Lumotia/docs/architecture-map/02-tauri-runtime

name, type, slice, last_verified

name	type	slice	last_verified
Slice 02 — Tauri runtime	architecture-map-page	02-tauri-runtime	2026/05/12

Slice 02 — Tauri runtime

Where you are: Architecture map → Tauri runtime

Plain English summary. The Tauri runtime is the bridge between Lumotia's Svelte frontend and the Rust workspace crates. It owns app startup (database init, panic hook, plugin wiring, preferences injection), the system tray, the secondary windows (task float, transcript viewer, transcription preview), and the entire #[tauri::command] surface that the frontend invokes for audio capture, transcription, LLM cleanup, task and transcript CRUD, paste, TTS, hotkeys, diagnostics, and more. Everything that runs on the host process but is not pure crate logic lives here.

At a glance

• Path: src-tauri/
• Total LOC (Rust + Cargo + JSON, excluding gen/): ~8,690.
• Tauri version: 2 (see src-tauri/Cargo.toml:44).
• Bundle identifier: uk.co.corbel.lumotia (src-tauri/tauri.conf.json:5).
• Plugins (always-on): tauri-plugin-opener, tauri-plugin-dialog, tauri-plugin-notification.
• Plugins (desktop-only, gated cfg(not(target_os = "android"))): tauri-plugin-global-shortcut, tauri-plugin-autostart (LaunchAgent), tauri-plugin-window-state. The tray-icon Tauri feature is also desktop-only.
• Workspace crates pulled in: lumotia-core, lumotia-audio, lumotia-transcription (default-features off, whisper re-enabled here), lumotia-ai-formatting, lumotia-storage, lumotia-cloud-providers, lumotia-hotkey, lumotia-llm.
• Tauri commands exposed via invoke_handler in src-tauri/src/lib.rs:321: 71 commands.
• Capability files: src-tauri/capabilities/main.json (main window) and src-tauri/capabilities/secondary-windows.json (task float, transcript viewer, transcription preview).
• Command modules: 22 #[tauri::command] modules plus 3 utility modules (mod.rs, power.rs, security.rs).
• Integration tests: src-tauri/tests/config_hardening.rs (3 tests guarding CSP, updater signing, secondary-window permissions).

Map of this slice

App boot, config, tests:

• App lifecycle. src-tauri/src/main.rs and src-tauri/src/lib.rs. Run entry, AppState construction, plugin wiring, preferences injection, Linux launcher-env warning, panic hook, error-log pruning, command registration.
• System tray. Desktop-only tray icon and menu (src-tauri/src/tray.rs).
• Tauri config. tauri.conf.json plus the Linux native-decorations overlay; CSP, window defaults, bundle settings.
• Capabilities and ACL. The two ACL files in capabilities/, what each scopes, and the Phase 9 high-risk-permission firewall.
• Cargo and features. Cargo.toml, the whisper cargo feature, the per-target dependency blocks, build.rs, .cargo/config.toml.
• Tests. Config-hardening regression tests.

Command modules (entry index):

• Commands index. Every command file with a one-liner.

Individual command pages (linked from the commands index):

• Audio capture, Live transcription, Paste at cursor, Models registry and runtime, Transcription, Local LLM, Text to speech, Tasks and decomposition, Transcripts CRUD, Diagnostics and reports, Implementation intentions, Profiles, Window management, Hotkey bridge, Feedback capture, Power assertions and security, Small commands, mod.rs registration.

