# data (asset type) A `.data` instance is a configured value binding to a `dataType` contract: `values.yaml` names the contract and supplies the field values the contract's schema declares. Instances carry values only — structure (field types, constraints, defaults) and behavior live on the bound contract, never on the instance. Think of it as the ScriptableObject *asset* to `dataType`'s ScriptableObject *class*. ## When to use one - You have a `dataType` contract (e.g. `weapon`, `questObjective`) and need one or more concrete, named configurations of it (`smg`, `rifle`, `sniper`). - You want the configuration to persist as authored content, discovered by `asset.list("data")` / `contractType:instances()`, and validated against the contract on every edit. - Mutable *runtime* state (ammo remaining, cooldown timers) belongs on a component, not here — a `.data` instance is configuration, not simulation state. If you don't have a contract yet, author one first (`asset.create("dataType", ...)`). ## Where it lives - Source: `/zero/source/.../<Name>.data/` - Identity: `<Name>` (the `.data` suffix strips). - Folder shape: - `values.yaml` — `contract: <dataTypeName>` plus a `values:` map of the contract's fields. **Required.** - `.metadata` — description + tags for search. **Required.** Play-mode edits fork a runtime copy (`runtime_copy: true`) — tweaking values while gameplay runs never writes back to the source instance. ## How to create one ```luau asset.create("data", "<Name>", { contract = "<dataTypeName>" }) -- Creates: /zero/source/<Name>.data/ -- values.yaml (contract binding + the contract's declared defaults) -- .metadata (empty description/tags — fill both to publish) ``` `opts.contract` is required — creating without it, or naming a contract that isn't a registered `dataType`, errors loudly and names `contract` in the message. The seeded `values.yaml` fills every field the contract declares a default for, so a fresh instance is immediately valid wherever every required field has a default. ## Ref surface (`AssetRef<data>`) - `ref:contract()` — the bound `AssetRef<dataType>`. - `ref:satisfies(wanted)` — `(ok, reason?)`: whether this instance's contract chain includes `wanted` (the bound contract itself, or any contract it extends). `reason` is a string explaining a `false` result (unrelated contract, unresolvable binding, invalid values). - `ref:validate()` — `(ok, violations)` against the bound contract's merged schema. `violations` is an array of `{ path, message }`. - `ref:data(wanted?)` — the resolved, read-only value object: this instance's `values.yaml` with the bound contract's schema defaults filled in, `assetRef` / `dataRef` fields materialized (`assetRef` → `AssetRef`, `dataRef` → a nested value object resolved the same way), and the bound contract chain's `behavior.luau` methods reachable by field-style call — `v:someMethod()` alongside `v.someField`. Method resolution is **child-first**: the bound contract's own methods win over an inherited one of the same name, and either loses to an explicit instance value of that name (values always shadow methods). A contract with no `behavior.luau` simply contributes no methods — it still inherits its ancestors' via the chain. Pass `wanted` to assert the instance's bound contract satisfies that contract before resolving (same semantics as `:satisfies`) — it's an assertion of intent, not a filter: the returned object still carries the full bound schema and full method chain, not a view scoped to `wanted`. Raises when the instance's values violate its contract (same violations `:validate()` reports), when `wanted` doesn't appear in the bound contract's chain, and when `dataRef` fields form a circular chain (instance A referencing B referencing A). The object is read-only at the top level — assigning a field raises; change configuration by editing `values.yaml` instead. Nested plain tables (struct and array values) are private copies of the resolved snapshot: mutating them changes only your snapshot, never the source instance or any other caller's resolve. Generalized iteration (`for k, v in w do`) walks the resolved value fields (explicit values + filled defaults); methods are reachable by name but never appear in iteration. ```luau local w = smg:data() -- resolved value object print(w.damage, w.fireMode) -- schema values (with defaults) print(w:dps()) -- a behavior.luau method, if the contract ships one local weapon = smg:data("weapon") -- asserts smg's contract chain includes "weapon" ``` ## Discovery - `asset.list("data")` — every registered instance, as `AssetRef`s. - `<contractRef>:instances()` — every `.data` instance bound to that contract or to a contract that extends it (see `dataType`'s ref surface). - `asset.inspect("<name>")` — the instance's files, bound contract, values, and this type README. - `ls /zero/source/<Name>.data` lists the files the folder holds. ## Authoring conventions - Name instances for the specific thing they configure (`smg`, `rifle`), not for the contract they bind (that's `values.yaml::contract`). - Keep `values.yaml` limited to configuration; anything that changes during gameplay belongs on a component instead. - Say what this specific configuration is tuned for in the `description` of its `.metadata` — the contract's own README documents field meaning. ## Common pitfalls - **Missing or unknown contract at creation.** `opts.contract` must name an existing `dataType`; both a missing `opts` and an unknown contract name error before any file is written. - **Values drifting from the contract.** Editing `values.yaml` re-runs validation immediately; a violation warns rather than silently passing through. - **Confusing configuration with runtime state.** A `.data` instance never mutates during play — components own live state. ## Related types - `.dataType` — the contract this instance is bound to; owns structure, validation, and (optional) behavior. - `.preset` — a named set of values for one declarer's settings schema (an assetType, an importer, a component), not a contract of its own. ## In the Inspector Values: a link to the contract this instance is bound to, every contract field as a typed control (`data_schema`'s `toFields`), and the values that break the contract. An edit is checked against the contract and written through `dataRef:setValues`, one undoable step. `setValues` re-encodes values.yaml with `Yaml.encode`, so comments in the file are not kept; a values.yaml that carries comments is therefore shown read-only, with **Open** for the file. `dataRef:setValues(patch)` replaces the named top-level fields and checks the result against the contract. A change is refused (one error naming each violation, nothing written) when it introduces a violation or leaves one standing at or under a value it set. A list item is known by what it holds rather than where it sits, so removing or reordering items sets none of the rest. A violation the file already held anywhere else stays listed and does not stop the change, so an instance that does not yet satisfy its contract fills in one field at a time, and a value beside a key the contract does not declare stays editable. It writes values.yaml, recorded into the open undo operation when there is one. An Inspector edit writes only the leaves it changed: every other value keeps its stored value and form, including a colour held as numbers, a map-form vector, and keys the contract does not declare.

# oceanPreset A complete sea state for the ocean system: everything `ocean.create` needs to stand up a specific sea, from the wave spectrum to the seabed under it. Each `.data` instance is one named preset offered in the ocean's preset list. ## Fields - `key` — the name the preset answers to in `ocean.create({ preset = ... })` and the presets API. Stable; world content refers to it. - `label` — the human-readable name shown in pickers. - `order` — the preset's slot in the calm-to-gale progression the list is offered in (1 = flattest). - `seed` — the spectrum's random seed. - `waves` — the FFT spectrum: wind speed and direction, choppiness, gravity, JONSWAP gamma, spectral sharpness, standing-wave ratio, animation speed, and a global amplitude on top. - `cascades` — the three simulation bands: per-band enable, amplitude and world-space tile scale in metres. - `gerstner` — the analytic long swell layered under the FFT bands: wavelength and its spread, amplitude, wave count, directional spread. - `clipmap` — the surface mesh: base tile size in metres and ring count. - `color` — the water column: absorption rates authored as a hex triple (decoded to per-channel 1/m extinction), transmission and body colours, and the depth assumed where nothing stands behind the water. - `fresnel` — the mirror: distance fade start/power, index-of-refraction ratio, normal strength, screen-space refraction strength. - `foam` — the three layers: `surface` lace, `waves` whitecaps (with persistence, optional `breaking` window and `placement` mask), and the `shoreline` wash. - `floor` — the procedural seabed and its `caustics` web. - `shore` — how deep the bottom starts taking the waves (`shoalDepth`, metres); omitted, the ocean's default shoaling band applies. - `sss` — subsurface scattering through backlit crests. - `ssr` — screen-space reflections. - `sparkle` — the sun's specular glint. Colour-valued fields are authored as `#rrggbb` strings and decoded to linear RGB by `Presets.color` on the way to the GPU — including `absorptionColor`, whose channels are extinction rates rather than a colour.

