# The generation prompt pack Paste **§2 verbatim** into a capable coding model (Claude, Grok, GPT), with your own game idea in the `GAME BRIEF` slot. Everything the model needs is either in the prompt or in the four files it names. --- ## 1. What the model must be able to read Exactly these, and nothing else: | file | why | |---|---| | `docs/STACK.md` | the contract guide. Complete on its own; assumes no prior knowledge. | | `docs/PACKS.md` | ⭐ the default medium — physics, movement, camera. **Hand this over whenever the game has solids, a character to embody, or a follow camera.** Skip it only for a game whose own simple motion is genuinely enough. | | `scaffold/` | the code it builds into. `src/substrate.js` is copied in unchanged; the other four files are worked examples of every contract. | | `tools/verify.mjs` | the checker it runs on its own output. | | `docs/CHECKLIST.md` | the self-check it works through before saying it is done. | If the model has this `product/` folder open as the workspace, **that is the whole answer**. Also read `BRIEF.md` at the product root for the game to build. ⚠️ **Do not paste `SUBSTRATE.md`, `STATE.md` or `PROTOCOL.md`.** Those are written for people maintaining DevTune, and they discuss failures, history and open questions that a model building a game will read as instructions. --- ## 2. The prompt > --- > > # Build a three.js game that is born owned > > You are building a genuinely playable three.js game **with the DevTune product pack** (this > folder), so a designer can tune its feel the moment it boots — no reverse-engineering afterwards. > Follow **BRIEF.md** for the game design. > > ## Read first > > 1. **`docs/STACK.md`** — the contract guide. It is complete; read all of it before writing code. > 2. **`docs/PACKS.md`** — the default medium. If the game has solids, a character, or a follow > camera, build through the physics / movement / camera packs rather than hand-rolling them. > ⚠️ Its first rule decides whether any of it is tunable: **declare each pack's tune at YOUR call > site and pass it in.** A pack that builds its own settings produces values the desk never sees. > 3. **`scaffold/src/player.js`, `world.js`, `motes.js`, `main.js`** — worked examples of every > contract. Match their shape. > > ## Start from the scaffold > > Copy `scaffold/` to `games/horizon-courier/` (or the name in BRIEF.md). Then: > > - **`src/substrate.js` is copied in UNCHANGED.** Do not edit it. Do not reimplement it. > - **`index.html`** — keep the `?pump` script block and the three.js `0.160.0` importmap exactly as > they are. Change the title, the HUD and the styling freely. > - Everything else is yours to rewrite, extend or delete. > > ## GAME BRIEF > > ``` > {{ describe the game here — genre, the one thing the player does, win/lose if any }} > ``` > > ## Non-negotiable requirements > > 1. **It is playable.** A person can pick it up, understand the controls in five seconds, and have > something to do. Not a scene with a camera orbiting it. > 2. **At least one movement/feel system is owned and live** — read from the settings object every > frame, so a dial is felt immediately. > 3. **At least one system is deferred** (`readAt: 'spawn'` or `'nextWave'`) **if the game genuinely > has that boundary.** If it does not, do not invent one — say so instead. > 4. **The game's own colliders are handed over with `collide()`**, and exactly one piece of code > owns each overlap. > 5. **Authored ranges only where you mean them.** `[min, max]` is a design statement about what a > designer may scrub between. Where you have no real opinion, leave it off — the desk says > `NO RANGE DECLARED`, which is honest. **Never write a range to make the UI look nicer.** > 6. **Own inputs, never outputs.** A velocity, a current hp, a computed distance are outputs. Own > the numbers they are computed *from*. > 7. **No central config object.** Each system declares its own numbers in its own file, as a literal > at the call site. A shared `CONFIG` that other files import from puts every value one hop away > from the literal, and a value one hop away can be owned and cannot be saved. > 8. **The game runs with DevTune absent.** `substrate.js`'s contracts are identity functions when > nothing is attached; if the game needs them to *do* something, the design is wrong. > 9. **Do not use `C` as a game key.** It opens the Design desk. > > ## Check your own work > > ```bash > npx devtune verify games/ > npx devtune smoke games/ > ``` > > **`✓ BORN OWNED` (verify) and `✓ SMOKE PASS` are both required.** Verify alone can be green while > the game cannot boot under serve (Horizon F6). Every verify rule is a SILENT failure at runtime — > the game plays perfectly and the desk is empty, or full of dials that do nothing. Do not skip > either gate, and do not talk yourself past a fatal. Two fatals that burned Horizon: > **`bind-mega-group`** (never `bind` the parent Group that holds the world) and > **`import-outside-serve`** (pack imports must resolve under the game or product/medium|vendor mounts). > > Then work through **`docs/CHECKLIST.md`** and answer every line honestly. Where something is not > done, say it is not done — a false green here is worse than a gap, because the whole point of this > tool is that what it tells a designer is true. > > ## When you report > > Say what you built, which systems are owned, which values are live and which are deferred, what > the checker said, and **what you could not own and why**. That last one is the most useful thing > you can report. > > --- --- ## 3. Running what comes back From **`product/`** (preferred): ```powershell .\start-desk.ps1 -Game ``` Or from monorepo root (parent of `product/`): ```bash node product/tools/battery.mjs product/games/ # verify + smoke + doctor node bridge/bridge-server.js node adapters/serve/serve.mjs product/games/ --port 5430 --shell ``` Open `http://127.0.0.1:5430/`, play it, press **`C`** for Design. Full walkthrough: [`../README.md`](../README.md) · desk path + red gates: [`../RUN.md`](../RUN.md). --- ## 4. Notes on prompting, from actually doing it - **Give the model a real game idea, not a genre.** "A small action game" produces a tech demo. "You are a courier on a rooftop; deliver parcels before the timer, wind pushes you" produces a game with feel systems worth owning. - **The brief decides whether `readAt` is honest.** A game with no spawn boundary and no waves has nothing deferred, and a model that invents one to satisfy a checklist has broken rule 3. If you want the deferred path exercised, put a spawner or a wave in the brief. - **Let it choose its own ids.** Namespacing (`weapon.rifle`) is in the guide; a model that picks its own names picks names that match its own code, which is the point. - **Expect the checker to catch something.** It has, every time so far. That is the pipeline working, not the model failing.