Doctor reference

Loom -> Doctor is the first stop when something isn’t working. It runs a series of self-checks and writes a report to the Unity Console. Loom -> Status Window shows the same checks in a dockable overlay that updates live. This page is the reference for what each check means.

Node.js found

What it checks: That node is on the PATH of the shell Unity launched from.

Red means: Node isn’t installed, or isn’t visible to the Editor’s environment.

Fix: Install Node.js 20 or newer from nodejs.org, then relaunch Unity so it picks up the updated PATH.

npm found

What it checks: That npm is on the PATH.

Red means: npm is missing, usually because Node isn’t installed.

Fix: npm ships with Node.js. Reinstall Node and relaunch Unity.

Vite dev server

What it checks (Editor only): That the UI dev server is running and has reported its URL.

“not running” before you press Play is normal, the dev server starts with Play mode. If it stays down during Play, it failed to start (commonly a busy port held by a leftover server, or a UI app that won’t build).

Fix: Loom -> Restart Dev Server. If it still won’t come up, check the Console for [Loom dev] lines.

Native plugin

What it checks: That the native plugin binary for your platform (Windows or macOS) is present in the installed package.

Red means: The package is missing the binary for your platform, or your platform isn’t supported in this release.

Fix: Reinstall the Unity package, then restart Unity. See Supported platforms for the platforms this release ships.

Firefox DevTools

What it checks: Whether Firefox is installed, which Loom uses for browser DevTools (inspecting your UI’s DOM, console, and network while it runs inside the game).

Yellow/absent means: Firefox isn’t installed. This is optional, Loom works fine without it; you just can’t open DevTools against the running UI.

Fix: Install Firefox if you want DevTools, then use Loom -> Open Browser DevTools while in Play mode.

Generated bridge.d.ts

What it checks: That the generated TypeScript types (<ProjectRoot>/UI/generated/bridge.d.ts) exist, and reports how recently they were written.

Red means: The types haven’t been generated yet, your UI code has no typed view of the bridge.

Fix: Recompile your C# (the types regenerate automatically), or run Loom -> Regenerate Types.

Build cache

What it checks: Whether the production UI build (<ProjectRoot>/UI/dist) is older than your UI source. Only relevant when you’ve made a player build; in dev mode the live dev server is used instead.

Red means: UI/dist is stale relative to UI/src, a player build would ship outdated UI.

Fix: Loom -> Build UI for Player before building your game. See Player builds.