# HELIX Docs

> Developer documentation for HELIX, a virtual world platform: build, publish and sell worlds and items on the web (HELIX Instant) or in Unreal. The CLI and MCP reference pages are generated from the published `@hypersoniclabs/helix-cli` and `@hypersoniclabs/helix-mcp` packages, so they match the shipped tools.

Machine-readable sources:

- [CLI command tree (JSON)](https://docs.helixgame.com/reference/cli.json)
- [MCP tools with input schemas (JSON)](https://docs.helixgame.com/reference/mcp.json)
- [Web SDK members (JSON)](https://docs.helixgame.com/reference/sdk.json)
- [Full text of every page](https://docs.helixgame.com/llms-full.txt)

Agents that run the HELIX MCP server should prefer it: it serves versioned docs and skills (`get_started`, `read_doc`, `read_skill`) matching the exact version in use.

## Pages

- [Feature matrix](https://docs.helixgame.com/docs/feature-matrix): Exactly what's available in each runtime. The Platform API is identical; runtimes differ only in rendering, input, and networking.
- [HELIX Documentation](https://docs.helixgame.com/docs): The unified SDK and platform reference for building virtual worlds on HELIX — across web and Unreal Engine.
- [Connect Claude Desktop](https://docs.helixgame.com/docs/cli/connect-claude-desktop): Add HELIX as a local MCP server in Claude Desktop so an AI agent can validate and publish worlds.
- [HELIX CLI](https://docs.helixgame.com/docs/cli): Scaffold, validate and publish HELIX worlds, items, devices and vehicles from the terminal. The same commands humans and AI agents use.
- [MCP server for AI agents](https://docs.helixgame.com/docs/cli/mcp): The HELIX Model Context Protocol server gives AI coding agents typed tools to discover, validate, build and publish on HELIX.
- [Publish an item from a GLB](https://docs.helixgame.com/docs/cli/publish-a-wearable): Seal a .glb as an immutable Continuum Package, turn it into an Item, and optionally open a Marketplace offer. Also where wearables and other character add-ons fit.
- [Build your first multiplayer world](https://docs.helixgame.com/docs/guides/first-multiplayer-world): Start from the multiplayer scaffold, add one server-validated action, and publish. HELIX multiplayer is declarative, so there is no server code to write.
- [Guides](https://docs.helixgame.com/docs/guides): Task-oriented recipes that combine the Platform API and a runtime to ship something real. Most show web and Unreal side by side.
- [Persist player data](https://docs.helixgame.com/docs/guides/persist-player-data): Keep player progress between sessions with persistent player variables, or store a player's own data with the Data Store.
- [Sell something for LIX](https://docs.helixgame.com/docs/guides/sell-item-for-lix): Register a product on your world, ask the player to buy it, and read back what they own. The shell charges LIX; your world never handles money.
- [Choose your runtime](https://docs.helixgame.com/docs/introduction/choose-your-runtime): Web or Unreal? A quick decision guide and what each path gives you.
- [How HELIX works](https://docs.helixgame.com/docs/introduction/how-helix-works): The core nouns — World, Build, Instance, Player, Event — and the lifecycle of a player opening a world.
- [What is HELIX?](https://docs.helixgame.com/docs/introduction): HELIX is an engine-agnostic virtual-world platform. Create, publish, host, and monetize multiplayer 3D worlds — playable instantly from a single link.
- [Platform vs Engine SDK](https://docs.helixgame.com/docs/introduction/platform-vs-engine): The single most important concept in HELIX — what belongs to the engine-agnostic Platform API versus an engine-specific runtime.
- [Quickstart](https://docs.helixgame.com/docs/introduction/quickstart): From an empty folder to a published, multiplayer HELIX Instant world in about ten minutes, using the real helix CLI.
- [Apps & the manifest](https://docs.helixgame.com/docs/phone/app-model): What a Helix Phone app is, the manifest that describes it, app IDs, content ratings, and the full set of built-in apps.
