Split BrainBar daemon and UI

[EtanHey]

Summary

• Adds a separate BrainBarDaemon SwiftPM executable that owns the BrainBar MCP socket, brain bus, single-writer server path, and hybrid helper lifecycle.
• Keeps BrainBar as the LSUIElement UI process with NSStatusItem/NSPopover from item test: QA integration tests + fix FTS5 query escaping #6 and a reconnecting BrainBusClient subscriber from item feat(engine): Think/Recall/Sessions intelligence layer #5.
• Updates build-app.sh to build both products, embed both binaries into BrainBar.app, and install two ProcessType=Interactive LaunchAgents.
• Aligns fresh Swift-created DBs with the Phase D Python helper by keeping schema_migrations.details present.
• Documents the two-process UDS topology in README.md.

30-second lecture demo

bash brain-bar/build-app.sh
launchctl print gui/$(id -u)/com.brainlayer.brainbar-daemon | head -40
launchctl print gui/$(id -u)/com.brainlayer.brainbar | head -40
pgrep -fl 'BrainBar|BrainBarDaemon'
kill -9 $(pgrep -x BrainBar)
python3 - <<'PY'
import json, socket
path = '/tmp/brainbar.sock'

def send(sock, payload):
    body = json.dumps(payload, separators=(',', ':')).encode()
    sock.sendall(f'Content-Length: {len(body)}\r\n\r\n'.encode() + body)

def recv(sock):
    data = b''
    while b'\r\n\r\n' not in data:
        data += sock.recv(1)
    header, body = data.split(b'\r\n\r\n', 1)
    length = int([line.split(':', 1)[1] for line in header.decode().split('\r\n') if line.lower().startswith('content-length:')][0])
    while len(body) < length:
        body += sock.recv(length - len(body))
    return json.loads(body[:length])

with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as sock:
    sock.connect(path)
    send(sock, {"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"lecture-demo","version":"1"}}})
    print(recv(sock).get('result', {}).get('serverInfo'))
PY
launchctl kickstart -k gui/$(id -u)/com.brainlayer.brainbar
sleep 2
pgrep -fl 'BrainBar|BrainBarDaemon'

Expected: killing BrainBar does not remove /tmp/brainbar.sock; the daemon still answers MCP; kickstarting the UI relaunches the menu-bar process.

Verification

• TDD red: swift test --package-path brain-bar --filter DatabaseTests/testSchemaMigrationsTableIncludesDetailsForHybridHelperParity failed before the Swift schema migration added details.
• pytest tests/test_brainbar_build_app_guards.py -q -> 13 passed.
• swift build --package-path brain-bar --product BrainBar -> passed.
• swift build --package-path brain-bar --product BrainBarDaemon -> passed.
• Isolated daemon smoke: launched BrainBarDaemon with temp BRAINBAR_SOCKET_PATH + BRAINBAR_DB_PATH; initialize succeeded and tools/list returned 16 tools over UDS.
• swift test --package-path brain-bar -> 363 passed.
• Pre-push gate -> pytest unit suite 2018 passed, 9 skipped, 75 deselected, 1 xfailed; MCP registration 3 passed; isolated eval/hook 32 passed; Bun 1 passed; FTS5 regression passed.

---

Note

Medium Risk
Splits BrainBar into two cooperating processes and updates launchd packaging/build scripts, which can impact startup/IPC reliability and deployment behavior. Also adjusts SQLite schema migration compatibility, which could affect fresh DB initialization if incorrect.

Overview
BrainBar is split into two SwiftPM executables: BrainBarDaemon now owns the MCP server and /tmp/brainbar.sock, while BrainBar becomes a UI-only menu bar shell that no longer starts/stops the server or requires database readiness for URL handling.

The build and install flow is updated to build/embed both binaries into BrainBar.app and install two ProcessType=Interactive LaunchAgents (com.brainlayer.brainbar + com.brainlayer.brainbar-daemon), with new tests and a new daemon LaunchAgent plist.

SQLite startup migrations are tweaked to ensure schema_migrations.details exists (and is backfilled via ALTER TABLE when missing) to maintain compatibility with the hybrid helper.

