# editorPanel A dock tab in the editor, as an asset. A `<name>.editorPanel/` folder carries an `init.luau` that returns the tab's spec: ```luau local edui = require("@builtin::~edui.framework") return { title = "My Tab", -- the tab's label (`label` is accepted too) order = 60, -- sort position in the menu dock = "bottom", -- seeds the FIRST arrangement: left | right | bottom | center menu = "scene", -- which top-bar menu lists it; an unknown name creates that menu startClosed = true, -- registered closed; opened from the menu build = function() -- the tab's body, called again whenever it should change return edui.panel{ body = edui.text{ text = "hello" } } end, } ``` `build` is the only required field. The tab id defaults to the folder stem (`myTab.editorPanel` → `myTab`); an explicit `id` overrides it, and a duplicate id replaces the prior registration. An init may return a LIST of specs when one asset carries several tabs — a spec this registration no longer declares has its tab taken down. The spec is forwarded whole to `edui.shell.addPanel`, so anything the shell accepts (`badge`, `badgeColor`, …) works here; `man edui.shell` is its contract. `build` may return `nil` to mean "nothing changed, keep what is drawn" — the shell rebuilds open tabs on a timer, and a panel that re-publishes an identical tree pays for it. Only the ACTIVE tab of a dock leaf is rebuilt at all. An `init.luau` that fails to load does not break the editor: its tab comes up carrying the failure — the path and the error, selectable — so a panel that will not compile says so where you would look for it. Every instance of this type becomes a tab: the ones in the open world, and the ones the built-in library ships, on the same terms. Adding a tab to a project is creating a new `editorPanel` asset: it comes from the template above and registers its tab at once, wherever under `/source` it was made (`editorPanels/` is the type's conventional folder). Editing the `init.luau` re-registers the tab, deleting the folder removes it. Nothing registers panels by name anywhere. `guides { path = "editor/edui/edui" }` — the guide beside this type, inside the edui package — covers the build model, where panel state lives, and the `edui.*` surface a body draws with. ## In the Inspector Panels: each panel id this file registers (`panelRef:panelIds()`), whether it is open, an **Open** action for it, and **Open** for the source. A file whose init.luau does not load says why.

# edui (module) The editor UI framework, built on the CSS-parity `ui.*` surface. `edui` is **editor-only** — gameplay and normal UI author raw `ui.*` widget trees (`{ type, style, props, children }`) and need no framework. `edui` provides the one thing a framework earns its keep for: editor chrome — a reactive app, a dock shell, and chrome primitives (panels, trees, toolbars, inspector rows, context menus, drag-and-drop). It replaces the deprecated `zui` for the editor. ## The reactive core (`edui.app`) `ui.*` dispatches interaction through **string callback ids** — a widget carries `props.onClick = "<id>"`, and the screen's registered env receives `onCallback(id, data)`. Closures can't cross the FFI boundary, so raw `ui.*` makes you manage those ids by hand. An `edui` **app** hides that. During a build it allocates an id per closure and records id→closure; its single `onCallback` looks the id up, calls the closure, and rebuilds: ```lua local edui = require("@builtin::modules.edui") local count = 0 local app = edui.createApp("counter", { layer = editorMask }) app:mount(function(a) return { type = "vertical", children = { { type = "label", props = { text = "count: " .. count } }, { type = "button", props = { text = "+1", onClick = a:cb(function() count += 1 end, "inc") } }, }, } end) ``` - `app:cb(closure, key?)` — allocate a callback id for `closure`. Pass a stable `key` so the id survives rebuilds (required for focus / drag / `ui.widgetState`). - `app:dispatch(id, data)` — what the broadcast calls; routes id→closure and rebuilds. Returns whether this app owned the id. - `app:markDirty()` — request a rebuild (coalesced during an in-progress build). - `app:rebuild()` / `app:mount(fn)` / `app:unmount()` — lifecycle. - `edui.current()` — the app whose builder is running (the primitives use it so you don't thread the app through every call). Builder and handler errors are logged, never thrown — one bad build never wedges the editor.

