Live diagnostics for Stimeo UI stimeo--* markup in HTML/ERB — the same engine as npx -y stimeo-ui check, running as you type. Stimeo UI is a headless Stimulus UI framework for Ruby on Rails: behavior-only, accessible components driven by HTML attributes.

Unknown names with "Did you mean …?" hints: controllers, targets, values, and data-action methods.
Structure: missing required targets, orphan targets.
Accessibility: author-supplied ARIA the controller cannot add at runtime (missing or invalid values), keyboard-focusability prerequisites, and controller-managed ARIA you should not hardcode.
Quick fixes (💡): unambiguous corrections — a typo'd controller/target/ action/idref token, a single-valued ARIA attribute — apply in one click.
Completions: controller identifiers inside data-controller and data-action, target names inside data-stimeo--*-target, action methods after # — all driven by the manifest, so they always match the installed version.
Hovers: the full authoring contract of any stimeo--* identifier under the cursor — targets (with required ones), value/action/event names, and the accessibility, keyboard, and controller-managed-ARIA requirements the Inspector checks.

No language server and no setup: the checker is bundled into the extension and works out of the box. Diagnostics carry the same stable codes as the CLI (unknown-controller, missing-aria, …), so data-stimeo-ignore opt-outs behave identically.

Manifest resolution

Diagnostics, completions, and hovers are driven by the controller manifest, resolved per document:

stimeo.manifestPath (explicit) — when set, always used (absolute, or relative to a workspace folder).
Nearest workspace install (preferred) — walking up from the document's directory to its workspace root (ESLint-style), the first node_modules/stimeo-ui/dist/inspector/manifest.json wins. A Rails app nested inside a monorepo is checked against its own installed version, not a sibling's. Single files opened without a workspace walk up to the filesystem root.
Bundled snapshot (fallback) — the manifest captured when the extension was built.

A manifest whose shape the bundled engine cannot consume (e.g. a much older package version) is skipped in favor of the next tier instead of breaking diagnostics. Installed manifests are watched, so an npm install upgrade re-checks open documents automatically; if your setup excludes node_modules from file watching (files.watcherExclude), run “Stimeo UI: Reload manifest” from the command palette instead. The "Stimeo UI" output channel logs which manifest is active.

Settings

Setting	Default	Effect
`stimeo.enable`	`true`	Toggle all features from this extension.
`stimeo.manifestPath`	`""`	Explicit manifest to check against; overrides automatic resolution.