---
name: Frontend ↔ Tauri bridge
type: architecture-map-page
slice: 01-frontend
last_verified: 2026/05/09
---

# Frontend ↔ Tauri bridge

> **Where you are:** [Architecture map](../README.md) → [Frontend](README.md) → Frontend ↔ Tauri bridge

**Plain English summary.** The complete surface where the Svelte frontend talks to the Rust runtime. Two channels: synchronous request/response via `invoke()`, and asynchronous events via `listen()` / `emit()`. Every command name and every event name the frontend touches is listed here so slice 02 can verify reciprocal mentions.

## At a glance

- **Direction in (Rust → frontend):** events listed under "Tauri events listened to".
- **Direction out (frontend → Rust):** all `invoke()` commands listed under "Tauri commands invoked".
- **DOM-only events:** `lumotia:*` `CustomEvent`s on `window`. These never cross the Rust boundary.
- **Cross-window event:** `lumotia:preferences-changed` is the only one that goes through `emit()`.

## Tauri commands invoked (alphabetical)

Discovered via `grep -rho 'invoke([\"\\']\\([a-zA-Z_][a-zA-Z0-9_]*\\)' src/`. Each name appears at least once in the frontend.

| Command | Caller(s) |
|---|---|
| `add_transcript` | `stores/page.svelte.ts:234` (`addToHistory`) |
| `check_engine` | `pages/SettingsPage.svelte:826` |
| `check_for_update` | `routes/+layout.svelte:356` |
| `check_hotkey_access` | `routes/+layout.svelte:86` |
| `check_llm_model` | `pages/DictationPage.svelte:241`, `pages/SettingsPage.svelte:597` |
| `check_parakeet_engine` | `pages/SettingsPage.svelte:857` |
| `check_parakeet_model` | `pages/SettingsPage.svelte:858` |
| `cleanup_transcript_text_cmd` | `pages/DictationPage.svelte:472` |
| `complete_task_cmd` | `stores/page.svelte.ts:474` |
| `copy_to_clipboard` | DictationPage, FilesPage, HistoryPage, viewer/+page, preview/+page |
| `delete_implementation_rule` | `stores/implementationIntentions.svelte.ts:82` |
| `delete_llm_model` | `pages/SettingsPage.svelte:660` |
| `delete_profile_cmd` | `stores/profiles.svelte.ts:93` |
| `delete_profile_term_cmd` | `stores/profiles.svelte.ts:121` |
| `delete_task_cmd` | `stores/page.svelte.ts:456` |
| `delete_transcript` | `stores/page.svelte.ts:320`, `pages/HistoryPage.svelte:285` |
| `deliver_nudge` | `stores/nudgeBus.svelte.ts:112` |
| `detect_meeting_processes` | `routes/+layout.svelte:399` |
| `detect_paste_backends` | `pages/SettingsPage.svelte:850` |
| `download_llm_model` | `pages/SettingsPage.svelte:619` |
| `download_model` | `pages/SettingsPage.svelte:929`, `pages/FirstRunPage.svelte:59` |
| `download_parakeet_model` | `pages/SettingsPage.svelte:988`, `pages/FirstRunPage.svelte:73` |
| `extract_content_tags_cmd` | `pages/HistoryPage.svelte:433, 470` |
| `extract_tasks_from_transcript_cmd` | `pages/DictationPage.svelte:491` |
| `generate_diagnostic_report` | `pages/SettingsPage.svelte:377` |
| `get_llm_status` | DictationPage, SettingsPage, layout (refresh path) |
| `get_runtime_capabilities` | `pages/DictationPage.svelte:134`, `pages/SettingsPage.svelte:543` |
| `is_wayland_session` | `routes/+layout.svelte:82` |
| `list_audio_devices` | `pages/SettingsPage.svelte:187` |
| `list_models` | `routes/+layout.svelte:346`, `pages/SettingsPage.svelte:846, 930` |
| `list_parakeet_models` | `routes/+layout.svelte:347` |
| `load_llm_model` | `pages/DictationPage.svelte:243`, `pages/SettingsPage.svelte:634` |
| `load_model` | `pages/DictationPage.svelte:272`, `pages/SettingsPage.svelte:944`, `pages/FirstRunPage.svelte:60` |
| `load_parakeet_model` | `pages/DictationPage.svelte:270`, `pages/SettingsPage.svelte:1003`, `pages/FirstRunPage.svelte:74` |
| `log_frontend_error` | `routes/+layout.svelte:282` |
| `open_preview_window` | `pages/DictationPage.svelte:385` |
| `open_task_window` | `pages/TasksPage.svelte:231` |
| `open_viewer_window` | `pages/HistoryPage.svelte:392, 556` |
| `paste_text` | `pages/DictationPage.svelte:544` |
| `paste_text_replacing` | `routes/preview/+page.svelte:92` |
| `prewarm_default_model_cmd` | `routes/+layout.svelte:371` |
| `probe_system` | `pages/SettingsPage.svelte:822`, `pages/FirstRunPage.svelte:31` |
| `rank_models` | `pages/FirstRunPage.svelte:32` |
| `recommend_llm_tier` | `pages/SettingsPage.svelte:587` |
| `save_diagnostic_report` | `pages/SettingsPage.svelte:405` |
| `save_preferences` | `stores/preferences.svelte.ts:109` |
| `start_evdev_hotkey` | `routes/+layout.svelte:129` |
| `start_live_transcription_session` | `pages/DictationPage.svelte:344` |
| `stop_evdev_hotkey` | `routes/+layout.svelte:424` |
| `stop_live_transcription_session` | `pages/DictationPage.svelte:415` |
| `test_llm_model` | `pages/SettingsPage.svelte:684` |
| `transcribe_file` | `pages/FilesPage.svelte:76` |
| `tts_list_voices` | `pages/SettingsPage.svelte:750` |
| `tts_speak` | `pages/SettingsPage.svelte:769`, `stores/implementationIntentions.svelte.ts:170`, `stores/nudgeBus.svelte.ts:119` |
| `tts_stop` | `components/SpeakerButton.svelte` (cancel current TTS) |
| `uncomplete_task_cmd` | `stores/page.svelte.ts:491` |
| `unload_llm_model` | `pages/SettingsPage.svelte:648` |
| `update_evdev_hotkey` | `routes/+layout.svelte:127` |
| `update_profile_cmd` | `stores/profiles.svelte.ts:77` |
| `update_transcript` | `stores/page.svelte.ts:272`, `routes/viewer/+page.svelte:326` |

