed", "teams"]
}

Correction, 2026-08-12. coreApi read ^1.3.0 here until the Integration Kit's acceptance run (kit-acceptance.md) found it. The contract was at 1.3.0 when this design was written and has moved twice since; the number is now ^1.5.0. Left as a correction rather than a silent edit because why it went stale is the reusable part: this is the only complete module.json in the kit's reading path, so it is what a newcomer copies — and unlike the template, which CI holds against core's MODULE_API_VERSION on every pull request (../website/MODULE_SYSTEM.md §2.11.1 d2), a JSON block inside a Markdown document has nothing checking it. A range is also the shape least likely to be noticed when it rots: ^1.3.0 is satisfied by a 1.5.0 core, so a module copied from here would have loaded fine and simply been wrong about what it was written against.

One prefix per tier, named for the module rather than for a feature — the opposite of module-uo's /shard + /atlas + /uo-link, and the better choice for anything new. Module-uo's prefixes are what they are because §1.2 froze the URLs core already served; a module written today has no such debt and should claim one obvious segment. It also sidesteps the collision surface entirely: /shard is a word a second game might want, /rust is not.

2. The server half

module.exports = function register(ctx, api) {
  core.init(ctx)

  const publicRouter = require('./router/public/rust.router')
  const adminRouter  = require('./router/admin/rust.router')
  const playerRouter = require('./router/player/rust.router')
  const userExt      = require('./router/admin/usersRust.router')

  api.registerRoutes({
    public: { '/rust': publicRouter },
    admin:  { '/rust': adminRouter },
    player: { '/rust': playerRouter },
  })

  api.registerExtension('admin.users.detail', userExt)

  api.registerNotificationStreams([
    { id: 'rust.wipe', label: 'Server wipes',
      description: 'A server wiped — new map, new seed, everything reset.',
      personal: false, requiresLinkedAccount: false },
    { id: 'rust.raid', label: 'Base raided',
      description: 'Your base took damage while you were offline.',
      personal: true, requiresLinkedAccount: true },
  ])

  api.registerAnnounceLeg({
    leg: 'rust.ingame',
    label: 'In-game chat',
    dispatch: (post) => link.command('chat.broadcast', { text: `[NEWS] ${post.title} — ${ctx.site.baseUrl}/news/${post.slug}` }),
    classify: (result) => (result.ok ? { outcome: 'done' } : { outcome: 'retry', error: result.error }),
  })

  // Teams (1.6.0). A Rust "team" is a Team: core owns the tables, the membership
  // sync, the access rules, the forum and the activity feed; this module owns the
  // word and the roster behind it.
  api.registerTeamProvider(teamProvider)

  api.onBoot(async () => { await link.connect() })
  api.onShutdown(async () => { await link.close() })
}

Everything above is a call the contract already has, used the way module-uo uses it. Three details are worth pointing at:

• rust.wipe and rust.raid are namespaced, with no grandfathering request. Module-uo's seven bare stream ids are allowlisted because they were in notification_subs before the rule existed (§6.5); a new module gets the rule, and the rule is exactly right.
• The announce leg goes to in-game chat, by asking the sidecar to send a command down the socket the mod already holds — a one-shot delivery with retry, so registerAnnounceLeg and not registerPostHook. The distinction §2.4 draws holds up on a game that has nothing in common with the one it was drawn for. Note the direction: the module never speaks to a game server, and the sidecar never dials one either — it answers on a connection the mod opened.
• The Team provider is the one registration core calls back into, and Rust makes two of its rules bite harder than UO does. externalId must survive a rename, and a Rust team has no name at all — it is a numeric team id in the server's save, which is the right answer and the one a designer is least likely to reach for. And complete is per SERVER, not per community: a community running six servers has six team spaces, so a provider that can reach five of them must leave complete off or core archives every Team on the sixth. Wipes make the same point once a month, on purpose — a wipe empties every team, and { ok: true, complete: true, teams: [] } is then true and core archiving all of them is correct. Which is exactly why a sidecar with no mod connected must answer { ok: false } instead: the two states are one API call apart and only the module can tell them apart.

