What a Local First Native Mac App Actually Looks Like on Disk

Three things have to be true at once. One, the binary is compiled for macOS (AppKit or SwiftUI, signed, notarized, distributed as a .app or .pkg), not an Electron window. Two, the app's primary read path is a file on your disk, not a request to a server. Three, writes succeed fully offline and sync is opt-in per record. Fazm satisfies all three: a Swift app signed by Mediar, a per-user SQLite database at ~/Library/Application Support/Fazm/users/{firebaseUid}/fazm.db, and a per-row backendSynced column that defaults to false.

~/Library/Application Support/Fazm/users/{firebaseUid}/fazm.db, with the SQLite WAL and SHM sidecar files next to it. The screenshot cache lives at ~/Library/Application Support/Fazm/Screenshots/. If the database ever fails quick_check, a backup is written to ~/Library/Application Support/Fazm/backups/omi_corrupted_{timestamp}.db and the recovery path tries a SQLite .recover dump. All of that logic lives in Desktop/Sources/AppDatabase.swift at lines 238 through 745.

Every read path does. File indexing, knowledge graph lookups, chat history search via the chat_messages_fts FTS5 virtual table, user profile, and settings all resolve from the local SQLite file. Chat inference calls a model provider over the network by default, but you can point Fazm at a local endpoint (Ollama, LM Studio) if you have one running. The data layer never needs the network to answer a query.

It means some tables have a backendSynced boolean column, others do not. ai_user_profiles, chat_messages, and task_chat_messages carry the flag, so individual rows can be pushed to the backend later. indexed_files, local_kg_nodes, local_kg_edges, and observer_activity do not carry the flag and never leave the disk. You can verify this in Desktop/Sources/AppDatabase.swift lines 880 through 990: look at which CREATE TABLE blocks include the t.column("backendSynced", .boolean) line and which do not.

WAL (write-ahead log) lets readers and writers proceed concurrently and survives most crashes without corrupting the main db file. Fazm sets journal_mode = WAL, synchronous = NORMAL, and wal_autocheckpoint = 1000 pages (roughly four megabytes) on open. See Desktop/Sources/AppDatabase.swift lines 388 through 392. If WAL fails (disk I/O error, read-only volume), the app falls back to the default journal mode and keeps going rather than refusing to launch.

An Electron app is a Chromium instance wrapping a web page. The data file is usually an IndexedDB directory or a JSON blob the web app serializes. It cannot read the macOS accessibility tree, cannot register a Carbon global hotkey, cannot register with SMAppService for launch-at-login, and does not get any macOS power-management notifications. Fazm is a native Swift binary. It uses AXUIElementCreateApplication to read the frontmost window, SMAppService.mainApp.register() to start at login, and NSWorkspace observers for sleep, wake, lock, and unlock. None of those are available to a web app in a window.

Yes. The full migrator lives in Desktop/Sources/AppDatabase.swift, and the repo is public at github.com/mediar-ai/fazm. If you want to audit the schema, open that one file and search for migrator.registerMigration. Five migrations so far: fazmV1 creates ai_user_profiles, indexed_files, local_kg_nodes, local_kg_edges. fazmV2 adds task_chat_messages. fazmV3 renames it to chat_messages. fazmV4 adds observer_activity. fazmV5 adds a session_id column and a chat_messages_fts FTS5 virtual table.

On every open, Fazm runs PRAGMA quick_check. If the result is anything other than ok, the file is moved to ~/Library/Application Support/Fazm/backups/omi_corrupted_{timestamp}.db, and the app tries to recover rows using the SQLite .recover command-line tool. If recovery succeeds, those rows are re-imported into a fresh db. If it fails, the app starts with a clean schema. No spinner, no modal, no call home. Source: Desktop/Sources/AppDatabase.swift lines 680 through 745.

No. Screen recording is only needed if you enable the optional screenshot cache for a specific workflow. The default context-extraction path uses the macOS Accessibility tree via AXUIElementCopyAttributeValue, which reads window titles, focused fields, and button roles without capturing pixels. Concretely: AppState.swift calls AXUIElementCreateApplication(pid) on the frontmost process, then copies kAXFocusedWindowAttribute. No Vision framework import, no OCR.

Yes. Quit the app, delete ~/Library/Application Support/Fazm/users/{firebaseUid}/, relaunch. Fazm will recreate the directory and run all five migrations fresh. Your chat history, file index, and knowledge graph are gone. Anything that had backendSynced = true at the time of last sync will re-download on next login; anything that was local-only is gone for good. That is the correct privacy trade: local-only means local-only.