tinycast/AGENTS.md

Project

Tinycast is a native macOS menu-bar launcher (a minimal Raycast): fuzzy app launcher, global + per-app hotkeys, a text/image clipboard history, an inline calculator, and an emoji picker. SwiftUI + AppKit, runs as an accessory (no Dock icon, LSUIElement). Targets macOS 26+ (Liquid Glass) and builds with the Xcode 26 toolchain.

• Build: XcodeGen owns the project — Tinycast.xcodeproj is committed but generated from project.yml. After editing project.yml, run xcodegen generate and commit. There is no Package.swift / SwiftPM. Full build/test/sign/release steps: docs/development.md, docs/signing.md.
• Channels: Debug builds are their own channel — Tinycast Dev.app / com.tinycast.app.dev — so a local run never shares prefs, caches, TCC grants or login item with an installed stable/beta. Anything newly persisted must stay keyed by Bundle.main.bundleIdentifier.
• Tests: no XCTest target — standalone swiftc harnesses in Tools/ (see Critical Invariants and docs/development.md).

Project Philosophy

General engineering principles — simple over clever, declarative views, Swift 6 isolation, remove dead code — come from the global CLAUDE.md and are not repeated here. Tinycast adds one rule of its own:

Comments — minimal code, not annotated prose

1. One line. Never two consecutive comment lines. If it needs two, it needs a named function, a named constant, or a type.
2. Hard cap: 100 characters, including indentation. Longer belongs in docs/<subsystem>.md.
3. Comment the why, the gotcha, or the invariant. Never restate the code, never narrate a sequence, never argue a decision at length in-line.
4. /// on a public type or method is exempt from rule 1, not from rule 2.
5. Prefer deleting a comment to updating it.
6. Never add a comment explaining a change you just made. The diff is not the audience.

Rules 1 and 2 are checkable, and both must come back 0:

find Tinycast -name "*.swift" ! -name "*.generated.swift" -exec \
  awk '/^[[:space:]]*\/\//{r++; if(r==2) b++; next} {r=0} END{print b+0}' {} \; | awk '{s+=$1} END {print s}'
grep -rhE '^\s*(//|///)' Tinycast --include="*.swift" | awk 'length>100' | wc -l

DesignSystem/Scrolling/EdgeDissolve.swift and ThinScrollbar.swift are the only exemptions, because they are off-limits entirely.

Architecture

Full detail: docs/architecture.md.

• Single-owner core. AppCore.shared (App/AppCore.swift) is a @MainActor singleton owning every long-lived manager and the window controllers. AppDelegate.applicationDidFinishLaunching calls AppCore.shared.start() and nothing else — that is the one wiring point. Palette / paste / launch actions are methods on AppCore that views call.
• Mostly AppKit windows. TinycastApp (@main) declares only a MenuBarExtra scene. The command palette is a borderless floating NSPanel hosting SwiftUI; Settings/About are plain NSWindows via AuxWindowController. SwiftUI Settings / Window scenes are deliberately avoided (unreliable for accessory apps).
• Subsystems: palette · launcher & fuzzy match · calculator · clipboard · emoji · snippets · quicklinks · window management · hotkeys · uninstall · Raycast import · UI & design system.

Critical Invariants

Never break these without an explicit task to do so.

