internal/preset/resolve.go::ResolveVersion(ctx, t) hits the right registry per backend:

Backend	Endpoint
npm-distributed packages	registry.npmjs.org/<pkg>/latest
brew formulas	formulae.brew.sh/api/formula/<name>.json
node-lts	nodejs.org/dist/index.json (first LTS entry)
curl bash-script installs	skipped
opaque mise-only plugins	skipped

The tree picker fans these out via tea.Cmd on Init, then falls back to the parsed PlannedVersion (parsed from @<ver> in the install command) while in flight. Per-tool timeout is 3 s — never blocks tree render.

Render order

1. Picker mounts → every tool shows its parsed PlannedVersion (v? if none).
2. Concurrent registry probes fire.
3. Each tea.Msg that returns updates that one row in place.
4. At 3 s, any in-flight probe is cancelled and the row keeps showing the parsed pin.

This means the picker is interactive immediately, and "live" versions populate over the next ~1 s without any spinner UI.

Why not cache

The picker is the only place that uses the live version. The data goes stale fast (npm packages publish constantly), and a stale cache would surface as "your tree picker said v1.2 but I just installed v1.4" — confusing at best. Re-querying on every launch keeps the displayed value true.

Adding a new backend

Add a switch case in ResolveVersion. Inputs: Tool struct (Name, Source, Pkg, etc). Output: (string, error). Honour the context deadline.