How this slice connects to others

• Frontend (slice 01). Every #[tauri::command] is invoked from Svelte via @tauri-apps/api/core invoke(). Events emitted via app.emit(...) are consumed via listen() in the frontend. Live transcription uses typed tauri::ipc::Channel instead of plain events; the channel pair is created on the JS side and passed in as command args.
• Audio + transcription (slice 03). commands::audio calls lumotia_audio::{MicrophoneCapture, WavWriter, decode_audio_file_limited, resample_to_16khz, probe_audio_duration_secs}. commands::transcription and commands::live call lumotia_transcription::LocalEngine plus lumotia_audio::StreamingResampler. commands::models calls lumotia_transcription::{model_manager, load_whisper, load_parakeet}.
• LLM + formatting + MCP (slice 04). commands::llm calls lumotia_llm::{LlmEngine, model_manager, ContentTags, LlmModelId} and lumotia_ai_formatting::{llm_cleanup_text, LlmPromptPreset}. commands::tasks calls lumotia_llm::prompts::FeedbackExample and the engine's decompose_task_with_feedback / extract_tasks_with_feedback / extract_content_tags. commands::transcription and commands::live call lumotia_ai_formatting::{post_process_segments, FormatMode, PostProcessOptions}. commands::profiles calls lumotia_ai_formatting::extract_corrections for auto-learned vocabulary.
• Core + storage + hotkey + build (slice 05). Everything DB-touching goes through lumotia_storage (init, database_path, get_setting, set_setting, prune_error_log, the full set of CRUD helpers, app_data_dir, crashes_dir, logs_dir, list_recent_errors, log_error). commands::hardware and commands::models call lumotia_core::{hardware, model_registry, recommendation, types, constants}. commands::meeting calls lumotia_core::process_watch. commands::hotkey is a thin Tauri wrapper around lumotia_hotkey::{EvdevHotkeyListener, HotkeyCombo, HotkeyEvent}. build.rs is the build-system half of the slice (CSP regression guard plus ggml multi-definition link arg).

Open questions / debt

• commands/live.rs is 1,737 LOC. The runtime, loop state, speech gate, dedup, and chunking logic share the file. Splitting per concern would track against the broader refactor pass already mooted in the in-repo code review (docs/code-review-2026-04-22.md). See commands/live.md for the breakdown.
• commands::update::install_update returns a hard-coded "Updates are disabled until release signing is configured." (src-tauri/src/commands/update.rs:15). The integration test updater_is_signed_or_absent (src-tauri/tests/config_hardening.rs:35) only asserts that if an updater config ships, it carries a non-empty pubkey. There is currently no updater config in tauri.conf.json, so the test is an empty no-op.
• commands::power::PowerAssertion is a no-op on Linux and Windows (src-tauri/src/commands/power.rs:90). Only macOS has a real implementation via objc2. The doc comment promises SetThreadExecutionState (Windows) and logind inhibitors (Linux), but neither is wired up. Symptom: long live-dictation sessions on Linux can be idled by the compositor.
• src-tauri/.cargo/config.toml hard-codes LIBCLANG_PATH = "C:\\Program Files\\LLVM\\bin" (Windows). It is harmless on non-Windows hosts (env var is just unused) but it is a foot-gun if someone moves Clang elsewhere on Windows. See Cargo and features.
• The Linux rendering workaround in lib.rs (warn_if_x11_env_unset_on_wayland) now warns when the launcher has not set the expected env vars; it no longer mutates the process environment. In development, run.sh / npm run dev:tauri owns the defaults (WEBKIT_DISABLE_DMABUF_RENDERER=1 on Linux; GDK_BACKEND=x11 and WINIT_UNIX_BACKEND=x11 on Wayland). The user opt-out remains WEBKIT_DISABLE_DMABUF_RENDERER=0, set before launching.
• commands::diagnostics::install_panic_hook writes a "minimal text dump" without backtraces unless the user has RUST_BACKTRACE=1 set (src-tauri/src/commands/diagnostics.rs:42). The packaged binary does not set it, so production crash dumps will lack stack traces. Document or default-enable.
• commands::audio::list_audio_devices is gated ensure_main_window but the secondary-windows capability does not invoke it, which is correct. The clipboard::copy_to_clipboard command, by contrast, has no main-window guard and any window with the core:default permission can call it; intentional, but worth flagging.

Existing in-repo docs

• docs/code-review-2026-04-22.md. The MAJOR / MINOR review that motivated several of the safety helpers seen here (the parallel-mode loopback CSP guard in build.rs, secondary-window high-risk-permission test, RB-06 worker-join in commands::audio, RB-07 compose_accelerators in commands::models, RB-08 macOS App Nap power assertion in commands::power).
• docs/issues/. Open issue threads, several of which the diagnostic-report bundler exists to feed.
• docs/whisper-ecosystem/brief.md. Source of the numbered "brief items" cited in code comments (item #2 = loopback LLM CSP, item #9 = App Nap, items #10/#17 = paste / replace flows, item #19 = progressive WAV writer, item #28 = sequential-GPU mode).
• docs/handovers/. Daily handover docs that cite specific command surfaces; useful when the in-source comments cite a "RB-NN review point".
• docs/dev-setup.md. Linux + Windows + macOS toolchain setup, including the Vulkan loader install required for GPU-backed whisper.cpp.