# editorSelection Named selection scopes for the editor. A scope is an independently tracked, ordered set of typed refs plus a primary (the last ref added or clicked). Distinct scopes never clobber each other, so viewport, outliner, inspector and asset browser share one answer to "what is selected" per kind. A ref is `{ kind: string, id: string }` — a stable id, never a display string, so rename/move never invalidates a selection. ## Exports - `M.scope(name) -> Scope` — get/create a named scope handle. - `M.set(scope, refs)` — replace refs in order; primary becomes the last. - `M.get(scope) -> { Ref }` — refs in click order (fresh array). - `M.primary(scope) -> Ref?` — last-clicked ref, or nil. - `M.clear(scope)` — empty a scope. - `M.toggle(scope, ref)` — add if absent, remove if present. - `M.add(scope, refs)` — add each ref not already present; primary becomes the last added. - `M.remove(scope, refs)` — remove each of `refs`; primary becomes the last remaining or nil. - `M.contains(scope, ref) -> boolean` — membership by `(kind, id)`. - `M.count(scope) -> number` — the scope's selection size. - `M.subscribe(scope, fn) -> handle` / `M.unsubscribe(scope, handle) -> boolean`. - `M.context() -> { scope, refs, primary }` — last-focused scope, for command ctx. ## Usage ```luau local Selection = require("@builtin::modules.api.editor.selection") local scope = Selection.scope("entity") Selection.set(scope, { { kind = "entity", id = "player_1" } }) Selection.subscribe(scope, function() refreshInspector() end) ``` ## Notes - State lives in a fixed `_G` slot, seeded pre-seal by the boot chain (`prelude.luau`); it survives hot-reload and edit↔play flips. Mutations after boot write into nested tables only. - `set` / `toggle` / `clear` mark their scope as last-focused, which drives `context()` and therefore which scope commands act on. - The service holds the editor's selection state in Luau. Refs handed back by `get` / `primary` / `context` are copies, so a caller can hold or mutate them without touching internal state.

# assetBrowser <!-- zero:scaffolded-readme --> <!-- Replace the line below with what this module provides and who consumes it, then delete both comment lines. --> TODO: describe this module.

# entityOps Operate on scene entities — spawn, instantiate content, change state, swap, and navigate the hierarchy. Every tool resolves targets by entity **name or id** (single, a list, or the records `scene.find` returns) or by a **`scene.find` query** (`{ name = { "wheel" } }`, `{ component = { "Light" } }`, `{ under = { "car" } }`) that names a selection without looking it up first, and asset inputs by a name / path / identity string that the tool resolves and reports back canonically — so the caller never needs to know an asset's exact identity up front. Finding and reading entities is the `scene` toolbox (`scene.find`, `scene.tree`, `scene.summary`); this toolbox is the operating surface. ## Spawn + instantiate - **spawn** — spawn entities from a template: name the components they carry and their field values, plus a transform. Authored (serializing) components only. Pass a `{ defaults, items }` list to spawn MANY in one call with shared defaults and per-item overrides — a six-walled room is one call, not six — validated whole before any entity is created. - **fromAsset** — instantiate an existing asset (bundle / avatar / mesh / material / texture, or anything with an `:instantiate()`): resolves a name/path/identity string, dispatches by category, and reports the canonical asset it hit. Controls the live `link` and `synced` flags. ## State + hierarchy - **modify** — delete / enable / disable / hide / show / temporary / reparent / rename, over one or many entities. - **swap** — replace an entity with another entity that already exists in the scene (moves it into the target's slot). - **addComponents** — attach component(s) with setup data to one or many entities; `create` spawns missing ones. - **removeComponents** — detach component(s) from one or many entities, reporting per entity what was `removed` and what was `absent`. - **component** — inspect a component TYPE's schema: its public fields (name + type + current value), methods, and lifecycle hooks — so you set fields that exist instead of guessing. Reach for it before `addComponents` / `spawn`. - **roots** — find the root ancestor of one or many entities. ## Transform + copy - **transform** — move, rotate and scale: absolute sets, relative offset / rotate / scaleBy, and grid snapping. With no ops it is a pure read of the current transform. - **duplicate** — copy entities, one at a time or as a numbered run stepped along an accumulating `offset`. ## Addressing a set you built Every tool here resolves targets by **query** as well as by name or id, so a set can be operated on without retaining a single id. Tag the set as you build it, then address it by that tag: ```lua -- Build the set in one call, tagged. entityOps.spawn({ defaults = { components = { Model = { model = "cube" } }, attributes = { group = "roomA" } }, items = { { name = "wall_n", position = { 0, 1, -2 } }, { name = "wall_s", position = { 0, 1, 2 } } }, }) local set = { attribute = { name = "group", value = "roomA" } } entityOps.transform(set, { offset = { 0, 5, 0 } }) -- move the whole set renderLayer.set(set, "shell") -- re-layer the whole set entityOps.modify(set, { delete = true }) -- remove the whole set ``` The tag is an ordinary entity attribute, so it persists with the scene and is as much a part of the content as a name is. To see what is already present rather than what you made, `scene.find` with no search axis returns the whole live population, and `include = { "transform", "componentValues", "attributes" }` annotates each hit — one call, no follow-up per entity.

