Not Exposed

TL;DR: If a .NET / Unity symbol does not have a binder link and is not stubbed by the WASI layer, calls fall through to BindingManager.FillNonLinkedWithEmptyStubs and silently no-op. This page enumerates the conspicuous absences and the CVR-approved replacements.

Rule of thumb

• Allow-list by generation — only types that have a file in CVR-GameFiles/WasmBinder.Links.*/ or a manual binding in WasmBinder.LinksManual.UnityEngine/ or a hand-written binding in WasmScripting/*Bindings.cs are reachable.
• Anything else is either (a) filled with an empty stub at instantiation time or (b) filtered out by the CCKWasmModule shim at compile time.

ScriptableObject

Not supported. A [SerializeField] public MyScriptableObject data; field on a WasmBehaviour is skipped by the serializer — it doesn’t cross the build boundary and is null at runtime.

Substitutions:

• Replace shared data with a [WasmSerialized] custom class on a WasmBehaviour component, or plain fields on a “config” WasmBehaviour that lives on a well-known GameObject in your content.
• For inspector-editable asset-style data, pack it into arrays of serializable fields on the behaviour.

UnityEngine.Application

Not bound. Common substitutions:

• Application.platform, .version, .productName — not available. If you need to branch, use the CCK CVR_SCRIPTING_CONTEXT_* preprocessor defines at compile time.
• Application.Quit() — not available. CVR controls the process lifetime.
• Application.isPlaying — not available. You are always running; there is no editor play mode from the guest’s perspective.

UnityEngine.Input

Not bound. CVR is VR-first, so hooking into keyboard/mouse at this level would be misleading anyway. Substitutions:

• Interactions — use CVR’s CVRPointer, CVRInteractable, or bindable CCK components with persistent UnityEvents. See Unity Events Rewiring.
• VR controller buttons — surfaced via CCK input components (e.g. CVRInputManager / CCK AvatarInput) and the OnInputReady game event, not via UnityEngine.Input.

UnityEngine.Screen

Not bound. Screen size / orientation / resolution are not meaningful for a script that doesn’t own the window — they belong to CVR.

UnityEngine.PlayerPrefs

Not bound. Substitution:

• World-scoped persistence — File Storage (requires world permission).
• Per-avatar or per-prop persistence — not directly supported. Use network messages to sync transient state across clients and rely on the host for instance lifetime.

UnityEngine.Resources / AssetBundle

Not bound. Loading new assets at runtime from outside the original CCK upload is forbidden — otherwise the content-integrity model (signed uploads, per-content permissions) breaks.

• You can still reference any asset that shipped with your avatar/world/prop via regular field references (serialized UnityEngine.Object fields).

UnityEngine.Application / OnApplicationX events

Already covered in Events. Disallowed:

• OnServerInitialized, OnConnectedToServer
• OnGUI
• OnApplicationQuit, OnApplicationFocus, OnApplicationPause

Define them — they will be detected and ignored.

UnityEngine.SceneManagement (runtime)

Only the Scene struct is bound. Not bound:

• SceneManager.LoadScene*
• SceneManager.UnloadScene*
• Scene instantiation APIs

CVR manages world scene loading itself (portals, instance joins). Scripts observe scene state — they do not drive it.

System.IO

Not bound. The WASI filesystem imports (fd_close, fd_read, fd_write, fd_seek, fd_filestat_get, fd_fdstat_get, fd_prestat_get, …) are stubbed to return 8 (WASI EBADF). path_open / path_filestat_get / path_readlink / path_unlink_file return 0 but never produce data. environ_get / environ_sizes_get return 0 with empty output. clock_time_get is implemented (real-time and monotonic clocks), random_get + mono_wasm_browser_entropy fill the buffer with Random.NextBytes. See CVR-GameFiles/WasmScripting/WasmStubs.cs.

• Persistent state — File Storage.
• In-module resources — pack them into the .wasm via dotnet publish embedded resources and read via System.Reflection.Assembly.GetManifestResourceStream. (Requires enableReflection on the descriptor.)

System.Net / System.Net.Sockets

Not bound. No raw TCP / UDP.

• Player-to-player messaging — Networking.
• External HTTP — gated by the HttpApiAllowed + HttpAllowedDomains world permissions. See World Permissions.

System.Diagnostics.Process

Not bound. No subprocess spawning. Wasmtime would refuse anyway — WASI’s process APIs are only stubs.

System.Reflection.Emit

Effectively disabled. The default csproj sets <IlcDisableReflection>true</IlcDisableReflection>, which strips reflection metadata during NativeAOT compilation. Emit-style dynamic codegen is fundamentally incompatible with the AOT toolchain.

• If you need limited reflection, set CCKWasmProjectDescriptor.enableReflection = true. The module size increases significantly.

UnityEngine.GameObject.Find / FindObjectOfType

Not generally bound (check GameObjectLinksManual.cs for the subset that is). Even if available they would be forbidden by the scope check: results outside your content root are ScopeContext.ExternalContent and most write operations demand Self.

• Wire references at design time via serialized public fields.
• Use hierarchy traversal from this.transform (Transform is bound) to find children.

UnityEngine.Instantiate (prefab instantiation)

Restricted. Manual binding in ObjectLinksManual.cs gates instantiation behind scope + permissions. In practice:

• Instantiating a prefab inside your own content root is fine.
• Instantiating into external content (another player’s avatar, the world if you’re an avatar/prop) is rejected.

UnityEngine.Coroutine start

Partially supported: Coroutine is a type that can be held, but StartCoroutine exposure depends on the GameObjectLinksManual.cs surface. Prefer:

• Update / FixedUpdate for periodic work.
• A lightweight state machine you tick yourself rather than multiple coroutines.

Time.deltaTime write

Read is fine (Time is bound). Writes are not accepted — Time.timeScale and similar mutators are either not bound or gated away.

UnityEngine.Application.persistentDataPath / streamingAssetsPath

Not bound. There is no notion of a per-session working directory in the sandbox. Use File Storage.

Any [DllImport] / P/Invoke

Not usable. The generated .wasm has no loadable native libraries — only the WASM imports CVR defines in its linker. P/Invoke declarations compile but fail to link.

Threads / Tasks / async

• WASM threads — disabled (WasmManager.Config does not set WithWasmThreads).
• Task / async — you can use Task and async/await at the C# level (the NativeAOT runtime supports it), but all work runs on the WASM single thread. Awaits serialize into continuations on the same call; they do not actually yield to other Unity work.
• Thread.Sleep — not bound (there’s nothing to sleep to — you’d block the single thread).

Globalization and culture

Reflection-dependent culture / formatting APIs may throw or behave unexpectedly under IlcDisableReflection. Stick to invariant-culture formatting and explicit number/date parsers.

Env vars / command line

WASI environ_get / environ_sizes_get return empty. There is no command line for a WASM module inside CVR.

Summary

You want to …	Use
Read / write a file	File Storage (world, permissioned)
Call an HTTP API	CCK WasmModule HTTP helpers, gated by world permissions
Move the local player	CVR_LocalPlayer_* (world only)
Send data to other clients	Networking
Persist state across sessions	File Storage (world) or network-sync with instance owner
Read the user’s identity	CVR_Player_GetUserId + AccessUserIdentity permission; CVR_Player_GetUsername no longer needs a permission
Load an asset at runtime	Reference it at design time; runtime dynamic loading is forbidden
Schedule work on another thread	Not possible — WASM threads disabled

Related

• CVR Host Functions — the full set of what IS exposed.
• Permissions — why something might be exposed yet throw.