- [The App Store](https://docs.helixgame.com/docs/phone/app-store): How third-party phone apps are registered, installed, and managed — the manifest, install lifecycle, and where the publishing flow is today versus where it's going.
- [Example app: World Postcard](https://docs.helixgame.com/docs/phone/example-app): A complete, real phone app built on the Helix Phone SDK — pick or capture a photo, tag it with your current world, save a draft, unlock a premium frame via IAP, then post to Helixgram, notify, and share.
- [In-app purchases](https://docs.helixgame.com/docs/phone/in-app-purchases): Sell consumables, unlocks, and subscriptions inside a phone app — priced in LIX, idempotent, and declared in your manifest.
- [The Helix Phone](https://docs.helixgame.com/docs/phone): A universal smartphone that travels with every player across worlds — with built-in apps and an app store for third-party developers building on the Helix Phone SDK.
- [Keeping these docs in sync](https://docs.helixgame.com/docs/phone/keeping-docs-in-sync): How the Phone SDK docs stay current with the code — an automated drift detector that compares the live SDK surface on the helix3 branch against the documented snapshot and flags anything new, changed, or removed.
- [Permissions & consent](https://docs.helixgame.com/docs/phone/permissions): The 12 Phone permission scopes, how apps declare them, how players grant them, and the audit trail behind every grant.
- [Proposed & in-progress](https://docs.helixgame.com/docs/phone/proposed): Capabilities that are mocked, partial, or not yet built — plus proposed new SDK surfaces to round out the Helix Phone. Everything here is clearly labeled and not yet guaranteed.
- [Phone SDK reference](https://docs.helixgame.com/docs/phone/reference): Every Helix Phone SDK namespace and method — runtime, account, permissions, storage, notifications, media, camera, wallet, payments, contacts, messages, calls, presence, social, feeds, ui, and lifecycle.
- [Runtime & the bridge](https://docs.helixgame.com/docs/phone/runtime-and-bridge): How phone apps actually run — the sandboxed iframe model, the postMessage bridge, the bootstrap snapshot, and lifecycle events.
- [Unreal SDK](https://docs.helixgame.com/docs/unreal-sdk): The HELIX Platform API inside Unreal Engine — the same functions in C++, Blueprint, and Lua, plus engine-native networking.
- [Languages](https://docs.helixgame.com/docs/unreal-sdk/languages): Setup and the same HELIX call written in C++, Blueprint, and Lua.
- [Networking](https://docs.helixgame.com/docs/unreal-sdk/networking): How multiplayer works in Unreal worlds — engine-native dedicated servers with HELIX replication wrappers. Distinct from the web multiplayer stack.
- [Reference](https://docs.helixgame.com/docs/unreal-sdk/reference): A sample of the planned C++ API reference for the HELIX Unreal plugin. Not generated or verified against the plugin yet.
- [Analytics event contract](https://docs.helixgame.com/docs/platform-api/analytics): HELIX-owned event capture, storage, rollups, and creator-safe analytics, with PostHog as an internal analysis surface.
- [Authentication & Identity](https://docs.helixgame.com/docs/platform-api/authentication): One HELIX account across every world. How world sessions, room credentials, guests, and permissions work.
- [Collectibles](https://docs.helixgame.com/docs/platform-api/collectibles): Scarce, serialized universal items that trade peer-to-peer for LIX. How they differ from ordinary items, and how worlds use them.
- [Content rating & maturity](https://docs.helixgame.com/docs/platform-api/content-rating): Every item and world declares a maturity rating. The platform gates discovery by it, and creators attest to it at publish time.
- [Data Store](https://docs.helixgame.com/docs/platform-api/data-store): Durable, authoritative per-world key–value storage. The source of truth for anything that must survive a session.
- [Platform API overview](https://docs.helixgame.com/docs/platform-api): The engine-agnostic surface of HELIX — identity, economy, storage, inventory, and social — exposed identically on every runtime.