# 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.

# edui The editor UI framework, on the CSS-parity `ui.*` surface. An editor-only toolkit: panels author closures instead of callback ids, a dock shell over `ui.*` native docking, and typed editor-chrome primitives. Gameplay and normal world UI author raw `ui.*` trees and need none of this. **`edui.guide` beside this file is how to use it** — creating a panel, the spec it returns, how a panel is drawn and redrawn, the whole widget vocabulary, and how a panel reaches the selection and the dock. ## What installs - **`framework`** — everything under one table. From outside the package, `require("@builtin::~edui.framework")`; inside it, `require("~.framework")`. It carries `app`, `widgets`, `shell`, `topbar`, `query`, `fileDialog`, `worldDialog`, `stats`, and the chrome primitives flat (`panel`, `tree`, `field`, `section`, `text`, `button`, `menu`, …). - **`app`** — maps a panel's closures to `ui.*` callback ids, dispatches to them, and coalesces redraws. - **`widgets`** — the primitives, plus the typed inspector layer (`widgets.tree`, `widgets.fields`, `widgets.controls`). - **`inspector`** — the Inspector as an ordered list of sections: the generic asset sections, the Settings section and its actions, and the merge with the sections a type's `inspector.luau` declares (`inspector.assetSections`, `inspector.settingsSection`), and the building blocks those sections compose (`inspector.parts`, reached as `ctx.parts`). - **`shell`** — the dock: one `ui.*` `dockArea` holding a `dockPanel` per registered panel, and the panel registry behind it. ## Referencing - Inside this package, modules reference siblings with `~.` — e.g. `require("~.app")`, `require("~.widgets.fields")`. - Editor content built on the framework references it by package identity — `require("~edui.framework")`, `require("~edui.shell")`.

# Module (asset type) A module is a reusable, stateless (or globally-stateful) Luau library that other code pulls in with `require()`. Modules are the unit of factored-out logic in a world: helpers, math libraries, format parsers, registries, shared algorithms. ## When to use one - You have logic you want to share across multiple components, services, scenes, or tools. - You have a registry, lookup table, or shared cache that callers all read from / write to. - You want a stable API surface (`M.fn`) other code can depend on. If the logic is bound to one entity, use a `.component`. If you want a named UI of fields rather than functions, use a `.preset`. ## Where it lives - Source: `/zero/source/.../<name>.module/` - Identity: the source path with `/` written as `.` and each segment's type suffix dropped — `/zero/source/demo/beats.module` is `demo.beats`, and `/zero/source/kit.package/beats.module` is `kit.beats`, the container's name kept and its `.package` suffix gone. `asset.create` returns this string, `asset.resolve(...).identity` reads it back, and the `require` forms below write it as `<identity>`. - Folder shape: - `init.luau` (or `init.lua`) — module body. **Required.** Returns a table (conventionally named `M`). - `README.md` — instance-level documentation. **Required.** - `.metadata` — agent-editable tags + free-form fields. **Required.** ## How to create one ```luau asset.create("module", "<name>") -- Creates: /zero/source/<name>.module/ -- init.luau (canonical `local M = {} … return M`) -- README.md (instance README template) -- `folder` places it in a subfolder of /source, and that subfolder -- leads the identity: `{ folder = "lib" }` produces `lib.<name>`. -- `into` authors it inside a resolved container (a package, a toolbox), -- whose own identity leads the same way: asset.create("module", "<name>", { folder = "lib" }) asset.create("module", "<name>", { into = asset.resolve("myPkg.package") }) ``` ## How it operates 1. **Registration.** Writing `init.luau` into a `.module/` folder indexes the asset and registers the module path with the resolver. 2. **Loading.** The first `require("<identity>")` runs the file's body and caches the returned table. Subsequent requires from anywhere return the **same table** — this is the shared-state lever for "module-local" registries. 3. **Hot reload.** Editing the file re-runs the module body and folds what it returns into the table already loaded, so that table keeps its identity: a caller that captured it with `require` reads the new source's functions and values through the reference it already holds, and a later `require` returns that same table. A key the new source drops goes away; a key something set at runtime stays. The body's own `local`s start again from their initial values, so state that must outlive an edit lives in `modules.state()` (`guides { path: "core/scripting-and-tasks" }`). 4. **Identity resolution.** A module is reached by its `<identity>`, and where the caller lives decides which spelling of it resolves. For a module in a **world**, from a caller in that same world — another module, a component, a scene entrypoint, or an `execute` chunk: - `require("<identity>")` — the identity on its own, resolved against the caller's own root. It carries every folder segment, so a module created with `{ folder = "demo" }` is `require("demo.beats")`. - `require("@root::<identity>")` — the same root-relative resolution, written out. - `require(".sibling")` — a module in the same folder, by its bare name; `..name` steps up one folder, `...name` two. Logs, stack traces and hot-reload notices name that same module `@local.source.<identity>` — its key under the world source root. The `<identity>` tail of that key is the form above, so a trace reading `@local.source.demo.beats` is `require("demo.beats")`. For a module in a **library** — content under `/zero/source/libs/@<lib>/` — `@<lib>::` addresses that library's root from anywhere: `require("@builtin::modules.transform")`. Mounting a world as a library moves its files under such a root and flips the caller root to `@<lib>::`, which is what keeps the root-relative forms above resolving across the move. ## Discovery - `asset.list("module")` — every registered module. - `asset.inspect("<name>")` — public functions, source path, this type README. - `ls /zero/source/<name>.module` lists the files the folder holds. ## Authoring conventions - Return a single `M` table from `init.luau`. Top-level statements with side effects run on first require — useful for one-time initialization, dangerous if they touch the engine before it's ready. - Write exported functions as `typed function`, not `function`: the argument types are enforced at the call and the checker knows the signature, so a caller's mistake is reported where they made it. - Annotate exported functions with `--!desc` / `--!arg` / `--!return` / `--!example` so the LSP, `tools.list`, and `asset.inspect` surface them. A function with no `--!desc` is reachable only by someone already reading this file. - Declare a VALUE with `Field.<kind>(default, mode, description)`, and a table whose members are reached through a metatable with `--!members <TypeName>` — the latter gives the surface its accepted member set, its type, and its documentation from one table. See `guides { path: "core/authoring" }` for all four rules and `modules/api/engine/entity.module/members.module` for a worked member table. - Keep module state in module-local upvalues or in `modules.state()`. Globals leak across reloads. Module-locals start again from their initial values with each hot reload; the table `modules.state()` returns is the same table on both sides of every reload. - Prefer focused modules over kitchen-sink modules. If two halves of a module have no shared state, split them. ## Common pitfalls - **Cyclic requires.** A `require` chain that loops will return the partial table (the half built before the cycle was detected). Design for one-way dependencies. - **Engine-time side effects.** Don't `entity.spawn` at module top-level — the engine may not be ready. Expose an `M.init` and call it from a scene entrypoint. - **Hot-reload + module-local cache.** A module that caches expensive computation in upvalues loses that cache on reload — fine for dev, but be aware in performance work. - **`init.lua` vs `init.luau`.** Either works, `.luau` is canonical. - **Writing one while play runs.** A `/source` write made while play is running lands on the play shadow, and a guarded play-exit discards it unless it is kept. One `.module` write shadows `init.luau`, the `README.md` and the `.metadata` together. `vfs.write(path, bytes, { durable = true })` skips the shadow, and `vfs.promotePlayShadow` keeps what is already on it — the `core/vfs` guide has the model and what each route costs. ## Related types - `.component` — for entity-bound state + lifecycle hooks. - `.service` — generates content you don't have yet (a mesh, sound, texture, …) via a metered provider. - `.tool` — for a single agent-callable function with a YAML schema. - `.package` — to group several modules + components + scenes into one shippable folder. ## In the Inspector Exports: what the module exports (name, kind, signature), parsed from its source without running it, with **Check** (the LSP's diagnostics for its entry file) and **Open**.