Tables

rust_servers, rust_wipes, rust_players, rust_player_stats, rust_teams, rust_events, rust_bans, rust_maps. All rust_-prefixed, all in one idempotent schema.sql fragment.

rust_teams stays this module's table, and core's teams stays core's. They hold the same teams and neither reads the other: the module ingests from the sidecar into rust_teams, core reconciles by asking the provider, and §2.6's prefix rule forbids the module touching core's table even though the module is what populates it. A module that wrote team_members directly would be racing core's reconciler for rows it does not own.

Every table that holds gameplay data carries a wipe_id. That is the whole shape of the game in one column: a leaderboard means "since the last wipe", a base means "on this map", and a player's stats are per-wipe with an all-time rollup kept separately. It has no bearing on the contract — core replays the fragment and never looks inside — but it is the first thing a UO-shaped mental model gets wrong, and it is worth writing down for whoever builds this.

Talking to the game

A mod, a sidecar, and the same three-part shape UO has. Rust's server is a binary, so there is no overlay to compile into it and no source to patch — but it loads mods, and a mod is C# with a hook for everything this design needs. So rust-link is a real sidecar rather than a wrapper around an admin channel, and it is fed the way uo-link is fed:

Rust server + rust-bridge mod (C#, hooks)
   │  loopback TCP, newline-delimited JSON, bidirectional
   │  the MOD dials out to the sidecar — the game opens no listening port
   ▼
rust-link sidecar
   │  bearer-authed HTTP + WebSocket, versioned
   ▼
module-rust, inside the website

The mod is the interesting half, and it is where a UO-shaped model has the least to unlearn. The threading contract transfers whole — emit enqueues onto a bounded drop-oldest queue and returns, one writer thread owns the socket, the world is read only on the game's own thread — because it is a property of game servers and not of ServUO. What changes is that the hooks are handed to you rather than found: the mod framework publishes them, so the plugin is small and the guesswork is in deciding what to emit rather than in finding somewhere to hang it.

Two of them answer questions UO had to work for:

• The wipe arrives as an event. The mod is told a new save has begun; nothing has to detect a wipe by noticing the world looks different.
• Membership is real-time — created, joined, left, disbanded, leader changed. UO has no guild.leave at all and needed a 60-second sweep plus a set diff to synthesise one (protocol 4, ../link/v4.md); here every transition is delivered as it happens. So this module's Team provider is event-driven with a baseline on connect rather than sweep-driven — and the provider contract does not change by one line, because core asks the same three questions and gets the same envelope. That is the result worth keeping: the contract never needed to know how the data arrives.

The sidecar still earns its place, and the store is why. A hook fires once, and what it says while nobody is listening is gone. So the sidecar appends every kill, wipe and chat line, keeps the latest snapshot of each server's state, and answers the website's reads from disk — a website that is down, restarting or mid-deploy loses nothing, and a leaderboard renders the last thing the server said rather than an error. It also keeps the auth token, the reconnect loop and the per-server fan-out out of an Express process, where a stalled socket is a stalled request handler.

Several servers, one sidecar. Each server runs the mod and each dials the same sidecar, identifying itself on connect; the sidecar keys every board by server id. A community running six servers deploys one thing per server and one sidecar, and the module sees a single API — which is where the Team provider's per-server complete (§2) gets its meaning.

wipe_id makes the durable copy load-bearing rather than a nicety. A wipe is the moment the game forgets; the sidecar is the only thing that remembers the shape of the map that just ended.

Commands go back down the same socket. The announce leg's in-game chat line is a command the sidecar sends to the mod — the same direction UO's bridge already carries. The connection belongs to the mod, and nothing outside the game ever dials into it.

Correction, 2026-08-12. This section originally concluded "No sidecar" — the module dialling RCON directly — and offered it as evidence that core has no opinion about how a module reaches its game. That was overruled by the org lead when Phase 5 (§2.11.1 d3/d4) settled the kit's stance, and the prohibition is now contract: ../website/MODULE_API.md §2.7, as of MODULE_API_VERSION 1.4.0, a module does not open a connection to a game server from the website process. The original reasoning was not wrong about ServUO — the shard-dials-out invariant in ../link/PLAN.md really is a property of an engine with no remote-control surface — but it mistook that for the whole reason a sidecar exists. The other reason is durability: the website is not the right place to hold a game connection, because it is the process most likely to be restarted and the one facing the internet. The finding is left in view rather than edited out; what a dry run concluded is worth more than a tidy document.