Plus any commands invoked by `saveMarkdown.ts` via the dialog/file-write plugin imports rather than direct `invoke`. (Verified the truncated `tts_s...` resolves to `tts_speak` and `tts_stop`; both are listed.)

## Tauri events listened to (Rust → frontend)

| Event | Listener |
|---|---|
| `lumotia:hotkey-pressed` | `routes/+layout.svelte:177` (evdev backend) |
| `lumotia:llm-download-progress` | `pages/SettingsPage.svelte:873` |
| `lumotia:open-wind-down` | `routes/+layout.svelte:251` (tray menu hook) |
| `lumotia:preferences-changed` | `routes/+layout.svelte:263`, `routes/float/+layout@.svelte`, `routes/viewer/+layout@.svelte`, `routes/preview/+layout@.svelte:41` |
| `model-download-progress` | `pages/SettingsPage.svelte:864`, `pages/FirstRunPage.svelte:46`, `components/ModelDownloader.svelte:31` |
| `parakeet-download-progress` | `pages/SettingsPage.svelte:880`, `pages/FirstRunPage.svelte:50` |
| `preview-cleanup` | `routes/preview/+page.svelte:141` |
| `preview-hide` | `routes/preview/+page.svelte:161` |
| `preview-listening` | `routes/preview/+page.svelte:113` |
| `task-window-focus` | `routes/float/+layout@.svelte` |
| `tauri://drag-drop` | `pages/FilesPage.svelte:28` |
| `tauri://drag-enter` | `pages/FilesPage.svelte:34` |
| `tauri://drag-leave` | `pages/FilesPage.svelte:35` |