# edui.widgets (module) Editor-chrome primitive builders for `edui`. Each returns a styled `ui.*` widget subtree; the common ones are re-exported flat onto `edui` (`edui.panel{...}`, `edui.text{...}`, `edui.iconButton{...}`, …). Two things make these "framework" primitives rather than raw `ui.*`: 1. **They read the active theme's editor tokens** (`editor-row-height`, `editor-selection-bg`, `editor-hover-bg`, `border`, `radius-md`, …) via `ui.getToken`, so chrome looks like the editor by default and restyles with the theme. `edui.palette()` returns the resolved set. 2. **Interactive builders register their closures with the currently-building `edui` app** (`edui.current()`), so you pass `onClick = function() end` and never touch a callback id. ## Builders - Containers: `vbox`, `hbox`, `spacer`, `divider`, `panel`, `toolbar`. - Content: `text`, `svgIcon`, `iconButton`, `button`. - `panel{ title? | toolbar?, body }` is the standard dockable-panel shell (a header over a height-filling body). - `nodeGraph{ key, nodes, edges, selected?, height?, onSelect?, onMove?, onConnect?, onDisconnect?, onDelete?, onOpen?, onField?, redraw? }` — a node graph on one canvas: titled nodes with output and input ports, wires between them, and a value on every input port that has no wire into it. Drag the background to pan, scroll to zoom, drag a node to move it, drag from a port to another port to connect, drag a connected input away to pick its wire up, click a value to edit it where it stands, press Delete to remove the selection. The widget draws and reports; the owner holds the graph and applies what `onField`, `onConnect`, `onDisconnect`, `onMove` and `onDelete` report. Nodes with no position are laid out left to right over the wires. `edui.nodeGraphView(key)` answers where the view stands and, through its `locate`, where a port or a value is on the canvas. - `iconButton{ d, tooltip?, active?, onClick, key }` — a hoverable/active icon square; `d` is an SVG path (or full `<svg>`). Icons are inline SVG (feather/lucide-style 24-view stroke paths), matching the editor's icon language — pass a path `d` and it is wrapped for you.

# entityOps.addComponents Attach component(s) — with their setup data — to one or many entities in a single call, creating the entities first when asked. ```lua entityOps.addComponents("crate", { Physics = { kind = "dynamic" } }) entityOps.addComponents({ "crate_1", "crate_2" }, { "Physics", "Audio" }) entityOps.addComponents("spinner", { Rotator = { speed = 2 } }, { create = true }) ``` Targets are entity **names or ids** (arrays and `scene.find` results pipe straight in). Components are a name, an array of names, or a `{ Name = dataTable }` map carrying each component's setup data — names accept the leaf (`"Physics"`), the full identity (`"@builtin::components.Physics"`), or a VFS path, resolved before anything mutates. `create = true` spawns a fresh root entity for any string target that matches nothing, so one call both creates the entity and gives it its setup. Returns one `{ id, name, added, created? }` record per entity.