Correction, 2026-08-19 (org lead). This document originally reached the game over RCON, and this section concluded "a thin sidecar" on that basis — no wire protocol to invent and no game-side plugin to write. Overruled: the transport is a mod, exactly as it is for UO, and RCON is not used. Hooks inside the mod expose the data and the mod dials the sidecar.

Two things that costs the document, worth stating because both were used as evidence elsewhere. Rust is no longer an example of "a game that already speaks a remote-control protocol, so its sidecar is thin" — that example now has none in this project. And the reason Rust is a good second game is no longer that its protocol comes free. It is that its server is a binary, the opposite of ServUO: the way in is a published mod API rather than source you compile, and the shard-dials-out invariant has to survive that change of footing. It does, unchanged, which is a stronger result than the one this document originally claimed.

3. The client half

registry.registerRoutes('rust', {
  public: [
    { path: 'servers',            element: <Servers /> },
    { path: 'servers/:id',        element: <ServerDetail /> },
    { path: 'servers/:id/map',    element: <MapView /> },
    { path: 'leaderboards',       element: <Leaderboards /> },
    { path: 'wipes',              element: <WipeSchedule /> },
  ],
  player: [
    { path: 'account',            element: <LinkedAccount /> },
    { path: 'stats',              element: <MyStats /> },
  ],
  admin: [
    { path: 'servers',            element: <AdminServers />, gate: { roles: ['admin'] } },
    { path: 'ops',                element: <AdminOps />,     gate: { roles: ['admin', 'moderator'] } },
  ],
})

registry.registerNav('rust', {
  area: 'public',
  items: [
    { label: 'Servers',      to: '/rust/servers',      group: 'Play',  order: 10, icon: ServerIcon },
    { label: 'Leaderboards', to: '/rust/leaderboards', group: 'Play',  order: 20, icon: TrophyIcon,
      feature: 'leaderboards' },
    { label: 'Wipe schedule', to: '/rust/wipes',       group: 'Play',  order: 30, icon: CalendarIcon },
  ],
})

registry.registerFeatureProvider('rust', 'rust', useRustFeatures)
registry.registerExtension('rust', 'admin.users.detail', LinkedSteamAccounts)

// The INVERTED direction (1.6.0): this module declares places on its OWN team
// page and core fills them. Core publishes no team page — it does not own the
// word — so `/rust/servers/:id/teams/:teamId` is this module's, and core's feed
// and forum are contributed into it.
registry.declareModuleSlot('rust', 'rust.team.detail', { core: 'team.activity' })
registry.declareModuleSlot('rust', 'rust.team.forum', { core: 'team.forum' })

Play is a group core does not have; §3.3 appends an unknown group rather than dropping the items, so this works and lands at the end of the nav — where an operator can move it, because a module row is an ordinary row once it is interleaved.

The pages need PublicLayout, PageHeader, the three PageState components, useAsync and useAuth: six of the kit's nine members, plus useSite on the wipe-schedule page for the site's timezone and Slot on the team page. A second game, unrelated to the first, wanting exactly what the kit contains is the strongest evidence available that §3.4 was curated at the right altitude.

The team route carries a server id as well as a team id, which is the Rust-shaped consequence of the finding two sections down: team 4 on one server and team 4 on another are different teams, so the module's externalId has to be <serverId>:<teamId> and its page needs both. Core stores that string and never parses it — an external id is opaque to core by design, and this is the case that shows why.

The map view is the one page that wants something the kit does not have — a pan/zoom canvas. It bundles one, which is the answer §3.4 already gives ("everything else a module bundles itself"), and it costs the chunk about 40 KB.

---

Findings

1. A module cannot register an identity provider — and Rust's identity is Steam

The gap. Module-uo proves account ownership with an in-game [link command that issues a one-time code; the website confirms it with the sidecar. Nothing about that needs core's auth layer, so nothing in api ever needed to touch it.