# assetType (asset type) The `assetType` is the **type of types** — the meta-type that every `<typename>.assetType/` folder is an instance of, including itself. A `<typename>.assetType/` folder declares a new asset type called `<typename>`: its on-disk shape, its identity rule, and the structural contract instances of the type must satisfy. This type is self-hosting. `assetType.assetType/` conforms to its own schema — a `type.yaml` plus a `README.md` — so the type system is defined in terms of itself rather than a hidden engine special-case (the same way a C compiler is written in C). Every asset in the engine, including each `.assetType` definition, now resolves to a registered assetType: a `.material` resolves to `material.assetType`, and `material.assetType` resolves to `assetType.assetType`, which resolves to itself. ## Why it exists Assets used to be mapped to their type *implicitly*, by matching the folder suffix against a name-keyed registry. That match carried no stored link: nothing on a `Foo.material` recorded *which* `material.assetType` it was written against, so two worlds shipping a same-named type could silently disagree. Making `assetType` a real, resolvable asset closes that gap — the link from an asset to its type is now an explicit reference pinned in the asset's `.refs` sidecar (`via: "asset_type"`), exactly like every other dependency. ## Where it lives - Source: `/zero/source/.../<typename>.assetType/` - Identity: `<typename>` (the `.assetType` suffix strips from the identity; the folder retains the suffix on disk). - Folder shape: - `type.yaml` — the structural spec the validator reads. **Required.** - `README.md` — type-level documentation. **Required.** - `about.yaml` — three short plain-language texts saying what the type is for (see "Say what your type is for" below). Every built-in type ships one. - `behavior.luau` — optional behavior/scaffolding module. - `template/` — optional canonical placeholder body the templater copies into a new asset of the type. - `<name>.module/` — optional shared code the type ships to **every instance** of it, conventionally `shared.module/` (see below). ## Shared code its instances reach (`asset.containing` + `.modules`) A type ships code every instance of it uses by declaring the modules in its own `behavior.luau`, as a map of tracked `require`s: ```luau -- inside <typename>.assetType/behavior.luau M.modules = { shared = require(".shared") } -- the sibling shared.module/ ``` An instance reaches it with one location-independent line: ```luau -- inside any foo.<typename>/init.luau local api = asset.containing(__FILE__).modules.shared ``` `__FILE__` is the chunk's own VFS path; `asset.containing` resolves the calling asset, and `.modules.<name>` follows the instance's pinned `typeRef` (the type's **guid**, recorded in the instance's `.refs` as `via = "asset_type"`) to the module its type declares. Because resolution follows that link rather than a category name, the same line in an instance of a different type resolves to that type's module, and identically-named modules in two types never collide. `asset.typeRef(target)` reads that guid for any target; `asset.resolve(asset.typeRef(target))` gives the full `AssetRef<assetType>`. See `assetTypes/README.md` § "Shared code: type-owned modules" for the full mechanism. ## How to create one Authoring a new asset type is just creating a `<typename>.assetType/` folder under `/zero/source/`. The engine registers `<typename>` as a category **the moment the folder is written** — no engine restart, no Rust change, and it works for built-in (`@builtin/assetTypes/`) and user-defined types identically. Once `<typename>` is registered, `<name>.<typename>/` folders are recognised as assets of that type and resolve their `asset_type` link back to this definition. Creating a `<name>.<typename>/` folder *before* its `<typename>.assetType/` exists fails fast: the suffix has no registered type, so the folder can't be a valid asset. Author the type first. ## Say what your type is for (`about.yaml`) Every type carries a small `about.yaml` beside its `type.yaml`, and the README you write for the type documents how to author an asset of it. Both are required, and both are meant to be written as you make the type, while you know what it is for. `about.yaml` answers three questions in plain words, one key each: ```yaml intent: "Sets the typeface of the text in your game: UI, labels, signs and 3D lettering." function: "A font, from a TTF, OTF or WOFF file, made available to all of Zero's text, including 3D text." usage: "You choose it by name for your UI or your text, and the text appears in that typeface." ``` - **`intent`** is what the type is for in someone's game. Name the whole range of things it covers, in the words a game maker would use for them. - **`function`** is how it works today: what an asset of the type is made of and what the engine does with it. - **`usage`** is what a person or an agent does with one: how they pick it, place it, call it, or hand it to something else. A few habits keep it useful. Write about the type as a whole, so the text holds for every asset of it, and leave out any one asset's name. Say what the type does right now. Stay with words a game maker would say, and mention a file name or a call only where a game maker would know it. The limits are in bytes: `intent` 800, `function` 1500, `usage` 1200. Each is generous, and a few sentences usually say it. Why bother: agents working in a world read these three texts to learn what your type is for, so they reach for it when it fits and use it the way you meant. People searching find the type by what they want to make, and the three texts let them tell at a glance whether it is the one they need. `asset.create("assetType", name)` scaffolds the file with all three keys, and a README whose first paragraph is a `[[describe]]` note. Each value starts with `[[describe]]` followed by a note on what to write; replace the whole value with your own words. A value or a README line that still starts with `[[describe]]` counts as not written yet, which the push's check of each asset it carries against its type reports, naming the file. A type you leave as it was is not asked, so older types stand. Many types at once, or one you would rather not write by hand: `services describe` lists the types that lack these texts and what filling them costs, and `{ mode = "all" }` writes them into the same files, where you edit them like anything else you wrote. Where the texts show up: `asset.inspect("<typename>", "assetType")` returns them as `detail.about`, `assetTypeRef:getAbout()` returns them as a table with the keys `intent`, `function` and `usage`, the type's `types/<typename>` guide page ends with an "About this type" section holding them, and the Inspector's Type section lists them at the top. The guide page is this README plus that section, so a README that explains the type well and an `about.yaml` that says what it is for read well together. ## Ask your assets to say what they are A type can ask each of its assets to carry a description: a file, written by the author or generated, that says what that asset is and what it is for. The people and agents who find an asset read it to decide whether it fits, and the author knows what it is for at the moment of making it. **1. Declare the file with a `described` check.** This is the whole requirement: ```yaml files: required: - path: "README.md" # any file name works kind: "file" content: - { check: "described", message: "Say what this widget is for and where it goes." } ``` With that in place: - An asset whose file is missing, empty, or still has a line starting with `[[describe]]` does not meet the type's requirements. `asset.validate` names it, `zm status` and `world.publishBlockers()` list it, and a push that carries it is refused with `message`. - `services describe` finds it (`mode = "find"` lists it and the price) and can write the description for it (`mode = "all"`). It writes only this file. For a YAML file that holds several texts, name the keys and their limits in bytes, the way this type does for `about.yaml`: ```yaml content: - check: "described" keys: - { key: "intent", max_bytes: 800 } - { key: "usage", max_bytes: 1200 } message: "Write intent and usage." ``` `headings` names sections a Markdown file must have. `assetTypes/README.md` has the full check. **2. Optionally, steer what gets generated with a `describe:` block:** ```yaml describe: guidance: "Say what the widget shows, what input it reacts to, and where it fits in a UI." examples: - "<identity of an asset of this type whose description reads well>" ``` `guidance` says what a description of your type covers, and `examples` names assets whose descriptions show the shape you want. Without the block, generation still works from the general describing guide and the check's `message`. An example is an asset of your type in the library whose description is a true, written one, never a scaffold's placeholder, and never the asset being described. When the library has none, leave `examples` empty rather than name one that is not. A type whose assets the model cannot perceive (a sound it cannot hear, a motion it cannot see) says so in `guidance`: the description comes only from what the asset's own files state, such as its name and the `.metadata` where a generation service records the prompt that made it, and when they state nothing the model answers `cannot` with that reason. `services describe` then fails that one asset with the reason and leaves its file as it was. **3. Start the file unwritten in your template.** Put a heading and one line that starts with `[[describe]]` and a short note on what to write, in `template/<file>`, so a new asset starts unwritten rather than with text that only looks written. Do not put example content in it: every new asset carries the template verbatim, and the same text on many assets makes them impossible to tell apart in search. Types whose assets say what they are through their own content (a mesh, a texture, a sound) leave this out: declare nothing and nothing is asked. ## The `behavior.luau` contract `behavior.luau` is the type's code. It returns ONE table, and the keys below are the ones the framework reads off it for EVERY type — the surface you get by declaring them. Anything else on the table is your own: reachable by name through `require("@builtin::assetTypes.assetType.shared.ref").loadTypeModule("<typename>")` for a system that knows your type (`computeShader` publishes `dispatchKey` that way), and never called by the framework. ```luau local M = {} M.ref = { ... } -- methods on every AssetRef of this type M.modules = { ... } -- shared code the instances reach M.global = {} -- reserved key; ship the empty table function M.onCreate(name, opts) ... end return M ``` ### The tables | Key | Shape | What the engine does with it | |-----|-------|------------------------------| | `M.ref` | `{ [name] = function(self, ...) }` | Every function becomes a method on every `AssetRef` of this type: `ref:name(...)`, with `self` the ref. This is how a type gives its instances an API. Two names in here are contracted — see below. | | `M.modules` | `{ [name] = require(".sibling") }` | Shared code the type's instances reach through `asset.containing(__FILE__).modules.<name>`, resolved by the instance's pinned `typeRef` guid. See the section above. | | `M.refShapes` | `{ [method] = "TypeName" }` | Declares the result type of a `M.ref` method so the LSP can check what a call site does with it. See the `M.refShapes` section below. | | `M.events` | an events schema | The events an ASSET of this type fires, declared the way a component declares its own. Readers subscribe through `ref.events.<name>:connect(...)