# entityOps.component Inspect a component **type** so you set fields that exist instead of guessing. Reports the component's public fields (name + type + current value), its callable methods, its lifecycle hooks, and its asset-ref fields. ```lua entityOps.component("Camera") -- fields, methods, hooks + default values entityOps.component("Model", { on = "my_prop" }) -- actual values on that entity entityOps.component("@builtin::components.Light") ``` Resolves the component by name / identity / VFS path. Pass `on` (an entity name or id that carries the component) and every field's `value` is that entity's **actual** value, read off its live component proxy; omit `on` and each `value` is the **declared default**, as written in the component's source. A live value keeps its shape: a number reads back as a number, a vector or struct as its plain table. A field that resolves on read reports the identity of what it points at — an asset (`resource` / `assetRef`) as a `{ __ref, identity, name, type }` envelope whose `identity` you hand straight back to `addComponents`, an `entityRef` as the entity id. A field whose live value could not be read carries an `error` instead of a value, so a value that failed to read is never mistaken for the default. ```lua -- on a wall carrying a mesh and a custom material entityOps.component("Model", { on = "wall_north" }) -- fields: model = { __ref = "336f4feb-…", identity = "@builtin::meshes.cube", name = "cube", type = "mesh" } -- material = { __ref = "99d699e9-…", identity = "@user::materials.brick", name = "brick", type = "material" } ``` Returns `{ identity, description, builtin, executionOrder, hooks, fields, methods, assetFields, source }`. Reach for it before `entityOps.addComponents` / `entityOps.spawn` to learn the exact field names and value shapes — the fix for setting fields a component doesn't have. To inspect the components + values on an *entity* (rather than a component type's schema), use `debug.inspect`.

# entityOps.duplicate Copy entities that already exist — one duplicate, or a numbered run of them spread along an axis. ```lua entityOps.duplicate("crate") entityOps.duplicate("crate", { count = 5, offset = { 2, 0, 0 } }) entityOps.duplicate("pillar", { count = 4, offset = { 0, 3, 0 }, name = "pillar_%d" }) entityOps.duplicate({ name = { "tree" } }, { offset = { 10, 0, 0 } }) ``` Targets take a name or id, a list of them, `scene.find` records, or a **query** resolved for you — so everything matching `{ name = { "tree" } }` is copied without looking the entities up first. `count` makes that many copies of **each** source. It must be a whole number of at least 1. `offset` is a world-space `{x,y,z}` step that **accumulates**: copy 1 sits one offset from the source, copy 2 sits two, copy 3 sits three. Every copy is placed relative to the **source**, so a run spreads evenly instead of compounding rounding from copy to copy. `name` names each copy, and a `%d` in it becomes the copy's 1-based index — `"pillar_%d"` yields `pillar_1`, `pillar_2`, … Without a `name`, copies are named after their source (`crate_copy`, or `crate_copy_1`, `crate_copy_2`, … for a run). Copies carry the source's render layer. An option key outside the documented set is an error that names it and lists the accepted keys, so a mistyped `conut` is reported instead of returning copies that quietly ignored it. Every call returns the resulting `{ id, name, position, localPosition, rotation, localRotation, eulerAngles, scale, parent }` per copy, in creation order — the copy and the read are the same call.

# entityOps.fromAsset Instantiate an existing asset into the scene — **resolution-first**: pass a name / path / identity string, the tool resolves it and reports the canonical asset it hit, so you never need to know the exact identity up front. ```lua entityOps.fromAsset("@builtin::avatars.humanoid") entityOps.fromAsset("oak_chest", { type = "bundle", position = {2, 0, 0} }) entityOps.fromAsset("gold", { type = "material" }) entityOps.fromAsset("/zero/source/generated/meshes/a_statue.bundle", { link = false }) ``` Dispatch by resolved category: - **bundle / avatar** — instantiated via its own `:instantiate()`. `link` (default true) keeps the live Asset-component link so the source drives the hierarchy; `link = false` bakes the hierarchy into the scene. - **mesh** — a renderable (Model + mesh Collider). - **material** — a sphere carrying the material. - **texture** — a plane sampling the texture (through a fresh unlit material, so it never rewrites another preview). - **anything else** — instantiated through its own `:instantiate()` when it has one, else a legible error. `type` limits the asset search to one category (avoids name clashes). `position` / `rotation` / `scale` place it; `synced` replicates gameplay edits to peers. Returns `{ id, name, resolved = { category, identity, path } }` — `resolved` is the canonical asset your string hit. To spawn from hand-named components instead of an existing asset, use `entityOps.spawn`.