## Tauri events emitted (frontend → Rust or other windows)

| Event | Emitter | Purpose |
|---|---|---|
| `lumotia:preferences-changed` | `stores/preferences.svelte.ts` (`broadcastPreferences`) | Cross-window preference sync. |
| `preview-append` | `pages/DictationPage.svelte:165` | Stream partial text to overlay window. |
| `preview-listening` | `pages/DictationPage.svelte:381` | Tell overlay to enter listening state. |
| `preview-cleanup` | `pages/DictationPage.svelte:531` | Tell overlay to enter cleanup state. |
| `preview-final` | `pages/DictationPage.svelte:539` | Tell overlay to render final text. |
| `preview-hide` | `pages/DictationPage.svelte:606` | Tell overlay to dismiss. |

## DOM-only `lumotia:*` window events (intra-frontend bus)

| Event | Dispatcher | Listener(s) |
|---|---|---|
| `lumotia:focus-timer-cancelled` | `stores/focusTimer.svelte.ts` | `completionStats` (indirectly), components subscribed to focus timer. |
| `lumotia:focus-timer-complete` | `stores/focusTimer.svelte.ts` | Same as above. |
| `lumotia:implementation-rules-changed` | `stores/implementationIntentions.svelte.ts` | `ImplementationRulesEditor`. |
| `lumotia:microstep-generated` | `stores/nudgeBus.svelte.ts` (around micro step generation) | `MicroSteps.svelte`. |
| `lumotia:morning-triage-finished` | `MorningTriageModal.svelte` | `nudgeBus`. |
| `lumotia:start-timer` | `WipTaskList.svelte`, `MicroSteps.svelte` | `FocusTimer.svelte` + `focusTimer` store. |
| `lumotia:step-completed` | `MicroSteps.svelte` | `completionStats` refresh. |
| `lumotia:task-completed` | `stores/page.svelte.ts` (`completeTask`) | `completionStats`. |
| `lumotia:task-deleted` | `stores/page.svelte.ts` (`deleteTask`) | `completionStats`. |
| `lumotia:task-uncompleted` | `stores/page.svelte.ts` (`uncompleteTask`) | `completionStats`. |
| `lumotia:toggle-recording` | `routes/+layout.svelte` (after hotkey debounce, both backends) | `pages/DictationPage.svelte`. |

## Window APIs

- `getCurrentWindow().minimize()` and `.toggleMaximize()`. `Titlebar.svelte`.
- `getCurrentWindow().label`. Used to guard hotkey registration to the main window only and to filter own-source preference echoes.
- `convertFileSrc(absolutePath)`. HistoryPage and viewer use this for `<audio>` elements.

## Plugins

| Plugin | Used by |
|---|---|
| `@tauri-apps/plugin-dialog` | `utils/saveMarkdown.ts`, `pages/FilesPage.svelte:handleBrowse`. |
| `@tauri-apps/plugin-global-shortcut` | `routes/+layout.svelte` (X11 / macOS / Windows hotkey backend). |
| `@tauri-apps/plugin-autostart` | SettingsPage launch-at-login toggle. |
| `@tauri-apps/plugin-notification` | Available, used by nudge bus or a related path. Confirm specific call sites. |
| `@tauri-apps/plugin-opener` | Available, used to open external URLs. Confirm specific call sites. |

## Watch outs

- The truncated grep returned `tts_s...` as a unique prefix. Verify every TTS command name (`tts_speak`, possibly `tts_stop`) against `lib.rs` to make sure the table above is exhaustive.
- The "preview-*" events have two flavours: `lumotia:` namespaced (`preferences-changed`) and bare (`preview-listening`, `preview-cleanup`, `preview-hide`, `preview-append`, `preview-final`). The bare names are scoped to the overlay window's two-way handshake. Do not rename.
- `lumotia:open-wind-down` listener is in `+layout.svelte` so the page opens regardless of which window the tray click came from. If you ever isolate windows further, this assumption breaks.
- `task-window-focus` is the only event sent specifically to the float window.
- DOM `CustomEvent` handlers do not survive across windows (they are window-local). The tasks list refresh trick on focus relies on this.

## See also

- [Windows and routes](windows-and-routes.md). For the listener mounting points.
- [Stores](stores.md). For the dispatch points of intra-frontend events.
- [../02-tauri-runtime/README.md](../02-tauri-runtime/README.md). For the matching Rust handlers (slice 02 will mirror this table from the other side).