`; firing authority stays with the type. Keyed by the asset's guid, so every resolver of the same asset shares the signals and a re-resolved ref re-attaches to subscriptions already there. | | `M.namePattern` | a Lua pattern string | The name shape `asset.create` enforces for instances of this type, replacing the default `^[A-Za-z][A-Za-z0-9_]*$`. | | `M.global` | `{}` | Reserved. Ship the empty table. | ### The lifecycle hooks Each is optional; a type that omits one costs nothing. The engine calls them: | Hook | Signature | When it fires | |------|-----------|---------------| | `M.onCreate` | `(name, opts) -> { [filename] = contents }` | On `asset.create("<type>", name, opts)`. Returns the files that scaffold the new instance, as a map of relative path to contents; the framework writes them. The `opts` type annotation is the schema `asset.create` validates the caller's arguments against, so annotate it. | | `M.onReplace` | `(dest, files) -> { [filename] = contents }` | On an `asset.create` that writes over an asset already at `dest`, after `onCreate`. Receives the files `onCreate` produced and returns the files to write, so a type that re-derives its content (a rig re-imported from its source file) can carry what an author added to the asset it replaces. Optional. | | `M.onRegister` | `(self)` | Once per instance, the first time it registers: on `engine.onWorldLoaded` for instances already in the world, immediately on a live `asset.create`, and when an instance arrives after that sweep (installed, pulled, or synced from a peer). Guarded by the instance's path, so a double trigger never double-registers. An instance that leaves the runtime releases the guard, so one arriving at the same path again registers. This is what makes "write an asset into the world and it takes effect live" work for content that registers into a runtime registry. The `@builtin` library is excluded from the sweep. | | `M.onChange` | `(ref, change)` | On every VFS write to a file INSIDE one of this type's instances. `change` is `{ path, asset, type, kind, origin }`: `kind` is `"edited"` or `"seeded"`, `origin` is `"local"` or `"remote"` (an importer runs on the originator only). **Filter on `change.path`**: the hook fires for any file under the folder, so act on the one you care about. It runs as its own task and may wait on what it reads: a `vfs.read` of bytes only the blob store holds (a binary file on the web build) fetches them. The writes to one asset reach the hook in the order they were made, each once the hook before it has finished. A re-entrancy guard suppresses writes back into the same asset routed inline from the hook, and a write the hook makes is routed on a later frame like any other, so the hook must be convergent on its own: diff the meaningful state and short-circuit while your own regeneration is in flight. | | `M.onDelete` | `(ref)` | When an instance of this type leaves the runtime: it is deleted, or the engine swaps away from the world binding that held it. Its files are gone from `/zero/source` by then. A removal routed while the instance's `onChange` is waiting reaches `onDelete` once that hook, and every write queued behind it, has finished. On a swap the instance still exists in the world it belongs to, and a VFS write the hook makes reaches the world now bound. | | `M.validate` | `(assetRef) -> { { code, message, severity? } }` | On `asset.validate`, after the structural `type.yaml` check, for the type's own SEMANTIC validation. `severity` defaults to `"error"`; error-severity problems flip `ok` to false, warnings do not. A hook that raises or returns a non-table is itself reported as a `validate.hook_failed` error. `world.push` runs this per user asset, so declaring it enforces your type's rules at publish time with no further wiring. | ### The two contracted `M.ref` names Most `M.ref` methods are your type's own surface: name them what you like, return what you like. Two are read by the engine and mean the same thing for every type, so their shape is fixed: - **`instantiate(self, target?, opts?) -> (root, idMap)`** — makes an instance part of the scene. Defining it is the whole opt-in: `ref:canInstantiate()` is true exactly when it exists. Its **return is a contract** — see the next section. - **`inspect(self) -> detail`** — the type-specific half of `asset.inspect`. See its section below. ### Names a type cannot shadow Some keys resolve on every `AssetRef` before per-type dispatch, so an `M.ref` entry of the same name is never reached: `canInstantiate`, `getSource` / `getBytes` / `getText`, `exists`, `deps`, `meta`, `runtime`, `events`, `modules`, `typeRef`, and the residency flags `has_backing_asset`, `has_runtime_changes`, `cpu_resident`, `gpu_resident`. These are the behaviours every asset must expose identically, which is why they win. ### Reloading A `behavior.luau` edit ripples to existing refs with no restart: dispatch reads `mod.ref` fresh each time and `require`'s cache is re-run in place. A type whose folder appears at runtime is picked up on the next dispatch — negative results are not cached either. ## The names your type's assets hold (`references:`) An asset that names another asset by a string depends on it: the named asset travels with it into a pack or a pull, and a name nothing answers to is an unresolved dependency `worldValidation` reports and the push gate refuses. The engine reads `require(...)` and the asset lookups on its own; a name your type's format or API carries anywhere else is one you declare, in `type.yaml`: ```yaml references: # A top-level key of this type's own files that holds a name (or a table of them). keys: - { key: "shader", type: "shader" } # A call's argument, counting from 1, wherever the call is written. args: - { call: "g:node", position: 2, type: "procNode" } # A field of the options table a call takes. fields: - { call: "fx.beam", field: "material", type: "material" } ``` `type` is the category the name resolves in, one of `asset.categories()`. An argument declared once per category, at the same `call` and `position`, takes the name from whichever category answers. A key or a field holds one category: declared again with another `type`, it takes the later one. The block is declared as the type registers, when the library or the world holding it is laid into the VFS, so every reference table reads it whatever script has or has not run. `asset.declareReferenceKey`, `asset.declareReferenceArg` and `asset.declareReferenceField` declare the same things from a script, for a surface that is no type's. ## What search does with your type (`indexing:`) A type declares what search embeds for its instances. **This is not optional and there is no useful default**: ZeroMind runs your declaration and adds nothing of its own, so anything you do not point at is absent from the index — silently, and for every instance of the type forever. Twenty types once shipped with no `indexing:` block and every instance of them was unfindable. A type whose instances are never searchable (a run record, a log) says so with `indexing: none`; every other type declares a recipe. A type without an `about.yaml` beside its `type.yaml` refuses every push that carries it, whether or not the push edited the type. Texts in it that are not written yet follow the rule every `described` file follows: they refuse the push that edits, stages or commits the type. Two words carry the whole thing, and they are the same two the search tool exposes: - **`identity`** — what an instance IS. For anything you can look at, that is the picture (`content:` + `modality: image`, matched directly by a text query). For everything else it is the authored text that says what it is. - **`capability`** — what it DOES and how it is made. Code, settings, the model-written summary of them. A type with no behaviour has no `capability` entry. A type with nothing to look at has no image. Leaving a slot empty is a statement; filling it with whatever happens to be lying around is not. The one you have to decide when authoring a type is: *for an instance of this, what is the thing a person would recognise it by, and what is the thing it does?* A texture answers "the image" and "its compression settings". A module answers "its README" and "its code". Write those two answers into `indexing:` and the rest follows. Three specifics worth knowing before you write one: - **`derive` is instructed by this type's own `README.md`.** A model reads an instance's source and writes a description; what it embeds is the description, not the source. It follows your README to know what it is looking at, so a type whose README says what its instances are gets good derivations for free. There is no prompt to name. - **`derive` loses detail.** It keeps the main technique and drops secondary ones. If the source is code you want searchable by its own vocabulary, declare the same files a second time as `capability` with `extractor: verbatim`. Two entries, same role, different failure modes. - **Never `source: { field: name }`.** A filename is one or two words with no usable embedding, and a corpus indexed that way answers "language runtime" with `say_runtime_2.soundClip`. `facets:` is the second stage: a `file:` embedded whole (`.metadata`, so keys nobody declared still get indexed) plus computed keys that state a value for every instance including `false` — the raw file can imply "not rigged" and can never say it. The full schema, every extractor and the facet sources are in [`assetTypes/README.md`](../README.md); the scaffolded block with inline guidance is in [`template/type.yaml`](template/type.yaml). ## A container whose contents work together (`system: true`) A type that is a container can say its contents are one working whole by declaring `system: true` at the top level of its `type.yaml`. `package` declares it: the components, modules, scenes and tools a package ships are parts of one system. The declaration is plain data, read from the decoded `type.yaml` (`require("@builtin::assetTypes.assetType.shared.declaration").of("package").system`), and a type that leaves it out is an ordinary type. ## What your type looks like (`preview:`) A type declares how its instances are pictured, and the engine makes the picture when something needs it: staging an instance whose `preview.png` is missing or pictures content it no longer holds queues a render, a view that shows the instance asks for one, and `ref:preview()` renders one on demand. An edit renders nothing on its own. Each `preview.png` records the content it pictured, which is how a stale one is told from a current one. The preview studio owns the light, the backdrop, the framing and the camera, and nothing in the world reaches it, so an instance pictures the same in every world. Declare one of four recipes: | `kind` | The picture is | Your type provides | |---|---|---| | `instantiate` | the asset stood in the studio through its own `instantiate` | `ref.instantiate` | | `image` | a file the instance holds, fitted to the frame, nothing rendered | `source.files`, the candidate files in order | | `surface` | the asset painted on a builtin mesh | `mesh`, and `ref.previewMaterial(self) -> { material }` | | `custom` | whatever `ref.preview(self, opts)` returns | `ref.preview` | ```yaml preview: kind: surface mesh: sphere ``` A scene-instantiable type that declares nothing still answers `ref:preview()` through its `instantiate`, but persists no picture: the declaration is what makes the engine keep one. List `preview.png` among the type's files so an instance may hold it. The picture is findable only when `indexing.content` names it. The two are separate statements, and neither is derived from the other: ```yaml indexing: content: - role: identity modality: image source: { file: "preview.png" } ``` `@builtin::assetTypes.assetType.shared.previewRecipe` reads the declaration; the scaffolded block with inline guidance is in [`template/type.yaml`](template/type.yaml). ## Typing a result from the instance (`M.refShapes`) Every method on `M.ref` is checked against the type its `--!return` names, and every asset of the type gets the same one. That is right for most methods and wrong for the ones whose result is shaped by the ASSET: a method answering one entry per child folder, per row of a config, per binding an input map declares. The widest true annotation for those is `{ [string]: Thing }`, and an indexer accepts every key — so a caller's typo reads as valid and nothing reports. `M.refShapes` lets the type state the result per instance. Each entry is `function(self) -> (typeExpression, source?)`: a Luau type expression for THIS asset, and the module whose type vocabulary the expression uses. Read the asset; never run it — stating a type must not take effect. ```lua -- inputMap.assetType/behavior.luau — the shipped example. -- `activate()` hands back one handle per control the map declares. M.refShapes = { activate = function(self): (string, string) local names = {} for _, control in ipairs(M.ref.controls(self)) do table.insert(names, control.name .. ": Handle") end if #names == 0 then return "", "" end return "{ " .. table.concat(names, ", ") .. " }", "@builtin::modules.zinput.scheme" end, } ``` With it, `map.jump:onPressed(fn)` resolves and `map.noexisting` is reported with the map's real controls. Without it, both pass silently. ### What the call site has to say A per-instance type is matched by the asset's IDENTITY, so it applies only where the reference the method is called on says WHICH asset. Two spellings do: ```lua -- a component field, whose declared default names the asset public = { map = Field.assetRef("inputMap", "@builtin::inputMaps.default", Sync) } local controls = public.map:activate() -- typed for THAT map -- an annotation, naming category and identity local m: AssetRef<"inputMap", "@builtin::inputMaps.default"> ``` `asset.resolve("<identity>", "<category>")` carries the CATEGORY, so the methods the category defines are checked on the result — but not which asset it found, so a per-instance result keeps the category's declared return. A reference that names no asset (`asset.resolve(someVariable)`, a value passed in as a parameter) carries neither, and calls on it are unchecked. That is the same rule everywhere: the checker states what the code states, and a name computed at runtime states nothing. ### The result is a value, not a binding The type belongs to the expression, so it travels the way any inferred type travels. Indexing the call's result is checked; stashing it in a module local and indexing it from another function is not, because the local's declared type is what carries across — and `any` (or no annotation) carries nothing: ```lua -- checked: `d.greting` is reported function awake() local d = public.dialogue:lines() d.greeting:say() end -- NOT checked: `lines` is a module local typed `any` local lines: any = nil function awake() lines = public.dialogue:lines() end function start() lines.greting:say() end ``` Bind what you need at the call site and the names stay checked in both places — the asset-derived type at the boundary, ordinary scoping after it: ```lua local lineGreeting = nil function awake() local d = public.dialogue:lines() lineGreeting = d.greeting -- `d.greting` is reported here end function start() lineGreeting:say() end ``` ### When nothing is reported and you expected something From a call site, a type that is correct and a type that was never published look the same: no diagnostic either way. `require("@builtin::assetTypes.assetType.shared.refShapes").published()` answers which it is. It returns two maps — the category surfaces, and the per-asset results keyed by identity and then by method: ```lua local shapes = require("@builtin::assetTypes.assetType.shared.refShapes").published() shapes.categories.dialogue --> "{ lines: () -> any, lineNames: () -> { string } }" shapes.returns.Shopkeeper.lines --> "{ browsing: Line, farewell: Line, greeting: Line, wares: Line }" ``` An identity absent from `returns` was never published for, which is a different thing from published-and-correct — and the reason to look here rather than at the call site. The answers are recomputed when an instance is written, so a control added to a map reaches the checker with no restart. Only types that declare `refShapes` are read per instance, and at most 64 assets of one type are — past that the type keeps its declared return and the engine log names what was dropped. ## The instantiate hook (`M.ref.instantiate`) — a contracted return A type opts into becoming part of the scene by defining `instantiate` on its `ref` table. That is the whole opt-in: `ref:canInstantiate()` is true exactly when the hook exists, so consumers offer a scene path — an `Asset.source` field, a viewport drop, a tool argument — by CAPABILITY rather than by a list of type names. Unlike `inspect`, this hook's **return is a contract**. A caller writes one piece of code against every instantiable type, so what comes back cannot vary by type: ```lua -- behavior.luau local Instantiable = require("@builtin::assetTypes.assetType.shared.instantiable") local M = {} M.ref = { instantiate = function(self, target, opts) local root = Instantiable.root(self, target, opts) -- IN: the base opts -- ... compose whatever this type is, under `root`, NOW ... return Instantiable.result(self, root, idMap) -- OUT: the contract end, } return M ``` **IN.