- [Live wearable and Unreal contract](https://docs.helixgame.com/docs/platform-api/interactive-items-live-contract): The deployed Universal Item upload, finalize, status, download, and Unreal rendition contract, audited against helix3.
- [Interactive Universal Items](https://docs.helixgame.com/docs/platform-api/interactive-items): Production implementation contract for portable items with authoritative behavior, typed state, character abilities, and default-on Vault publication.
- [Inventory & Items](https://docs.helixgame.com/docs/platform-api/inventory): Universal items that work across worlds and runtimes, and the four-tier execution model that decides what the client may do and what the server must own.
- [LIX & Economy](https://docs.helixgame.com/docs/platform-api/lix-economy): LIX is HELIX's hard currency. The wallet, in-world purchases, the marketplace, and the rules that keep value stable — all server-authoritative.
- [Memory Store](https://docs.helixgame.com/docs/platform-api/memory-store): Volatile, low-latency storage shared across all instances of a world. TTL-required. Great for leaderboards, matchmaking, and hot counters — never the source of truth.
- [Social & Presence](https://docs.helixgame.com/docs/platform-api/social): Presence, parties and matchmaking that ship today, and the planned friend graph (Helix.social).
- [Universal Avatar](https://docs.helixgame.com/docs/platform-api/universal-avatar): Cross-runtime avatar loadouts, equipment slots, and placeholder-compatible socket rules for Web and Unreal.
- [Unreal dual-format wearable test](https://docs.helixgame.com/docs/platform-api/unreal-wearable-test): A sendable end-to-end test for publishing one wearable with Web and cooked Unreal package renditions.
- [World media (thumbnail, preview image, preview video)](https://docs.helixgame.com/docs/platform-api/world-media): Set a world's card artwork and the images + YouTube video that play in its detail carousel. Images upload through a presigned PUT; video is referenced from YouTube, not hosted.
- [Web SDK](https://docs.helixgame.com/docs/web-sdk): The TypeScript runtime for HELIX Instant worlds. Identity, wallet, storage, inventory, multiplayer and voice for a world that runs in the browser.
- [Multiplayer & Networking](https://docs.helixgame.com/docs/web-sdk/multiplayer): How HELIX web worlds share a space and a game. A platform-owned, server-authoritative room runs rules you declare in helix.json. Web-runtime only.
- [Reference](https://docs.helixgame.com/docs/web-sdk/reference): The Web SDK API reference is generated from the published package type declarations.
- [Avatars, characters and animation](https://docs.helixgame.com/docs/cli/mcp-tools/avatars): Avatars, NPCs, looks, gestures, animation and locomotion packs.
- [Import bridge](https://docs.helixgame.com/docs/cli/mcp-tools/bridge): Detect, plan and run imports from other engines and file formats.
- [Continuum and packages](https://docs.helixgame.com/docs/cli/mcp-tools/continuum): Publish, pull and inspect Continuum packages and receipts.
- [Devices](https://docs.helixgame.com/docs/cli/mcp-tools/devices): Create, validate and test interactive devices.
- [Generation](https://docs.helixgame.com/docs/cli/mcp-tools/generation): Generate assets, images, audio, materials and environments.
- [Getting started and account](https://docs.helixgame.com/docs/cli/mcp-tools/getting-started): Docs, skills, sign-in and environment checks.
- [MCP tool reference](https://docs.helixgame.com/docs/cli/mcp-tools): All 124 tools registered by helix-mcp 0.2.16-helix3.209, generated from the server.
- [Items and distribution](https://docs.helixgame.com/docs/cli/mcp-tools/items): Search, publish, delist and distribute universal items.
- [Vehicles](https://docs.helixgame.com/docs/cli/mcp-tools/vehicles): Check, simulate, preview and publish vehicles and vehicle add-ons.
