Main Engineering
Main Engineering is a tab available in every LCARdS card editor. It gives you a live window into the core systems powering that card — inspect runtime state, browse tokens, manage data sources, and trace config origins without leaving the editor.
Opening Main Engineering
- Click the pencil (edit) icon on any LCARdS card
- Select the Main Engineering tab in the editor panel
Panels
Data Sources
Manage the DataSources attached to this card.
- Browse all registered sources — see each source's current value, entity, update rate, and history buffer size
- Create a new source — define a new entity subscription with history preloading and a processing pipeline
- Edit an existing source — change entity, update interval, history settings, or add/modify processors
- Remove a source — detach a DataSource from this card
- Live values — values update in real time as entity state changes
This is the fastest way to set up a chart or gauge without hand-writing DataSource YAML. Create the source here, then reference it in your card config as {ds:source_name}.
Rules Browser
Inspect the Rules Engine from this card's perspective.
- All active rules — shows every rule currently in the system (from packs, config, and the rules helper)
- Rules affecting this card — highlights rules whose target tags, IDs, or types match this card
- Current patches — shows exactly which style patches are being applied right now, and by which rule
- Rule state — shows whether each rule's conditions are currently met
Use this to debug unexpected styling — if a card looks wrong, check here to see what rules are patching it.
Theme Browser
Explore the active Theme token tree live.
- Browse all tokens — the full token namespace tree, in categories (colours, typography, spacing, components, etc.)
- Current values — tokens are shown with their resolved values from the active theme
- Search — filter by name or value
- Copy — click any token to copy its
{theme:token.path}reference ready to paste into card config
Finding the right token
Open Theme Browser while editing a card. When you find the colour or size you want, click to copy its path — then paste it directly into your YAML or Config field.
Provenance Tracker
See the effective runtime configuration for this card and trace exactly where each value came from.
Every config value a card uses could come from one of several sources — the card's own YAML, a preset, a rule patch, or a default from the core system. Provenance Tracker shows which source contributed each individual property.
| Source layer | Description |
|---|---|
| Card config | Direct values from the card's own YAML |
| Preset | Values provided by the active preset: |
| Rule patch | Values injected by a matching rule at runtime |
| System default | Fallback values from the LCARdS core |
When values conflict, higher-priority sources win (card config > rule > preset > default). Provenance shows you the winning value and which layer it came from.
Use this when a card isn't rendering as expected and you need to see what the effective config actually is.
Related
- DataSources — subscription config and processing pipeline reference
- Rules Engine — rule conditions, targets, and style patches
- Themes — token namespaces and colour palette
- Presets — how presets compose with card config