** `target` is an owning entity ref: the instance lands under (or, for a hierarchy type, onto) that owner. With no target the type spawns a fresh root. `position`, `rotation`, `scale`, `name` and `temporary` mean the same for every type — `Instantiable.root` applies them to a root you mint, `Instantiable.place` to one you adopt, so you never re-read the spec. Honour more opts of your own if your type needs them, and document them in the hook's `--!arg` docs. **OUT.** Return `(root, idMap)` through `Instantiable.result`: - **`root`** — the composed root, as an `EntityRef`. Composition is **synchronous**: everything your type builds is live when you return, so the caller can parent to it and read its components in the same statement. Do not defer the work to a component's `awake` and return an empty shell — a root that is not live is refused. - **`idMap`** — the `originalId -> runtimeId` map naming what you spawned, or nil for a type with no addressable children (`result` normalises it to `{}`). **A caller never receives nil.** A component that re-composes your asset on every load keeps this map and passes it back in, which is how a cross-entity reference into the composition survives a reload. `AssetRef` runs every `instantiate` through `result` on the way out whether or not your type called it, so returning something else fails at your own call rather than handing a caller a nil root. Calling it yourself is still how you say what you return, and running it twice changes nothing. `@builtin::assetTypes.assetType.shared.instantiable`'s README is the full reference for both halves. ## The inspect hook (`M.ref.inspect`) `asset.inspect(ref)` resolves `ref`, builds a common envelope shared by every asset (`identity`, `name`, `guid`, `source`, `typeName`, `typeDefinitionPath`, `scope`, `origin`, `description`, `tags`), then calls the resolved type's own inspect hook — `M.ref.inspect(self)` on `behavior.luau` — for the type-specific `detail`. The hook returns *only* `detail`; the framework fills in everything else: ```lua -- behavior.luau local M = {} M.ref = { inspect = function(self) -- self.path is the asset's own folder. Parse the asset's OWN -- files — source text, a native payload header, its `.metadata` -- — never runtime state (a live component instance, a GPU -- upload, a compiled schema): inspect must work on an asset that -- hasn't been compiled, uploaded, or registered yet. return { -- type-specific fields, whatever this type wants to surface } end, } return M ``` A type that omits `M.ref.inspect` yields the generic record: the envelope alone, `detail = nil`. That's a valid, working state — not an error — but it means agents calling `asset.inspect` / `tools.use("assets","describe", ...)` on an instance of the type see only identity and scope, none of what makes an instance of it meaningful. Declaring the hook is what makes a type's instances inspectable for what they actually are. A hook that raises leaves `detail = nil` and sets `record.warning` to the error text — `asset.inspect` itself never raises for a resolved ref. ## Discovery - `asset.list("assetType")` — every registered asset type. - `asset.inspect("<typename>")` — the type's identity, source path, and this README, plus its `about.yaml` texts as `detail.about`. - `asset.resolve("<typename>", "assetType")` — the `<typename>.assetType` asset itself (used by the validator to find the type's `type.yaml`). ## Related - `assetTypes/README.md` — the full `type.yaml` schema and validator rules. - `@builtin::assetTypes.assetType.shared.instantiable` — the instantiation contract's shared implementation, both halves. - Every other `*.assetType/` here — the concrete types built on this meta-type. ## The Inspector a type ships Every type names the file its Inspector sections come from with `inspector: { type: "inspector.luau" }` in its type.yaml. `asset.create("assetType", name)` scaffolds the block and an `inspector.luau` whose Contents section lists an asset's files, built from `ctx.parts`. `asset.validate` on a type that names none reports `assetType.inspector_required` (an error for a `@builtin` type the engine's library authors; a warning for a world's own, and for one the library carries by reference, which the world that published it answers for), and one whose file does not load `assetType.inspector_invalid`. ## In the Inspector Type: what the type.yaml declares (suffix, container, primary files, the settings and inspector blocks), whether the type ships a behavior, how many instances it has, and **Open** for its files. Schema: the settings every instance carries, as read-only typed controls at their defaults (a type whose schema is per instance says where it is declared). Instances: a link to each of the first 20 assets of the type, and how many there are when there are more.

# dataType (asset type) A dataType is a user-authored typed-data contract: it declares a set of fields — names, types, constraints, defaults — that any bound `.data` instance must satisfy. A contract can carry an optional `behavior.luau` of methods its instances expose. Think of it as a ScriptableObject schema: the contract defines structure and behavior, `.data` instances supply the values. ## When to use one - You want a typed, validated configuration shape (a weapon's damage / fire mode / recoil profile, a quest's objectives, a loot table's entries) that many `.data` instances can be authored against. - You want field-level validation (required, numeric ranges, enums, references to other assets or data instances) enforced the same way everywhere the contract is used. - You want shared structure across related contracts without duplicating field declarations — `extends` factors common fields into a parent contract. If you only need a named set of values for settings something already declares, use a `.preset` instead. If you need executable shared logic rather than typed configuration, use a `.module`. ## Where it lives - Source: `/zero/source/.../<Name>.dataType/` - Identity: `<Name>` (the `.dataType` suffix strips). - Folder shape: - `schema.yaml` — the field declaration (`fields:`, optional `extends:`). **Required.** - `README.md` — instance documentation: what the contract models, what each field means. **Required.** - `.metadata` — description + tags for search. **Required.** - `behavior.luau` — optional ref methods this contract's `.data` instances expose beyond the built-in `:contract` / `:satisfies` / `:validate` surface. ## How to create one ```luau asset.create("dataType", "<Name>") -- Creates: /zero/source/<Name>.dataType/ -- schema.yaml (`fields: {}`, a valid contract with no fields yet) -- README.md (instance README template) -- .metadata (empty description/tags — fill both to publish) ``` Then edit `schema.yaml` to declare the contract's fields. ## `schema.yaml` field-spec vocabulary ```yaml extends: "item" # optional: parent contract identity fields: damage: type: number required: true min: 0 max: 100 fireMode: type: string enum: ["semi", "burst", "auto"] default: "semi" muzzle: type: vec3 default: [0, 0, 0] tint: type: color # "#rrggbb"/"#rrggbbaa" or {r,g,b[,a]} fireSound: type: assetRef assetType: soundClip # required for assetRef fields recoil: type: dataRef contract: recoilProfile # required for dataRef fields required: true falloff: type: array items: type: struct fields: distance: { type: number } multiplier: { type: number } ``` Field types: `number`, `string`, `boolean`, `vec3`, `color`, `assetRef`, `dataRef`, `array`, `struct`. - `required` — a boolean; a field with a `default` is never "missing" even when `required` is set. - `default` — must itself satisfy the field's own constraints (checked at declaration time). - `min` / `max` — apply only to `number` fields. - `enum` — apply only to scalar fields (`number` / `string` / `boolean`); the value must equal one of the listed entries. - `assetRef` — needs an `assetType`; validated against `asset.resolve(identity, assetType)`. - `dataRef` — needs a `contract`; validated against whether the referenced `.data` instance's contract chain includes it (`:satisfies`). - `array` — needs an `items` field spec every element must satisfy. - `struct` — needs a `fields` map of nested field specs; struct values reject unknown keys the same way top-level values do. ## `extends` A contract may declare `extends: "<parentContract>"` to inherit the parent's fields. The child adds new fields — it never redeclares a field the parent (or any ancestor) already declared; doing so is a schema error. Behavior is optional at every level: a contract may carry `behavior.luau` or not regardless of whether its parent does. Chains are single-inheritance and acyclic — a cycle raises loudly the moment the chain is resolved (`:schema`, `:validate`, `:defaults`, `:chain` all resolve the chain). Editing a parent's schema does not re-warn its child contracts at edit time; validation stays loud where the chain is used — `:schema` / `:validate` calls and the publish gate. ## Ref surface (`AssetRef<dataType>`) - `ref:schema()` — the merged field map (own fields + every field inherited through `extends`). - `ref:validate(values)` — `(ok, violations)` against the merged schema. `violations` is an array of `{ path, message }`. - `ref:defaults()` — the default value table the merged schema declares (a fresh, mutable table). - `ref:parent()` — the parent contract ref (`extends`), or nil for a root contract. - `ref:chain()` — the full extends chain as refs, root parent first, this contract last. - `ref:instances()` — every `.data` instance bound to this contract or to a contract that extends it, as `AssetRef`s. A full scan over the world's data assets — a discovery surface for authoring and tooling, not a per-frame call. ## Discovery - `asset.list("dataType")` — every registered contract, as `AssetRef`s. - `asset.inspect("<name>")` — the contract's files, declared schema body, instance README, and this type README. - `ls /zero/source/<Name>.dataType` lists the files the folder holds. ## Authoring conventions - Name contracts for the concept they type (`weapon`, `questObjective`, `lootTable`), not for a specific instance. - Factor genuinely shared fields into a parent contract via `extends`; don't duplicate a field declaration across sibling contracts. - Document every field's meaning and units in `README.md` — the schema only carries types and constraints, not intent. ## Common pitfalls - **Redeclaring an inherited field.** `extends` merges parent fields in; a child that re-declares a field name the parent already declared is a merge error, not a silent override. - **Cyclic `extends`.** Contract A extending B extending A raises loudly the first time the chain is resolved — fix the chain, there is no partial result to fall back to. - **assetRef/dataRef without existence checks.** `assetType` and `contract` on ref fields are declaration-time requirements; the referenced asset or data instance is checked at validation time, not declaration time. ## Related types - `.data` — a configured value instance bound to a dataType contract. - `.preset` — a named set of values for one declarer's settings schema (an assetType, an importer, a component), not a contract of its own. - `.component` — executable entity behavior, versus this type's typed configuration data. ## In the Inspector Contract: the contract it extends (a link), every field across the extends chain with its type, whether it is required, its default and its bounds or allowed values, and **Count instances**, which scans every data asset for the ones that satisfy it (a count taken before a data asset was made or removed says so).