^{Reviewed by Cursor Bugbot for commit 983a1a3. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Split BrainBar into separate UI and headless BrainBarDaemon processes

• Introduces a new BrainBarDaemon executable (BrainBarDaemonMain.swift) that owns the MCP server, Unix domain socket (/tmp/brainbar.sock), SQLite DB, and helper process lifecycle, running as a persistent launchd agent via com.brainlayer.brainbar-daemon.plist.
• The BrainBar UI app (BrainBarApp.swift) no longer starts or manages the server, database, or InjectionStore; it assumes the daemon is already running.
• Package.swift declares both executables; build-app.sh builds, validates, and installs both binaries and their respective LaunchAgents.
• Shared source files are symlinked into Sources/BrainBarDaemon/ rather than duplicated.
• BrainDatabase.ensureChunkColumns now adds a details column to schema_migrations if absent.
• Behavioral Change: quick capture panel invocation in non-menu-bar-window mode now logs and returns instead of opening a panel; isReadyToHandleBrainBarURL always returns true.

📊 Macroscope summarized 983a1a3. 7 files reviewed, 2 issues evaluated, 0 issues filtered, 1 comment posted

🗂️ Filtered Issues

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[EtanHey]

@cursor review

Please review the BrainBar Swift split, especially AppDelegate runtime wiring, NSStatusItem/NSPopover continuity from item #6, and reconnect/no-poll assumptions from item #5.

[EtanHey]

@BugBot review

Please check for launchd lifecycle regressions, socket ownership/races, helper subprocess startup issues, and single-writer violations.

[EtanHey]

@codex review

Focus on the daemon/UI process boundary, launchd plist/install behavior, Phase D helper compatibility, and whether any UI path still starts an in-process server or writes directly.

[macroscopeapp]

🟢 Low brain-bar/build-app.sh:321

The success message "[build-app] LaunchAgents installed — daemon and UI restart independently" at line 328 prints unconditionally, even when neither $DAEMON_PLIST_SRC nor $UI_PLIST_SRC exists and no LaunchAgent was actually installed. Consider only printing the message when at least one plist file exists and install_launchagent was invoked.

🚀 Reply "fix it for me" or copy this AI Prompt for your agent:

In file brain-bar/build-app.sh around line 321:

The success message `"[build-app] LaunchAgents installed — daemon and UI restart independently"` at line 328 prints unconditionally, even when neither `$DAEMON_PLIST_SRC` nor `$UI_PLIST_SRC` exists and no LaunchAgent was actually installed. Consider only printing the message when at least one plist file exists and `install_launchagent` was invoked.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Stop opening the database from the UI collector

In the split UI process, this still constructs a StatsCollector, whose initializer creates a BrainDatabase(path:); that connection opens READWRITE | CREATE, runs PRAGMAs, and calls ensureMigrations() on startup. So every BrainBar UI launch can still acquire write locks and mutate schema directly instead of only watching the daemon/socket, which violates the new single-writer process boundary and can race the daemon on the canonical WAL DB.

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[chatgpt-codex-connector]

Restore a daemon-backed command bar model

With runtime.database permanently installed as nil, BrainBarWindowRootView never creates its QuickCaptureViewModel because commandBarProvider.viewModel(database:) only becomes ready for a non-nil database. In menuBarWindow mode, the Capture/Search menu commands and hotkey now only show the popover with the “Warming memory…” placeholder forever, so the UI quick-capture/search path is disabled unless it is replaced with a socket-backed model.

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[cursor]

Cursor Bugbot has reviewed your changes and found 3 potential issues.

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[cursor]

UI dashboard permanently stuck in degraded state

High Severity

makeUIStatsCollector passes targetPID: 0 to DaemonHealthMonitor. Since DaemonHealthMonitor.sample() has a guard targetPID > 0 else { return nil } check, it always returns nil. This causes PipelineState.derive(daemon: nil, ...) to always evaluate as .degraded, and DashboardFlowSummary to always show "Pipeline visibility is degraded" with all pipeline indicators as .unavailable — regardless of actual daemon health.

Additional Locations (1)

• brain-bar/Sources/BrainBar/BrainBarApp.swift#L96-L99

 

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[cursor]

UI process writes to database violating single-writer design

Medium Severity

The UI process's StatsCollector creates a BrainDatabase(path: dbPath) that calls openAndConfigure() → ensureMigrations(), which executes DDL statements (CREATE VIEW IF NOT EXISTS, ALTER TABLE ADD COLUMN, etc.) against the same database the daemon owns. This violates the single-writer architecture the PR establishes, where BrainBarDaemon is documented as owning "the single-writer path."

 

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[cursor]

Stale log message claims socket ownership the UI lacks

Low Severity

The log message "Socket ready; database will self-heal" is a leftover from the pre-split code. The UI process no longer owns a socket or database — the daemon does. This makes diagnostic logs actively misleading during incident response.

 

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