# entityOps.modify Change entity state — one tool for delete / enable / disable / hide / show / temporary / reparent / rename, over one or many entities resolved by **name or id**. ```lua entityOps.modify("debug_probe", { hidden = true }) entityOps.modify({ "probe_a", "probe_b" }, { delete = true }) entityOps.modify("old_character", { enabled = "toggle" }) entityOps.modify("hat", { parent = "player_head" }) ``` Ops: `delete` (removes the whole subtree; wins over everything else), `enabled`, `hidden`, `temporary` (booleans, `"toggle"` flips the current state), `parent` / `unparent` (with `keepWorldTransform`, default true), and `rename` (single target only). Returns one `{ id, name, applied }` record per target. `scene.find` results pipe straight in as targets.

# entityOps.removeComponents Detach component(s) from one or many entities — the counterpart to `entityOps.addComponents`. ```lua entityOps.removeComponents("lamp", "Light") entityOps.removeComponents({ "crate_1", "crate_2" }, { "Physics", "Audio" }) entityOps.removeComponents({ component = { "Light" } }, "Light") entityOps.removeComponents("lamp", "light") -- partial name, resolved ``` Targets take a name or id, a list of them, `scene.find` records, or a **query** resolved for you — so a component is stripped from everything carrying it without naming a single entity. Component names match loosely: the leaf (`"Light"`), the full identity (`"@builtin::components.Light"`), a VFS path, or a case-insensitive partial. The response reports the **canonical** name it resolved to, so a half-remembered name both works and teaches you the real one. A name that could mean several components is an error listing the candidates rather than a guess, and a name matching nothing is an error too — nothing is silently skipped. Every entity comes back as `{ id, name, removed, absent }`: - `removed` — components it carried and lost. - `absent` — components it never had, so nothing happened for them. That split makes a call which changed nothing visible, instead of letting it read like a success.

# entityOps.roots Find the root ancestor of one or many entities — walks each up its parent chain to the top-level entity. ```lua entityOps.roots("player_hand") entityOps.roots({ "wheel_fl", "wheel_fr" }) ``` Targets are entity names or ids (a single one, an array, or `scene.find` records). Returns one `{ target, targetName, root, rootName, depth }` per target; an entity that is already a root reports itself with `depth = 0`.

# entityOps shared Cross-tool helpers for the `entityOps` toolbox — the pieces more than one of its tools reuse. - **Entity resolution** — `resolveEntity` / `resolveTargets` / `toList` turn a name / id / proxy / `scene.find` record (single or a list) into live entity proxies, raising a legible error on anything that doesn't match. - **Subtree removal** — `collectDescendants` / `despawnSubtree` remove an entity and its whole subtree, raising rather than leaving a half-removed tree behind. - **Slot capture** — `captureSlot` snapshots the parent + local transform + name + sync flag an entity occupies, so a replacement can take its exact place. - **Asset resolution** — `resolveAsset` turns a caller's name / path / identity string (or an already-resolved AssetRef) into a resolved asset, reporting the canonical identity/path it hit, optionally limited to one asset category. Tools are thin wrappers over these; the helpers call the engine APIs.

# entityOps.spawn Spawn entities from a template — you name the components they carry and their field values, plus a transform. ## Many entities in ONE call Pass a `{ defaults, items }` list: `defaults` holds what every entity shares, each `items` entry overrides only what differs. A six-walled room is one call, not six. ```lua entityOps.spawn({ defaults = { components = { Model = { model = "cube" }, BoxCollider = {} }, scale = { 4, 3, 0.2 } }, items = { { name = "wall_n", position = { 0, 1.5, -2 } }, { name = "wall_s", position = { 0, 1.5, 2 } }, { name = "wall_e", position = { 2, 1.5, 0 }, rotation = { 0, 90, 0 } }, { name = "wall_w", position = {-2, 1.5, 0 }, rotation = { 0, 90, 0 } }, }, }) ``` - A per-item key wins over the matching `defaults` key. - `components` merges **per component**: an item naming `Model` replaces only that entry and keeps the shared `Collider`. - Every item is validated **before any entity is created** — a typo in the last entry fails the whole call rather than leaving a half-built scene. - An unrecognised key is an error naming the accepted set, at the top level, in `defaults`, and in an item alike. - Returns one `{ id, name, components }` record per item, in item order. ## One entity ```lua entityOps.spawn( { Model = { model = "cube" }, BoxCollider = {} }, { position = {0, 1, 0} }) entityOps.spawn( { Light = { kind = "point", intensity = 5 } }, { name = "lamp", position = {0, 3, 0} }) entityOps.spawn({}, { name = "group" }) -- bare entity, no components ``` Components is a `{ [ComponentName] = { field = value } }` map. Each is an **authored** component (leaf name like `"Model"`, a full identity, or a VFS path) added with its data so it **serializes** — native ECS components are intentionally not exposed here, so you never author something that renders at runtime but vanishes on save. Transform: `position` `{x,y,z}`; `rotation` a `{x,y,z,w}` quaternion or `{pitch,yaw,roll}` euler degrees; `scale` a number or `{x,y,z}`. Also `temporary`, `hidden`, `synced` (replicate gameplay edits to peers), and `attributes`. Returns `{ id, name, components }` with the component leaf names added. To instantiate an existing **asset** (a bundle / avatar / mesh / material / texture) rather than hand-name components, use `entityOps.fromAsset`.