# oceans A sea and the ground under it, as one package: the wave simulation, the surface that renders it, the seabed it is seen through, and the answer to "how high is the water here" that gameplay needs to float things on it. ```lua local Ocean = require("@builtin::systems.oceans.modules.ocean") Ocean.create({ preset = "gale" }) ``` That is a whole ocean — waves out to the horizon, foam on the breaking crests, a seabed below, and a surface that follows whoever is looking at it. To float something on it: ```lua local ocean = Ocean.forEntity(oceanEntityId) boat.position = { x, ocean:sampleHeight(x, z), z } ``` It is a building block. The sun the water glitters under, the ambient its foam sits in and the sky it reflects all come from the scene, through the same directional light and reflection probes every other material in the engine reads — so an ocean drops into a world that already has lighting instead of bringing a second set, and changing the scene's light changes the water with it. ## What it does The simulation is **spectral**: instead of animating individual waves, it builds the sea's energy across every wavelength and direction from an oceanographic spectrum, then inverse-transforms that into a height field. A real sea is what comes out — wind speed alone decides wave height, and it rises with wind the way a fully developed sea does, following the Pierson–Moskowitz law. It runs in **cascades** — independent wave fields over different patch sizes, each band-limited to its own range of wavelengths. A tile of roughly two kilometres carries the long waves and one of a few hundred metres the short ones; they sum into a surface with detail at every scale, and because the bands are disjoint no wavelength is synthesised twice. Above them a **Gerstner bank** adds the swell analytically, which no cascade can hold: a wave longer than its own patch has nowhere to live, and swell arrives from a distant storm on its own heading anyway. **Foam** is not painted on. It comes from the Jacobian of the wave displacement: where the surface folds over itself, the wave is breaking. Whitecaps appear where and when the geometry actually breaks, accumulate into a persistent world-space field, and streak behind the crest as they decay. **Colour and transparency are the same mechanism.** Per-channel Beer–Lambert extinction over the distance light travelled through water gives both — red dies within a metre, blue survives tens. That is why shallow water over sand reads turquoise and the open sea reads near-black blue without switching materials. **The seabed** is one noise field read twice: scaled it is the terrain's relief, unscaled it picks between sand and rock, so outcrops stand on the high ground and sand fills the hollows. The sun's caustic web moves over both, bent by the horizontal displacement of the water directly above it. Bodies land on it: the pass that raises the ground writes the same field out as a height patch that travels with the viewer, so what a body stands on is what the frame drew. Nothing here ships an image. Every map the surface and the seabed sample — the foam patterns, the sand, the rock, the caustics — is grown on the GPU at startup. ## The pieces | Asset | What it is | |---|---| | `components/Ocean` | Puts a sea on an entity. Its fields are the sea state; the simulation is rebuilt from them, so an ocean survives a scene reload. | | `modules/ocean` | The substrate: `attach`, `create`, `forEntity`, `sampleHeight`, `sampleDisplacement`. | | `components/Buoyancy` | Floats a rigid body on the sea. Its fields are the hull: how dense it is, how steady, and what box displaces water. | | `modules/buoyancy` | The forces: `attach`, `forEntity`, `columns`, `submergedFraction`, `restingY`. | | `modules/oceanPresets` | Nine named sea states, from `calmClear` through `gale`. | | `modules/oceanQuality` | The four tiers — how finely a sea is resolved, as distinct from what sea it is. | | `modules/oceanClipmap` | The camera-following ring geometry both the surface and the seabed are built on. | | `modules/oceanFloor` | The seabed: terrain, ground materials, caustics and the ground physics collides with. | | `modules/oceanScene` | The seam between the scene capture and the materials that sample it. | | `shaders/oceanSurface` | The water: cascade normals, absorption, exact dielectric Fresnel, subsurface scattering, sun glitter, foam, and the view from below. | | `shaders/oceanFloor` | The seabed: sand and rock blended by terrain noise, under a caustic web. | | `materials/oceanWater`, `materials/oceanSeabed` | The default looks. | | `renderFeatures/oceanScene` | Copies the frame's colour and depth so the surface can refract what is behind it and measure its own water column. | | `computeShaders/ocean_*` | The ten-stage GPU pipeline. | ## Wind is the control Significant wave height goes as the **square** of wind speed, so that one field does most of the work: | Wind | Sea | Wave height | |---|---|---| | 3 m/s | glassy, a mirror | ~0.2 m | | 11 m/s | working sea, occasional whitecap | ~2.5 m | | 24 m/s | gale, breaking and streaked | ~12 m | Everything else shapes character rather than size: `choppiness` pinches crests into peaks, `standingWaveRatio` runs waves both ways instead of only downwind, `jonswapGamma` sharpens a fetch-limited sea, and the foam layers decide how readily a breaking crest whitens and how long it streaks. Read `documentation/oceans.guide` for the full walkthrough, including the seabed, buoyancy, reflections and what each tier costs.