- [Worlds](https://docs.helixgame.com/docs/cli/mcp-tools/worlds): Scaffold, validate, publish and measure worlds, terrain, placements, achievements and products.
- [helix achievement](https://docs.helixgame.com/docs/cli/reference/achievement): Register and manage a world's achievements (the badges `awardAchievement` and criteria unlocks grant)
- [helix add-interactable](https://docs.helixgame.com/docs/cli/reference/add-interactable): Resolve a Marketplace interactable, verify and vendor its bundle, then generate client/server glue
- [helix assets](https://docs.helixgame.com/docs/cli/reference/assets): Discover, install, and generate HELIX platform assets
- [helix bake-body-regions](https://docs.helixgame.com/docs/cli/reference/bake-body-regions): One-off: bake a per-vertex `_REGION` attribute onto a HELIX canonical base body GLB, so a character add-on's hide op can suppress the exact body region it covers with zero extra draw calls (no mesh sp
- [helix bake-lighting](https://docs.helixgame.com/docs/cli/reference/bake-lighting): Bake a world's keyframed lighting field from its BUILT bundle (headless, minutes) and point its visual contract at the artifact
- [helix balance](https://docs.helixgame.com/docs/cli/reference/balance): Show your LIX balance: available, held by open jobs, and total
- [helix bridge](https://docs.helixgame.com/docs/cli/reference/bridge): Universal, plugin-driven import pipeline for assets, characters, scenes, and engine projects
- [helix character](https://docs.helixgame.com/docs/cli/reference/character): Character asset tools — convert biped GLBs and retarget GLB/FBX animations
- [helix city](https://docs.helixgame.com/docs/cli/reference/city): City pipelines: the neutral city source every importer writes and every generator reads
- [helix continuum](https://docs.helixgame.com/docs/cli/reference/continuum): Publish exact-CID Packages, Builds, Listings and World Releases through one resumable creator pipeline
- [helix dev](https://docs.helixgame.com/docs/cli/reference/dev): Serve a BUILT world under a SIMULATED HELIX shell — offline, no login, no backend.
- [helix device](https://docs.helixgame.com/docs/cli/reference/device): Create, validate, and simulate GLB-backed HELIX Devices
- [helix doctor](https://docs.helixgame.com/docs/cli/reference/doctor): Health check: login state + whether the @helix toolchain (CLI/MCP/SDK/manifest) is up to date
- [helix export-placement-request](https://docs.helixgame.com/docs/cli/reference/export-placement-request): Export a reserved placement request bound to the final multiplayer bytes; no reservation or publication
- [helix gesture](https://docs.helixgame.com/docs/cli/reference/gesture): Gesture (pose-DSL) tools — measure what a clip does to the body without a browser
- [helix glb](https://docs.helixgame.com/docs/cli/reference/glb): GLB utilities — inspect and repair a binary glTF before it is published
- [Command reference](https://docs.helixgame.com/docs/cli/reference): Every command in helix 0.1.27-helix3.551, generated from the CLI itself.