# entityOps.swap Replace one entity with another entity that **already exists in the scene**. The replacement is moved into the target's slot — same parent, local position and rotation, the target's scale (`keepScale = false` opts out) and name (`keepName = false` opts out) — and the target is removed with its whole subtree. ```lua entityOps.swap("DefaultBody", "my_knight") entityOps.swap("placeholder_car", "sports_car", { keepName = false }) entityOps.swap("DefaultBody", "my_knight", { dryRun = true }) ``` Both arguments are entity names or ids. `dryRun = true` reports what would move and what would be removed without mutating. To replace an entity with a content **asset** (a bundle/mesh/…) rather than another scene entity, use `entityOps.fromAsset` (spawn) or `appearance.replaceWithContent` (in-place slot swap).

# entityOps.transform Move, rotate and scale entities that already exist — over one or many entities. ```lua entityOps.transform("lamp", { position = { 0, 3, 0 } }) entityOps.transform({ "wall_n", "wall_s" }, { offset = { 0, 2, 0 } }) entityOps.transform({ name = { "wall" } }, { offset = { 0, 2, 0 } }) entityOps.transform("crate", { rotation = { 0, 45, 0 }, scale = 2 }) entityOps.transform("lamp") -- no ops: a pure read ``` Targets take a name or id, a list of them, `scene.find` records, or a **query** resolved for you — so you can move everything matching `{ name = { "wall" } }` without looking the entities up first. **Absolute** ops carry their space in the name: `position` / `rotation` are world, `localPosition` / `localRotation` are parent-relative, `scale` is a number or `{x,y,z}`. **Relative** ops are `offset` (position delta), `rotate` (applied on top of the current rotation) and `scaleBy` (multiplier). `space` — `"world"` (default) or `"local"` — governs these. `snap` quantizes the resulting position to grid steps. Rotations take a `{x,y,z,w}` quaternion or `{pitch,yaw,roll}` euler degrees, the same forms `entityOps.spawn` accepts. Absolute and relative forms of one channel are exclusive — passing `position` and `offset` together is an error rather than a silent precedence rule. An option key outside the documented set is an error that names it and lists the accepted keys, so a mistyped `positon` is reported instead of returning a successful-looking read of an entity that never moved. Per-entity values in one call: ```lua entityOps.transform({ { target = "wall_n", position = { 0, 1, -5 }, rotation = { 0, 0, 0 } }, { target = "wall_e", position = { 5, 1, 0 }, rotation = { 0, 90, 0 } }, }) ``` Every record is validated and resolved before any of them is applied, so a bad entry fails the whole call rather than moving its siblings and leaving itself behind. Every call returns the resulting `{ id, name, position, localPosition, rotation, localRotation, eulerAngles, scale, parent }` per entity — the mutation and the read are the same call.