# assetType.shared.settings Resolves four questions about an asset's typed settings, all answered from its type's `type.yaml` — nothing here is found by convention. ```lua local Settings = require("@builtin::assetTypes.assetType.shared.settings") -- or, from inside the assetType runtime: local Settings = require("@builtin::assetTypes.assetType.shared").settings ``` ## Where does a type's schema live? `type.yaml` names it in a `settings:` block: ```yaml settings: values: "settings.yaml" # where an instance's own values live schema: { type: "settings.luau" } # one schema for every asset of this type ``` or, for a type whose settings differ per instance (an importer): ```yaml settings: values: "settings.yaml" schema: { instance: "settings.luau" } ``` or, for a type whose schema is a table its instance's own source declares and whose values live elsewhere (a component: its `public` fields, valued on each entity it is on): ```yaml settings: schema: { instance: "init.luau", export: "public" } ``` Whether an instance may lack its schema file is what the type's `files:` block says of that file. Listed under `files.optional`, it may be absent, and an instance without it declares no settings — the importer type lists it there, since most importers take none. Listed under `files.required`, or not listed at all, it must load, and an instance missing it is a broken declaration and is logged. `schema.type` is required at the folder relative to the TYPE's own `.assetType/` directory (one schema shared by every instance). `schema.instance` is required relative to each INSTANCE's own folder (`init` resolves the instance's own identity; anything else is a sibling module under it). Without `schema.export`, the file is required as a module and its return value IS the schema. With `schema.export`, the file is run in an environment of its own and `export` is read from a returned table carrying it, or else from the globals the file assigned — a component's `public` is such a global. That environment reads through to `_G` and takes every write itself; its own `_G` is itself, its `declare` and `computed` record into it, and its `task` records spawned, deferred and delayed work instead of starting it. Every other global is the real one, so a call the file makes through one runs as it does anywhere. The schema is the declared table's Field descriptors. A schema that resolves to nothing says why through `Settings.schemaProblemOf(ref)`: the file could not be read, compiled or run, or declared no such table. An instance schema is read again when its file, its type's `type.yaml`, or the entry file of any module the asset `require`s changes. `Settings.blockFor(typeName)` returns the raw block; `Settings.schemaForType(typeName)` and `Settings.schemaOfInstance(ref)` resolve the two schema shapes respectively; `Settings.schemaFor(ref)` tries the type-level schema first, falling back to the instance-level one. `ref` naming an assetType asset itself — e.g. `asset.resolve("texture", "assetType")`, rather than an instance of it — reports that type's own declared schema, the same one every instance of it reports. ## Where do an asset's values live? `settings.values` names a file living beside the asset's own content — `Settings.valuesPathOf(ref)` joins it onto the asset's path. `Settings.valuesOf(ref)` / `Settings.writeValues(ref, values)` read and write it; this module only names where it is. A type that declares its schema with no `settings.values` keeps no values in the asset — a component's live on each entity it is on — so `valuesOf` answers nil for it, `asset.create` refuses a `settings` table for it, and `asset.setSettings` refuses a write. `Settings.recordedWrite(path, text)` writes a file the way every values file is written, and an editor uses it for any other file it writes. It writes the whole contents, records the write into the open undo operation when one is open (so undoing it restores what the file held), and raises when the write does not land. ## In what order are a schema's fields declared? Every `Field.*` constructor stamps its descriptor with `declaredOrder`, one more than the last. Luau evaluates a table constructor's entries in the order they are written, so `Settings.orderedNames(schema)` lists a schema's fields — and a struct's subfields — in the order the source writes them. A values file, or a legacy `.metadata` settings block, may hold an older spelling — a renamed field, an older enum member. Every read passes what is stored through the type's `normalizeSettings` (`Settings.normalizeFor`), so it answers in the fields the schema declares today, and writes nothing. The next local edit of that asset rewrites the file in the declared spelling (`Settings.healLegacyIfNeeded`). `asset.setSettings(ref, patch)` writes a partial patch: `Settings.resolvePatch(ref, patch)` normalises it, merges it over the current values and applies the type's derived defaults for the fields it changed, and `Settings.writeValues(ref, values, patch)` applies the corrections, checks the schema and writes the file. ## How is a new asset's settings resolved at creation? `asset.create` calls `Settings.resolveForCreate(typeName, name, destPath, creationOpts, callerSettings, importerSettings)` before running the type's `onCreate`, checks the result against the schema, writes it to the values file, and hands `onCreate` a COPY of it as `opts.settings` (`Settings. cloneValues`) — never the same table the values file gets, so nothing `onCreate` does to its own copy can reach what was stamped. `onCreate` reads settings from `opts.settings` and never writes to it. `asset.create` also seeds the change baseline with the stamped values (`Settings.seedChangeBaseline`), so the values file's own first dispatch reports nothing changed and the payload `onCreate` encoded is the only encode a create runs. The layers, lowest priority first, each overriding the ones before it field by field: 1. The schema's own declared defaults (`Settings.defaultsOf`). 2. The type's own `settingsDefaults(name, opts, asked)` hook, when its `behavior.luau` exports one. `asked` holds what layers 3 to 5 name, so a default can follow a field one of them sets. 3. The Preset Manager's matching row (`Settings.presetLayerFor`). 4. The creating importer's settings for this type. 5. The `settings` table the caller passed to `asset.create`. 6. The type's own `settingsDerivedDefaults(values, explicit, changed)` hook, when its `behavior.luau` exports one — a field whose default follows another field, set only when no layer from 2 to 5 named it. 7. The type's own `settingsCorrections(values, name, opts)` hook, when its `behavior.luau` exports one — applied last, once every other layer has merged. Layers 2 to 5 are each read through the type's `normalizeSettings`, so a layer naming a field in an older spelling sets the field it names today. `asset.create`'s top-level settings alias accepts those older names too (`Settings.acceptedFieldNames`). Layer 7 is `Settings.applyCorrections(typeName, values, explicit, context)`, the one corrections path every settings write takes — this create chain, and `Settings.writeValues` for every later write (`asset.setSettings`, a type's first-encode seed, the legacy heal). `explicit` names the fields the writer asked for: the caller's `settings` table here, the patch for `asset.setSettings`. A correction lands SILENTLY on a field the writer did not name — nobody asked for that value, so overriding it just states a fact. A correction that contradicts a field the writer named REFUSES the write, naming the field, the value asked for, and why it cannot hold — the same as every other place this codebase refuses an explicit request it cannot satisfy (a `Field.checkSchema` violation, a BC7 alignment error) rather than silently rewriting it into something else. So `asset.setSettings(tex, { compression = "rgba16" })` on a mipped texture stores `generateMipmaps = false` beside it, while `asset.setSettings(tex, { compression = "rgba16", generateMipmaps = true })` is refused. `Field.checkSchema` runs once, over the result AFTER the corrections hook has applied — a bad value nothing corrects refuses the creation. ### Four hooks, four different jobs Every hook is an optional export on a type's `behavior.luau`, alongside `onCreate` / `onChange`. **None is ever handed a table to mutate** — each reads what it's given and RETURNS a table of what it wants changed (or nil); `resolveForCreate`, `resolvePatch`, `applyDerivedDefaults` and `applyCorrections` are the only places that write to the values, by merging what a hook returns the same way every other layer merges. - **`normalizeSettings(values) -> values`** maps every older spelling a stored file or a write may carry to the field and member the schema declares now, returning a new table; a table naming both an older field and its replacement keeps the replacement. The companion export **`normalizedSettingNames = { ... }`** lists the older field names it accepts beyond the schema, so a write naming one is not refused as an undeclared field. `texture.assetType`'s maps the fields its earlier schema stored to `colorSpace` + `compression`, and the older `filter` keywords to `linear` / `nearest`. - **`settingsDerivedDefaults(values, explicit, changed) -> partial?`** answers the values of fields whose default follows another field. At creation `changed` holds every field; on a write it holds the fields the write moved. A returned field applies only where `explicit` — the fields the writer named — does not name it. - **`settingsDefaults(name, opts, asked) -> partial?`** supplies a DEFAULT the schema itself has no syntax for — something only knowable at creation time, like a naming convention, a fact read off a payload the caller handed in, or a value that follows a field a higher layer sets (`asked` holds what the Preset Manager, the importer and the caller name, the higher one's value where two name a field). It runs early (layer 2 above), so any later layer — Preset Manager, importer, caller — freely overrides it. `texture.assetType`'s returns the `textureType` the name suggests (a `_normal`-suffixed name is a `normalMap`), `compression = "uastc"` and `maxDimension = 4096`, with `rgba8` for a `textureType` of `sprite` that a higher layer names; for a pre-encoded ZTEX payload it returns the colour space, compression and sampler the payload's own header carries. Either way, an explicit `settings = { ... }` from the caller still wins. - **`settingsCorrections(values, name, opts) -> (partial?, reasons?)`** enforces a CROSS-FIELD CONSTRAINT the schema itself has no syntax for — a fact about one field that depends on another field's resolved value, true regardless of which layer produced that value. It runs last (layer 7 above), over the fully merged `values`, and again on every later write of the values file. Nothing is left unmet in what gets validated and stamped — but a value the caller explicitly asked for is never silently rewritten to satisfy it; `applyCorrections` refuses instead (see above). The optional second return, `{ [field]: reason }`, supplies the "why" for that refusal message; a field with no reason falls back to a generic one. `texture.assetType`'s returns `{ generateMipmaps = false, maxDimension = 8192, colorSpace = "linear" }` whenever the RESOLVED `compression` is high-precision (the encoder stores one verbatim, linear, and refuses a mip chain or a downsample for it outright), paired with a reason naming the compression, and `nil` otherwise. ## What does a declarer declare? `Field.settingsOf(identity, mode)` embeds another declarer's schema as a struct field without restating it. The identity names one of two kinds of declarer, and `Settings.schemaOfDeclarer(identity)` tells them apart by what `identity` resolves to: - **An assetType** (e.g. `"@builtin::assetTypes.texture"`) — embeds the schema every instance of that type carries, resolved via `schemaForType`. This is the type-level shared schema from the section above, not a per-instance one — an assetType has no settings of its own to declare per instance. - **Anything else** (an importer, or any other asset that declares settings of its own) — embeds that asset's own schema, resolved via `schemaOfInstance`. Every schema this module serves has already run its `Field.settingsOf` fields through this resolution — a caller reading `schema.someField.fields` never sees an unresolved `declarer` with no `fields`. Resolution descends into an already-literal struct's `fields` and a list's `element` the same way, so a declarer embedded several fields deep is still reached. A declarer that embeds itself, directly or through another declarer, stops one level short of the loop instead of recursing forever. ## What are the defaults? `Settings.defaultsOf(schema)` reads every field's declared `default` into a plain table — a field declared without one is absent from the result rather than holding a `nil` value.

# yaml.module YAML decode + encode for authored engine content. Pure Luau, no engine dependencies — a general parsing library, not data-system plumbing. ```luau local Yaml = require("@builtin::modules.yaml") local doc = Yaml.decode(vfs.read(path)) vfs.write(path, Yaml.encode(doc)) ``` ## Supported subset - Block mappings (`key: value`) and block sequences (`- item`), nested to any depth. - Compact sequence-of-mapping entries (`- path: x` / ` kind: y`). - Flow collections — `{ a: 1, b: 2 }` and `[1, 2, 3]` — single line. - Plain scalars with type inference: `~` / `null` → nil, `true` / `false` → boolean, numeric literals → number, everything else → string. - Single- and double-quoted strings (`''` escapes a literal quote inside a single-quoted string; `\n` `\t` `\r` `\\` `\"` inside a double-quoted one). A quote opens a quoted scalar where a scalar begins — after `key:`, after a `- ` entry marker, or inside a flow collection — so a plain scalar carries an apostrophe as data (`note: the world's rules`). Quoted keys are read in flow mappings. - `#` comments — honored outside quotes, so a `#` inside a quoted string is kept as data. - Literal (`|`) and folded (`>`) block scalars — the bare indicators only. A block scalar's content is literal text: quotes (balanced or not), `#`, `key: value` and `---` inside it are data. - An optional leading `---` document marker. ## Loud-error contract Constructs outside the subset above raise instead of misparsing: anchors/aliases (`&`, `*`), tags (`!`), directives (`%`), multi-document streams (a second `---`), block-scalar chomping/indentation indicators (`|-`, `|+`, `>-`, `|2`, ...), tab indentation, and inconsistent indentation (both block structure and block-scalar bodies). Every error carries the offending line number (`yaml: line N: ...`), so a bad config points straight at the line to fix. Tab indentation is rejected everywhere — including block-scalar body lines whose leading whitespace contains a tab. A tab after the first non-space character of a line is content and passes through. ## API - `Yaml.decode(text: string): any` — decode a YAML document into a Luau value (table, scalar, or nil for an empty document). Raises on malformed input or an unsupported construct. - `Yaml.decodeWithComments(text: string): (any, boolean)` — decode as `decode` does, and report whether the text carries a comment by the decoder's own rule: a `#` at a line's start or after whitespace, outside a quoted scalar and outside a block scalar. Re-encoding the value drops such comments, so an editor that writes a document back reads this first. - `Yaml.encode(value: table): string` — encode a Luau table as YAML (block style, two-space indent, alphabetically sorted keys). Raises on values YAML can't represent (functions, userdata, non-string mapping keys). A top-level empty table encodes to an empty document, which decodes back to `nil` (the YAML empty-document ambiguity).

