CyberRunner

A browser multiplayer FPS. The server owns movement and hits. ArenaForge is a level-design agent that edits a map you can then play in the same runtime.

Play: game.cyberrunnergame.dev

Guest play works. Two tabs can share a Deathmatch with the 6-letter HUD code.

What this is

The server runs movement and hits at a fixed 60 Hz RAPIER tick. The client predicts locally, reconciles on each ack, and fires through a bounded rewind window.

Draw an arena boundary, place the starting positions, and give ArenaForge a brief. The agent publishes a plan, builds the map through bounded level-editing tools, reads deterministic gameplay checks, and can revise before the result is saved and launched in CyberRunner.

Search & Destroy and Deathmatch are both supported. Playing a saved map does not call a model.

Gameplay

• Public map: Shoot House Neon
• Deathmatch: first to 5 kills, 10 minutes
• Search & Destroy: 3 lives, first to 3 rounds, spike plant and defuse
• Eight weapons, hitscan and projectile
• Crouch, prone, slide, sprint
• Quick Play and hosted rooms

map-contract-smoke is an internal fixture. It is not in the Create Game picker.

ArenaForge

Open Arena Forge in the lobby.

• Recorded Design replays a complete native S&D design from a blank user-defined arena, including the plan, construction, deterministic checks, route inspection, playtest feedback, and revision. It runs without a model key.
• New Design is the live product path: mouse-draw a rectangle, place starts, write a brief, Generate.

Saved maps show up in Create Game as FORGE · <name>. Quick Play stays official maps only.

Human design setup
      ↓
ArenaForge agent
      ↓
ArenaMap
      ↓
evaluator / scripted playtest
      ↓
GameplayMapDefinition
      ↓
 ┌───────────────┐
 │               │
Play now       Save
 │               │
Room          Postgres
                 ↓
              Lobby
                 ↓
               Room

To run live design on your machine, put an OpenAI or Anthropic key on the server. See docs/arena-forge-live.md. Guests can Save Map for the current session. Keeping maps on a profile needs Postgres and a signed-in user. The public site keeps live design off unless you turn it on with sign-in and daily caps.

Recorded Design is a product demonstration of the current native loop. Historical P4 and P5 runs remain evaluation and research evidence. They are not a public Forge tab.

Both historical designers solved the simple repair cases (blocked spawn, broken routes) in one edit. A harder suite, where a useful edit can break something else, did not show the iterative designer winning overall. The historical P5 session queried the playtest, overcorrected, then revised.

Numbers: server/arena-forge-evaluation.md, server/arena-forge-evaluation-p4b.md, server/arena-forge-playtest.md.

The camera flythrough is presentation only. The scripted playtest is an offline navigation proxy, not bots in a live room.

Networking

1. Client samples input on a 60 Hz tick and assigns a unique seq.
2. Local RAPIER applies that command and stores a controller snapshot.
3. The same command is sent as a 15-byte input_bin.
4. Server queues it (max 24), applies one command per sim tick, writes PlayerState, acks lastProcessedInputSeq.
5. Client restores the snapshot for that ack, applies the server pose, replays leftovers once, then smooths the camera.

Firing uses a 13-byte fire_bin. Shot origin comes from rewind history (RTT/2 plus 1.5 ticks, capped at 250 ms). Aim is client-originated and sanitized. Shared CharacterController, capsule, and shoot-house colliders live in shared/.

Measured results

From npm run benchmark on 2026-08-29 (Node v23.11.0, Windows, i9-14900KF). Raw file: benchmarks/latest.json. Method: benchmarks/README.md.

These are local synthetic numbers, not a production load test.

Item	Value	Kind
INPUT_CMD size	15 bytes	measured (encodeInputCmd)
FIRE_CMD size	13 bytes	measured (encodeFireCmd)
60 Hz input payload	900 B/s	calculated from 15 × 60
Pending inputs at 0 / 50 / 100 / 150 ms	0 / 3 / 6 / 9 ticks	synthetic local prediction harness
Tick time, 1 / 4 / 8 capsules	mean 0.017 / 0.054 / 0.151 ms	synthetic local RAPIER only

F3 in a match, or debug.overlay() in the console, shows RTT, seq/ack, pending replay, and predicted vs server pose.

Run locally

npm install
npm test
npm run dev:server    # ws://localhost:2567
npm run dev:client    # http://localhost:5173

npm run build
npm run preview

Copy server/.env.example to server/.env only if you want auth, a database, or live Forge. Guest play works without that.

Live Forge setup: docs/arena-forge-live.md. npm run forge:doctor checks configuration without calling a model.

Production (Caddy, systemd, Postgres): server/DEPLOY.md.

Tech

Layer	Choice
Render	Three.js
Physics	RAPIER 3D (WASM), client and server
Rooms	Colyseus schema sync plus binary input_bin / fire_bin
Server	Node.js, Express, optional Postgres + Google OAuth
Client build	Vite + TypeScript
Hosting	DigitalOcean, Caddy (HTTPS), systemd
Live Forge	OpenAI or Anthropic, server-side only

Limitations

• Single-region rooms. Default cap is 8 players.
• Remotes use chase-latest lerp, not a delayed snapshot buffer.
• Client prediction does not collide with other players.
• Hitscan rewinds. Projectiles use current poses.
• Aim direction is client-trusted after a sanity check.
• Live design is one active job per process. Saving personal maps needs Postgres and a signed-in profile.

The source is public to read. It is not open source. See LICENSE. Shipped media: ASSETS.md.