Rust's answer is Steam OpenID, and every Rust community expects "Sign in with Steam". Core has an SSO layer — authProviders, userIdentities, OAuth2/OIDC providers behind a registry — and MODULE_API.md §2.4 offers a module no way in. There is no registerAuthProvider, and §2.7 forbids reaching for one.

A Rust module can still ship: it can copy the UO shape, issuing a code in-game and matching it on the website. That works, it is one screen worse, and it leaves the community's obvious expectation unmet.

This is not a defect in what was built — it is the boundary of what was specified, found exactly where a dry run is supposed to find it. It is worth stating precisely, because whoever adds it has to answer a question the current policy already has an opinion about: SSO is link-only by design, an external identity must already be linked to an existing account, and identities are never auto-provisioned. A Steam provider a module registers must inherit that, not route around it. It is also not a small addition: an identity provider participates in session creation, which is the one part of core a module must never be able to weaken.

Recommendation: leave it out of v1 of the contract and record it here as the first candidate for MODULE_API_VERSION 1.4 or 2.0, specified deliberately rather than bolted on when someone needs it.

2. "One module, one game" is not the same as "one module, one server"

A UO community runs one shard. A Rust community runs four or five, wipes them on different schedules, and every page is a per-server view.

The contract is silent on this, and silence turns out to be right: multiplicity lives entirely in the module's own tables and route parameters (/rust/servers/:id). Core's mount prefixes, capabilities and state machine are per-module, and none of them wanted to be per-server.

Worth recording only because it looks like a problem until you try it — and because it is the shape that would have broken a contract designed around "the shard" as a singular noun. The phase-2 inversions that removed core's opinions about game content (the push catalog, the announce legs, mapEvent dropped) are why it does not.

3. The event catalog generalises; the retention assumption does not

rust_events is the twin of shard_events, and the ingest shape carries over unchanged.

What does not carry over is that a UO event log grows forever while a Rust one is truncated every wipe. That is module-internal — but it lands on something core does own: the schema fragment must not be where that truncation happens. §2.6's leading-verb allowlist (CREATE, ALTER, INSERT, UPDATE) already forbids DELETE and TRUNCATE in a fragment, precisely because the fragment is replayed on every boot and would empty the table each restart.

So a wipe is a runtime operation on a module route, not a schema one. The allowlist was written for a different reason — the phase-2 note says "the file replays every boot, so TRUNCATE/DELETE would empty a table each restart" — and it correctly forbids the first mistake this module's author would make. A rule that catches a case it was not written for is a rule at the right altitude.

4. capabilities earns its keep the moment there are two modules

With one module, capabilities reads like decoration — core never interprets one, and the SPA knows what it registered. With two, it is the only thing a client can ask.

The Android app is the case: it feature-detects against GET /api/v1/public/modules and must render a site whose module it has never heard of. ["servers", "wipes", "leaderboards"] tells it there is nothing shard-shaped here without it having to know what rust means, and §2.9's rule — treat an unknown capability as absent, never infer a route from one — is what keeps that from becoming a second, worse route table.

No change needed. Recorded because the design decision looked over-engineered with one module and is load-bearing with two.

---

Verdict

The contract generalises. A second game, chosen for how little it shares with the first, is served by the same module.json, the same registration calls, the same schema-fragment rules, the same client registry and the same UI kit — with one genuine gap (identity providers), one non-issue that looks like a gap (multiple servers), and two places where a rule written for one reason turns out to cover another.

And the three-part shape generalises with it, which the 2026-08-19 correction is what actually established: a game whose server is a binary, reached through a published mod API, still ends up with a plugin that dials out, a sidecar that persists before it forwards, and a module that talks only to the sidecar. Nothing about that arrangement was a property of ServUO being source you can compile.

The gap is worth having found before something was built on top of it, which is what a dry run is for. What it does not establish is that someone outside this org could build this module from the documentation alone — that is the Integration Kit's acceptance test (§2.11), and it stays untested until a person who did not write any of this does it.