# content_version Per-path content-version counters — a cheap, synchronous "has this file changed?" token. An assetType behavior memoizes its parse in the ref's `runtime` keyed by the counter `get(path)` returned when it parsed, then serves every later read as an integer compare instead of re-reading and re-parsing the file. ## Why it exists A `.data()` behavior that re-reads and re-parses its source on every call is pure overhead when the file hasn't changed. This module gives it a version token to gate the rebuild on: - `get(path)` when the parse ran, stored alongside the parsed value. - On every later call, compare `get(path)` to the stored value — equal means the cache is still valid (no `vfs.read`, no parse); a bump means rebuild. ## Exports - `M.get(path: string) -> number` — the path's current version counter (`0` if never written this VM). - `M.bump(path: string)` — bump `path`'s counter, invalidating every reader memoized against its previous value. Content code rarely calls this directly. ## What bumps a counter Two write surfaces feed it, so the token reflects a change no matter where it originated: - `vfs.write` / `vfs.move` / `vfs.remove` bump **synchronously**, in the same call — so a script that writes a file and reads it back in the same tick sees the new content immediately (the asset-change `onChange` dispatch fires a frame later, too late for a same-tick read). - the generic asset-change dispatcher bumps on every source write it routes, including peer-synced and engine-originated writes that never pass through the Luau `vfs.*` surface — with the engine's normalized path, the canonical form a reader keys on. ## Per-path, not a global epoch Counters are per **path**, not one global epoch. The per-frame dirty-entity writer churns scene-dirty paths every frame during play; a global epoch would let that churn invalidate every unrelated cache. Per-path isolation means only a change to the file a reader depends on rebuilds it. The counters are held once for the process (`__contentVersion`), so a single store is shared across every VM and every copy of this module that a require-cache reset (`vfs.reload`) might create. A bumper and a reader that landed on different VMs or module copies read the same number: a write made in a worker VM, the engine thread's dispatch of it, and a write made on the engine thread advance one counter.

# data_schema Pure schema engine for the typed-data system. A contract's `schema.yaml` declares fields + constraints; this module parses the decoded declaration, merges extends chains, applies defaults, and validates value tables. Pure Luau — no FFI, no VFS reads — callers decode the YAML themselves (e.g. via `modules/yaml`) and inject asset/contract resolver callbacks. ## Exports - `DataSchema.parseSchema(raw) -> (Schema?, { string })` - `DataSchema.mergeChain(chain) -> ({ [string]: FieldSpec }?, { string })` - `DataSchema.applyDefaults(merged, values) -> { [string]: any }` - `DataSchema.validateValues(merged, values, resolvers) -> { Violation }` Types: - `FieldSpec = { type: string, required: boolean?, default: any?, min: number?, max: number?, enum: { any }?, assetType: string?, contract: string?, items: FieldSpec?, fields: { [string]: FieldSpec }? }` - `Schema = { extends: string?, fields: { [string]: FieldSpec } }` - `Violation = { path: string, message: string }` - `Resolvers = { assetExists: (identity: string, assetType: string) -> boolean, contractSatisfied: (identity: string, contract: string) -> (boolean, string?) }` ## Field types `number`, `string`, `boolean`, `vec3`, `color`, `assetRef`, `dataRef`, `array`, `struct`. - `min` / `max` apply only to `number` fields, and must be numbers. - `enum` applies only to scalar field types (`number` / `string` / `boolean`) and must be a non-empty array — the value must equal one of the listed entries. - `required` must be a boolean (YAML's bare `yes` decodes as a string and is a parse-time problem). - `assetRef` fields require an `assetType`; validation calls `resolvers.assetExists(identity, assetType)`. - `dataRef` fields require a `contract`; validation calls `resolvers.contractSatisfied(identity, contract)`. - `array` fields require an `items` spec (a nested FieldSpec every element must satisfy). - `struct` fields require a `fields` map (nested subfield specs); struct values reject unknown keys the same way top-level values do. ## Usage ```luau local DS = require("@builtin::modules.data_schema") -- 1. Parse each contract's declaration in the extends chain, root -- parent first. local itemSchema, p1 = DS.parseSchema(Yaml.decode(itemYaml)) local weaponSchema, p2 = DS.parseSchema(Yaml.decode(weaponYaml)) -- 2. Merge the chain into one field map. A child redeclaring a field -- the parent already declared is a problem. local merged, mergeProblems = DS.mergeChain({ itemSchema, weaponSchema }) -- 3. Fill in schema defaults for a value table that omits some fields. local filled = DS.applyDefaults(merged, rawValues) -- 4. Validate a value table — missing required fields, constraint -- breaches, unknown fields, and ref fields via the injected -- resolvers. local violations = DS.validateValues(merged, filled, { assetExists = function(identity, assetType) return asset.exists(identity, assetType) end, contractSatisfied = function(identity, contract) return dataInstanceSatisfies(identity, contract) end, }) ``` ## Notes - Inputs must be acyclic tables — YAML-decoded data always is. - Every parsed FieldSpec, Schema, and merged field map is frozen (`table.freeze`): cache them freely; any accidental mutation raises at the mutation site. - A schema declaration's top-level keys are `extends` and `fields` only; anything else (e.g. an `extend:` typo) is a parse problem. `$schema` is the one accepted-and-ignored tooling key. - `parseSchema` rejects a default value that violates its own field spec at declaration time (checked with `resolvers = nil`, so ref fields are only shape-checked, not resolved, against a default). - `mergeChain` order matters: pass the chain root-parent-first, derived-contract-last. Redeclaring an inherited field is a merge problem, not a silent override — shared shape comes from the parent, new shape from the child. A nil chain hole (e.g. a failed `parseSchema` result passed straight in) is a problem entry, and a non-Schema entry (`false`, a string, ...) raises at the call boundary — never a silent truncation. - `applyDefaults` never mutates its inputs; it returns a new table with deep copies of both the explicit values and any filled-in defaults. Defaults fill recursively: struct values gain their subfield defaults and array elements gain their item defaults, at every depth. - `validateValues` treats a field with a schema default as never "missing" even when `required = true` and the value table omits it — `applyDefaults` fills that gap, at every depth. ## Editing values through Field controls A data instance's values edit through the same typed controls as asset settings. - `DataSchema.toFields(merged)` gives one Field descriptor per contract field: a number with both bounds is `Field.range`, with one or none `Field.number`; a string or number with `enum` is `Field.enum` (a number enum's members as strings); boolean, vec3, color, assetRef, dataRef, array and struct map to `Field.bool`, `Field.vec3`, `Field.color`, `Field.assetRef`, `Field.dataRef`, `Field.list` and `Field.struct`. Every descriptor is `NoSync`, and a struct's fields are built in name order. - `DataSchema.toFieldValues(merged, values)` turns the values a data file holds into the forms those controls read: a colour `"#rrggbb[aa]"` into `{ r, g, b, a }`, a vec3 `[x, y, z]` into `{ x, y, z }`, a reference's identity into `{ __ref = guid }`, a number enum member into its string. Arrays and structs convert item by item. - `DataSchema.toFieldValues(merged, values, base)` resolves a reference within its field's category (`assetType` for an assetRef, `data` for a dataRef), a `~` form against `base` (the data file's path), and a guid by guid. - `DataSchema.fromFieldValues(merged, values)` is the inverse, for any subset of fields. - `DataSchema.editedValues(merged, stored, edited, base)` gives the top-level values a control edit writes: each named field as stored, with only the leaves the edit changed replaced, each in the form the file held it in. Untouched values keep their stored value and form (a colour held as numbers above 1, a map-form vector, keys the contract does not declare). In a list, each item the edit leaves alone is found by what it holds, so removing or reordering items keeps every other item as stored; an added item takes the form the list's items are stored in.