- [helix init](https://docs.helixgame.com/docs/cli/reference/init): Scaffold a complete, build-ready HELIX Instant world project (or, with --ability, a humanoid-character ability)
- [helix install](https://docs.helixgame.com/docs/cli/reference/install): Resolve this v0.2 world's system/ability pins, download their code, and write installed.json + helix.lock.json
- [helix item-def](https://docs.helixgame.com/docs/cli/reference/item-def): Interactive item definitions — scaffold and validate a descriptor offline, then inspect an existing Package-backed definition
- [helix item](https://docs.helixgame.com/docs/cli/reference/item): Package-backed Items, inventory-safe version updates and acquisition routes
- [helix jobs](https://docs.helixgame.com/docs/cli/reference/jobs): List your generation jobs with what each one cost — the answer to "what was I charged for?" after a failure
- [helix list-abilities](https://docs.helixgame.com/docs/cli/reference/list-abilities): List the abilities published on HELIX Instant
- [helix list-systems](https://docs.helixgame.com/docs/cli/reference/list-systems): List the systems published on HELIX Instant
- [helix login](https://docs.helixgame.com/docs/cli/reference/login): Log in to HELIX (opens your browser); use --token for CI/headless
- [helix logout](https://docs.helixgame.com/docs/cli/reference/logout): Remove the stored client token
- [helix look](https://docs.helixgame.com/docs/cli/reference/look): Read and save Presets — dressed-character presets (API identifier: build)
- [helix model](https://docs.helixgame.com/docs/cli/reference/model): Build procedural models written as .model.js programs
- [helix pack](https://docs.helixgame.com/docs/cli/reference/pack): Locomotion packs — scaffold and validate replacement movement clips offline before sealing an add-on Package
- [helix placements](https://docs.helixgame.com/docs/cli/reference/placements): Bake and inspect instanced placements: prototypes, solid records and rule-generated scatter
- [helix preview-video](https://docs.helixgame.com/docs/cli/reference/preview-video): Set (or clear) a world's preview video from a YouTube link
- [helix product](https://docs.helixgame.com/docs/cli/reference/product): Register world-local consumables, passes and currencies.
- [helix publish-interactable](https://docs.helixgame.com/docs/cli/reference/publish-interactable): Publish a validator-gated interactable bundle and link its official free Marketplace item
- [helix publish-package](https://docs.helixgame.com/docs/cli/reference/publish-package): Publish a system / ability / asset-pack bundle (requires an admin account)
- [helix publish](https://docs.helixgame.com/docs/cli/reference/publish): Publish a world to HELIX Instant
- [helix scene](https://docs.helixgame.com/docs/cli/reference/scene): Bring a captured world into the scene sources a HELIX world streams
- [helix screenshot](https://docs.helixgame.com/docs/cli/reference/screenshot): Capture headless screenshots of a built world via its in-page screenshot helper (Playwright)
- [helix terrain](https://docs.helixgame.com/docs/cli/reference/terrain): Author the ground a scene world stands on: generate or import a landform, bake its splats, inspect the result
- [helix thumbnail](https://docs.helixgame.com/docs/cli/reference/thumbnail): Attach or clear a world's custom thumbnail/preview image (fills the generated-placeholder slot)
- [helix unreal](https://docs.helixgame.com/docs/cli/reference/unreal): Prepare Unreal 5.8 projects for publishing to HELIX
- [helix update-interactable](https://docs.helixgame.com/docs/cli/reference/update-interactable): Re-resolve an installed Marketplace interactable and move its instances to the current bundle in place (same namespace, same placement)
- [helix validate-bundle](https://docs.helixgame.com/docs/cli/reference/validate-bundle): Validate an ability bundle against the frozen ability-v1 contract (the same module the runtime loader runs)
- [helix validate](https://docs.helixgame.com/docs/cli/reference/validate): Validate a world bundle locally (same rules the server enforces)
- [helix vault](https://docs.helixgame.com/docs/cli/reference/vault): Discover sealed Continuum Packages — including Presets — through the public Vault catalog
- [helix vehicle](https://docs.helixgame.com/docs/cli/reference/vehicle): Validate and preview a Universal Vehicle before Package publication
- [helix verify-subpath](https://docs.helixgame.com/docs/cli/reference/verify-subpath): Load a BUILT bundle served from a nested path (the only way a published world is ever served) and fail on a throw, a 404, or a blank render
- [helix whoami](https://docs.helixgame.com/docs/cli/reference/whoami): Show the current login status
- [helix world](https://docs.helixgame.com/docs/cli/reference/world): World tools — create the world's identity before publishing, and measure a built world's geometry as data instead of eyeballing screenshots
- [API reference](https://docs.helixgame.com/docs/web-sdk/api): Generated from @hypersoniclabs/helix-sdk 0.1.11-helix3.147.