# Toolbox (asset type) A toolbox is a namespace folder that groups related `.tool/` children plus shared helpers. Toolboxes are the addressing layer for tools — every tool's identity is `<toolbox>.<name>`, so the toolbox name appears in every callsite. Toolboxes also own a `shared.module/` helper module that the toolbox's tools `require(".shared")` for common utilities (result envelopes, validators, formatters). ## When to use one - You have two or more related tools that belong together (an `anim` toolbox with `play` / `stop` / `list`; an `assets` toolbox with `compose` / `validate`). - You need a shared helper module exclusively used by a tool set. - You want a clean dot-namespaced identity for your tools (`my_tools.foo`, `my_tools.bar`). If you only have one tool and no shared helpers, you still need a toolbox — it's the required parent. ## Where it lives - Source: `/zero/source/.../<Name>.toolbox/` - Identity: `<Name>` (the `.toolbox` suffix strips). - Folder shape (container-style — open child set): - `README.md` — instance documentation. **Required.** - `.metadata` — agent-editable tags + free-form fields. **Required.** - `shared.module/` — optional shared helper module (`init.luau` + `README.md`). - `<x>.tool/` — any number of `.tool/` children. The validator permits unlisted children (`allow_unlisted: true`) so tool subfolders don't need to be declared per-name. ## How to create one ```luau tools.createToolbox({ name = "<Name>", description = "..." }) -- or the generic scaffold: asset.create("toolbox", "<Name>") -- Creates: /zero/source/<Name>.toolbox/ -- README.md (instance README template) -- shared.module/ (ok / fail result-envelope constructors) -- `folder` places it in a subfolder of /source; `into` nests it in a -- resolved `.package`: asset.create("toolbox", "<Name>", { folder = "tools" }) ``` Then add tools under it: ```luau local box = asset.resolve("<Name>.toolbox") asset.create("tool", "<toolName>", { into = box }) ``` ## How it operates 1. **Registration.** Writing into a `.toolbox/` folder indexes the toolbox. It becomes the parent namespace for any `.tool/` children. 2. **Tool identity composition.** Each child `.tool/`'s identity is `<toolbox>.<tool>`. Listing the toolbox's tools enumerates the children. 3. **Shared helpers.** Tools inside the toolbox pull `shared.module/` in via `require(".shared")` (relative require from the tool's `init.luau`). 4. **Hot reload.** Editing `shared.module/init.luau` reloads every tool in the toolbox (they all `require` it). Editing the toolbox folder structure (adding / removing tools) reflects in `tools.list` immediately. ## Discovery - `asset.list("toolbox")` — every registered toolbox. - `asset.inspect("<name>")` — child tools, source, this type README. - `ls /zero/source/<Name>.toolbox` lists the files the folder holds. - `tools.list()` — every tool across every toolbox. ## Authoring conventions - **Per-tool implementation lives in each `<x>.tool/init.luau`.** The tool's full function body — argument validation, the call into engine APIs, the return value — goes in `init.luau` with `--!desc` / `--!arg` / `--!return` / `--!example` annotations above the function. **Every exported function is declared `typed function`** — the keyword compiles to the runtime argument check, so a plain `function` accepts any input and reports success on garbage. Do NOT make `init.luau` a one-line forwarder onto a function defined in `shared.module/`. - Keep `shared.module/` thin: result envelope constructors (`shared.ok(value, formatted)`, `shared.fail(message, exitCode)`), argument validators, common formatters — anything genuinely used by more than one tool. Per-tool logic does NOT belong here. - Group by domain, not by surface — `assets` toolbox holds asset operations, `entity` toolbox holds entity operations. Tools that feel unrelated probably want different toolboxes. - Document the toolbox's surface in `README.md` — what problem space it covers, who calls into it, any shared invariants. ## Common pitfalls - **Missing parent toolbox.** Tools cannot exist outside a toolbox. Always scaffold the toolbox first. - **Cross-toolbox shared.** Each toolbox has its own `shared.module/`. Don't try to share helpers across toolboxes; if you need cross-toolbox helpers, factor them into a standalone `.module`. - **Toolbox identity.** Strip the `.toolbox` suffix in identity references (`my_tools`, not `my_tools.toolbox`). ## Related types - `.tool` — the required child(ren) of a toolbox. - `.module` — for cross-toolbox utilities. ## In the Inspector Tools: how many tools the box holds, whether it ships a shared module, what each tool does, and a link to each tool.

# edui.shell (module) The editor dock shell on the CSS-parity `ui.*` surface. One edui app owns a `ui.*` native `dockArea` whose children are a `dockPanel` per registered edui panel — real `egui_dock` tabs, splits and drag, with the arrangement persisting across rebuilds because the dockArea and each dockPanel carry a stable `id`. ## Why a separate registry The shell keeps its own panel registry (`addPanel` / `removePanel` / `panelsSorted`), distinct from the deprecated zui `editor.registry`. That keeps the zui editor completely untouched while panels migrate to edui one at a time: the zui dock renders the zui-framework panels it always has, and the edui shell renders the edui panels registered here. The two registries fold into one at cutover, when the zui dock is retired. ## One app, one reactive loop `App.rebuild` sets the shell as the building app before it calls `buildShell`, so a panel's `build()` — which uses `edui.current()` to register its closures — wires every callback onto the ONE shell app. All interaction for every panel flows through the shell's single callback env, and a click anywhere rebuilds the whole dockArea. That is why the shell needs no per-tab scheduler (unlike zui's `dockApp`): the edui App is the scheduler. ## Usage ```lua local edui = require("@builtin::modules.edui") edui.shell.addPanel{ id = "entities", title = "Entities", order = 10, build = function() return edui.panel{ title = "Entities", body = edui.tree{ ... } } end, } edui.shell.mount() -- registers the screen on the EditorUI layer -- each editor-update frame: edui.shell.update(dt) -- liveness rebuild every `refresh` seconds ``` `mount(opts?)` takes `{ refresh? }` (seconds between liveness rebuilds, default 0.5). `refresh()` forces an immediate rebuild; `unmount()` tears the screen down but keeps the panel registrations for a later `mount`.

# capture The newest frame a capture produced on this engine, drawn full-pane, with the shot's number, where it was rendered from, which pass it holds and its pixel size on the toolbar. The frames come from `@builtin::tools.capture.feed`, which every capture publishes to. A frame still on the GPU is drawn from its own render target, so the picture is the one the engine already holds; a capture given a `path` is drawn from the file it wrote there. The `watch` layout puts this tab under the scene, so the person at the window sees the same frame the agent got.

# 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.