# assetType runtime The machinery that reads a `<typename>.assetType/behavior.luau` and turns its declarations into live behaviour. A `behavior.luau` is a table of declarations — `ref` methods, `modules` shared code, an `events` schema, a `namePattern`, `refShapes`, and the `onCreate` / `onRegister` / `onChange` / `onDelete` / `validate` / `settingsDefaults` / `settingsCorrections` hooks. None of it runs itself. This is the code that runs it, and it lives here because reading a type's declarations is the **assetType type's own behaviour** — the same way `material.assetType` owns what a `.material` does. ## Sub-modules | Module | Reads | Responsibility | |---|---|---| | `ref.module` | `ref`, `modules` | Builds every `AssetRef` envelope, attaches the shared metatable, and dispatches per-type methods and shared modules onto it. Also owns edit-mode write-behind persistence. | | `create.module` | `onCreate`, `namePattern`, `validate` | Backs `asset.create`: resolves the type, checks the name against its pattern, runs `onCreate` (or clones `template/`), and writes the instance. `validate.module` beside it checks a creation `opts` table against the type's `createSchema`. Before running `onCreate`, resolves the type's settings chain (below) and hands the result to the hook as `opts.settings`. | | `settings.module` | `settings`, `settingsDefaults`, `settingsCorrections` | A type's declared settings schema and where its values live (`type.yaml`'s `settings:` block). `Settings.resolveForCreate` layers the schema's own defaults, the type's own `settingsDefaults(name, opts, asked)` hook (a DEFAULT the schema can't express — a name-derived convention, a fact read off a payload the caller handed it, a value following a field `asked` shows a higher layer naming; any later layer overrides it), the Preset Manager, an importer's settings, the caller's `settings` table, then the type's own `settingsCorrections(values, name, opts)` hook (a CROSS-FIELD CONSTRAINT the schema can't express, applied last over the fully merged values). A correction over a default/preset/importer value lands silently; a correction that would override what the caller's own `settings` table explicitly asked for refuses the creation instead, naming the field and why. Neither hook is ever handed a table to mutate; each returns what it wants changed (`settingsCorrections` may also return a `{ [field]: reason }` table for that refusal message). `Settings.cloneValues` deep-copies a values table — `create.module` hands `onCreate` a copy, never the table it stamps. `Settings.valuesOf` / `writeValues` read and write an asset's own values file. | | `typeYaml.module` | `type.yaml` | The folder a type lives in and its parsed `type.yaml`, decoded once per content version of the file. `settings.module` and `inspector.module` read their blocks through it. `about` / `aboutAt` read a type's `about.yaml` (`intent`, `function`, `usage`), leaving out any key that is empty or still starts with `[[describe]]`; `aboutRows` and `aboutMarkdown` lay the texts out for the Inspector and the `types/<name>` guide. | | `inspector.module` | `type.yaml`'s `inspector:` block | Which inspector a type declares for its assets (`inspector: { type: ... }` or `{ instance: ... }`), and the declaration that file returns — the sections it adds, the generic ones it replaces, and their order — or the problem that kept it from loading. | | `onRegister.module` | `onRegister` | Fires an instance's once-only registration hook — on arrival, on world load, and for `@builtin` library instances. | | `changeDispatch.module` | `onChange`, `onDelete`, `refShapes` | Routes a VFS source write or a folder delete to the enclosing typed asset's type hooks. | | `refShapes.module` | `refShapes`, `ref` | Publishes what every `AssetRef<category>` answers to, so a member read on an asset-typed value is checked against that category's real surface. | | `events.module` | `events` | The per-asset event runtime behind `ref.events`. | | `instantiable.module` | `ref.instantiate` | The instantiation contract an asset type opts into: `root` stands the root entity, `place` applies the base placement opts to one the type adopted, and `result` shapes the `(root, idMap)` every `instantiate` returns. Also registers the `sceneInstantiable` field-constraint validator. | | `declaration.module` | `type.yaml` | The type's decoded declaration, read once and held until a write inside an `.assetType` folder; what every question about a type as a whole reads. | | `previewRecipe.module` | `type.yaml` `preview:` | How an instance's `preview.png` is produced: which of the four recipes (`instantiate`, `image`, `surface`, `custom`) the type declares, and what that recipe needs. | ## Reaching it ```luau local rt = require("@builtin::assetTypes.assetType.shared") rt.ref.loadTypeBehavior("material") ``` Fields resolve lazily. The prelude requires the sub-modules directly, in dependency order (`ref`, then `changeDispatch`, `onRegister.install()`, `refShapes.install()`) — a table that required all six on load would take that ordering away from it.

# Package (asset type) A package is an asset — a `<Name>.package/` folder that bundles components, modules, scenes, presets, tools, and any other typed sub-assets under one identity, installed into a world as one unit. Packages are how authoring sets get distributed across worlds. A **library** is the addressable root scope content resolves under (`@builtin`, `@<name>`) — a whole world mounted into this one under a namespace, via `zeromind.installLib` / `world.installLibrary`. A package is an asset that lives inside such a root, and one library holds as many packages as its author put there. A package is installed by guid the way every asset is (`zeromind.install`, `zeromind.installAsset`). ## When to use one - You're authoring a coherent feature suite (character controller stack, voxel engine, UI kit, animation library) and want to ship it as one install target. - You want a stable identity worlds can install and resolve sub-assets against (`@<lib>::pkg.sub_module`). - You want versioning + a per-package metadata layer that travels with the contents. If you're authoring inside a single world and don't need a separate install lifecycle, you don't need a package — drop your `.component` / `.module` / etc. directly in `/zero/source/`. Packages are for cross-world distribution. ## Where it lives - Source: `/zero/source/.../<Name>.package/` (or, for legacy packages, a folder containing `package.yaml` at its root). - Identity: `<Name>` (the `.package` suffix collapses in identity — mirrors `.module`). A file at `<Name>.package/<sub>/init.luau` resolves under the same identity it would at `<Name>/<sub>/init.luau`. - Folder shape (container-style — open child set): - `package.yaml` — metadata (name, version, description). **Required.** - `README.md` — instance documentation. **Required.** - `.metadata` — agent-editable tags + free-form fields. **Required.** - Sub-asset folders: any combination of `.component/`, `.module/`, `.scene/`, `.preset/`, `.tool/`, `.toolbox/`, `.material/`, `.shader/`, etc. The validator permits unlisted children (`allow_unlisted: true`) by design — packages are open containers. ## How to create one ```luau asset.create("package", "<Name>") -- Creates: /zero/source/<Name>.package/ -- package.yaml (metadata scaffold) -- README.md (instance README template) -- `folder` places it in a subfolder of /source instead of the root: asset.create("package", "<Name>", { folder = "systems" }) ``` Then scaffold sub-assets inside it: ```luau local pkg = asset.resolve("<Name>.package") asset.create("component", "Spinner", { into = pkg }) asset.create("module", "util", { into = pkg }) ``` ## How it operates 1. **Registration.** Writing `package.yaml` indexes the package with the package registry. 2. **Install.** A package is installed by guid, the way every asset is: `zeromind.install` from the shared library, or `tools.use("zeromind", "installAsset", <guid>)` inside the engine. The install writes the package's files (and the deps its `.refs` record) into this world's source, so its sub-assets resolve here. `tools.use("zeromind", "preview", <guid>)` reports what an install would write before it writes anything. 3. **Sub-asset resolution.** Because `.package` collapses in identity, sub-asset paths work whether the package folder is suffixed (`<Name>.package/<sub>`) or not (`<Name>/<sub>`). 4. **Updates.** `tools.use("zeromind", "updates")` lists installed content with upstream changes available; re-running the install pulls them. 5. **Metadata.** `package.yaml::name` overrides the folder stem if present (rare); `version` + `description` are surfaced in the package index. 6. **Hot reload.** Edits to sub-assets hot-reload as normal; edits to `package.yaml` reload package metadata. ## Discovery - `asset.list("package")` — every registered package. - `asset.inspect("<name>")` — sub-asset catalog, source, this type README. - `ls /zero/source/<Name>.package` lists the files the folder holds. - `library.list()` — the library assets registered in this world, including the ones packages under an installed library contribute. ## Authoring conventions - Name packages by their feature (`voxels`, `cameraRigs`, `dialogSystem`), not by their owner — the host library is the `@<lib>::` scope prefix. - Cluster cohesive sub-assets together. A "character controller" package should ship the controller component, its preset configs, its supporting modules, and a demo scene — not just the component. - Document the package's surface in `README.md` — what install installs, what each sub-asset does, how they relate. Agents reading `cat /zero/source/<Name>.package/README.md` get the full picture in one shot. - Version conservatively — breaking a package means breaking every world that installed it. Use semantic version bumps. ## Common pitfalls - **Missing `package.yaml`.** Without it the folder isn't recognized as a package even if it has a `.package/` suffix. - **Dependency installs.** A package that depends on another package must declare it (in `package.yaml::dependencies` once supported) and the parent world must install dependencies in order. - **Identity collapse.** Sub-asset paths skip the `.package` suffix. Don't include `.package` in `require` strings. ## Referencing inside a package: the `~` rule `~` means **this package**, resolved structurally from the referring file's own location. It is the only package-specific syntax. It is rename-safe (no package name is ever written) and library-agnostic (it never names the host library, so it survives `@builtin` being renamed or the package being mounted elsewhere). `~.tail` maps to `<pkg>.package/tail` from anywhere inside the package. | Referencing from | Use | Example | |---|---|---| | An asset/module **inside this package** | `~.tail` | `require("~.modules.myThing")`, `shader: "~.shaders.myThingBlend"` | | A **different package** under the same root | root-relative identity | `require("@root::systems.otherPkg.modules.x")` | | A **different library's** public API (a deliberate external dependency) | `@otherlib::…` | `require("@physics::modules.rigidbody")` | **Never write `@builtin::` (or any host-library name) to reference your own package** — that couples the package to the library it currently lives in and breaks if the library is renamed or the files move. Use `~.`. It works from Luau `require()` and from asset-reference strings in data files (a material's `mat.yaml` `shader:` field, a component's default asset ref); the engine resolves it against the referring file's own package. `asset.resolve` takes a `~.` name the same way, against the package of the file that calls it: `asset.resolve("~.materials.myThingStandard", "material")`. `~.` is the package-relative self-reference; `@root::` is the root-relative one (the library root, or the world source tree for non-library content). The `core/requiring-modules` guide covers the root model in full. A package that ships substantial functionality should include a `.guide` asset (a `<name>.guide/guide.md` folder anywhere under the package); the `guides` tool discovers it live, so collaborators find the system the way they find built-in guides. A package's test suite reaches the shared `Test` framework through its enclosing asset: `local Test = asset.containing(__FILE__).modules.shared` (`asset.containing` returns the deepest enclosing typed asset, the `.testSuite`, not the outer `.package`). ## Related types - Any of `.component`, `.module`, `.scene`, `.preset`, `.tool`, `.toolbox`, `.material`, `.shader`, `.style`, `.service`, `.importer` — packages bundle these. ## In the Inspector Package: the name, version and description package.yaml declares, how many things the package holds and what they are, and **Open** for package.yaml. A package.yaml that does not decode is listed under Problems with the decoder's error.