• AppCore is the sole owner. New long-lived state belongs on AppCore, wired in start(); don't create competing singletons or wire managers elsewhere.
• PaletteWindowController solely owns the palette frame. The hosting view sets sizingOptions = [] so SwiftUI never drives the window size — otherwise the top edge drifts on the compact↔expanded swap.
• The app is locked to .darkAqua globally. The Liquid Glass material is tuned for a dark surface only; do not add light-mode styling.
• The flat selection index must match the visible row order exactly, including the inline calculator card at index 0 when present. Selection is the single source of truth for highlight / activation. Features/PaletteRowIndex.swift is that mapping, and it stays Foundation-only and pure — no SwiftUI, no AppKit — so Tools/palette-selection-test.swift compiles the shipped type rather than a copy. Section headers are not selectable and never consume an index.
• AppEntry.Kind is the only thing that says what an entry is. One case per launcher section, per VisibilityStore category and per Settings pane — never re-derive a category by sniffing an entry ID (that's what isCustomCommand used to do). A new category means a new case, a slice in AppIndex.publishEntries(), and the matching filter in LauncherList.rows, in that same order.
• While a footer menu is open the palette search field never resigns first responder — input is frozen instead (resigning shifts the text a point or two). See palette.md.
• Focus restoration is load-bearing. Paste targets the recorded previousApp and requires the Accessibility permission (Permissions.ensureAccessibility()). See palette.md.
• Features/Calculator/Model/ (incl. CalcDateTime) must stay Foundation-only and pure — no AppKit / SwiftUI imports, no clock or network reads. Tools/calc-test.swift compiles the real engine sources. Both externally-sourced inputs are injected: the clock via now/calendar, the FX table via rates (CurrencyRateStore owns the fetch). Likewise Features/Emoji/Model/ (EmojiCatalog, EmojiGridGeometry) stays AppKit/SwiftUI-free for Tools/emoji-test.swift, and Features/Clipboard/Model/ClipboardStore.swift must keep to Foundation + SQLite3 with no other app source, so Tools/clipboard-test.swift can compile it standalone. Launcher/Model/LauncherRankingStore.swift is the same deal for Tools/ranking-test.swift — Foundation only, with the clock injected via now and the store path via fileURL, as is Launcher/Model/SearchScopes.swift for Tools/scopes-test.swift. CustomCommands/Model/CustomCommand.swift and CustomCommands/Service/ShellCommandRunner.swift must stay free of AppKit / SwiftUI (Foundation plus Darwin for mkstemp) so Tools/custom-command-test.swift can compile them standalone — which is why the custom-command confirmation gate lives in AppCore and not in the runner. All of Features/Snippets/Model/ and Service/ compiles into Tools/snippets-test.swift (it globs both), so the model, Markdown serializer, template engine, repository and keyword policies stay Foundation-only, and the AppKit files there keep their dependencies to what the harness can stub. SystemActions/Model/SystemAction.swift is also Foundation-only for Tools/system-action-test.swift; platform effects belong in SystemActionRunner, while confirmation and failure UI remain in AppCore. SystemActions/Model/VolumeLevel.swift is the same split for Tools/volume-test.swift — the 5% step grid and the percentage string are pure Foundation, CoreAudio lives in SystemActionRunner and observation in VolumeState, so both the HUD and the Set Volume slider walk one tested grid. Features/WindowManagement/ splits the same way for Tools/window-command-test.swift: WindowCommand.swift, WindowLayout.swift and WindowActionMemory.swift stay Foundation + CoreGraphics and pure (no AX, no NSScreen, no clock — WindowActionMemory takes now as a parameter), while every AXUIElement call and the Cocoa↔AX coordinate flip live in WindowMover.swift.
• WindowLayout works exclusively in AX space — global coordinates, top-left origin, +Y down. WindowMover.AXGeometry is the only place that converts, and it anchors the flip on the primary display's height, never the window's own screen: doing otherwise shears every rect on a differently-sized display by the height difference, which is invisible on one monitor and wrong on every mixed-size setup. The visible consequence is that "Top Half" has minY == visibleFrame.minY; Tools/window-command-test.swift asserts it. Nothing in this feature ever touches backingScaleFactor — all three of NSScreen.frame, visibleFrame and AX coordinates are in points, so mixed-DPI correctness is automatic. See window-management.md.
• Uninstall moves to the Trash and never deletes. FileManager.trashItem is the only removal call in the feature; removeItem must never appear there. That is what makes display-name attribution tolerable — a false positive costs a drag back, not the user's data — so a "delete permanently" option would have to drop name matching in the same commit. The deciding half (UninstallTarget.swift, UninstallSearchRoot.swift, UninstallRules.swift, UninstallProtection.swift, UninstallPlan.swift) stays Foundation-only and pure for Tools/uninstall-test.swift, with every environment fact injected: the scanner hands the rules directory names, never URLs, and hands the classifier a PathFacts. Every FileManager, lstat and Full Disk Access read lives in UninstallScanner, which detects FDA (a silent, promptless probe) and never requests it — this feature asks for no permission and never escalates privilege. tccRelativePrefixes is measured, not assumed: probe a location by creating and trashing a throwaway directory there before adding it, because listing is not the test — ~/Library/Containers enumerates fine and still refuses the move, while ~/Library/Application Scripts allows it. A locked candidate can never enter the checked set; that invariant lives in UninstallSelection's one intersection, not in the view. Tinycast also refuses to plan its own uninstall, compared against the running identity so the Dev channel refuses itself too. See uninstall.md.
• Quicklinks are authored data, and their store never deletes. Quicklinks/Model/ splits like Uninstall/Model/: Quicklink.swift, QuicklinkDestination.swift, QuicklinkStore.swift and QuicklinkArchive.swift stay Foundation-only (plus SQLite3) and pure for Tools/quicklink-test.swift — the home directory is injected, never read — while QuicklinkLauncher owns every NSWorkspace call and QuicklinkArgumentSession the prompt state. The database lives in Application Support, not Caches, and a database that won't open is reported, never discarded: ClipboardStore's delete-and-recreate is only sound because history is regenerable, and a link library is not. Quicklink.precedes is the one display order, sorted through by both the store and the AppIndex slice. There is one template engine: quicklinks expand through SnippetTemplateEngine rather than a second parser, which is what makes | raw mean something — it opts a value out of the automatic percent-encoding a URL destination asks for. {selectedText} is accepted as an alias for {selection}, but nothing ever writes it. See quicklinks.md.
• Launcher/Model/SearchRelevance.swift is Foundation-only and pure, so Tools/fuzz-test.swift compiles the shipped scorer rather than a copy of it. It owns both FuzzyMatch (the tiered exact/prefix/word-start/substring/subsequence scorer) and the field bands. Searchable fields stay separate — display name, Spotlight alternate names, bundle id, executable name are never flattened into one string, because the field is what picks the band. Bands are one bandStride apart, an order of magnitude above FuzzyMatch.maximumScore and two above LauncherRankingStore's boost cap: that gap is what keeps a learned boost reordering within a tier and never across a tier or a field. A new searchable field means a new Band case and a consider call, in priority order.
• EmojiData.generated.swift is emitted by node Tools/gen-emoji.js and CurrencyData.generated.swift by node Tools/gen-currencies.js — never edit either by hand. Currency names, signs and uncontested nouns are generated (Frankfurter × CLDR); the only hand-maintained currency data is CalcCurrency.contested, the nouns several currencies share (dollars, pounds). Don't add slang or synonyms there — no source of truth, so they rot.
• Every networked feature ships off and is consent-gated. Tinycast is offline by default; a feature that reaches the network must be opt-in behind a Settings toggle whose dialog names the provider, the cadence and what leaves the machine, and its owning store must re-check consent at every entry point — including on both sides of the await around the request, since consent can be withdrawn mid-flight. Consent flags live on the owning store, never in AppSettings (SettingsBackup mirrors that type, and an import must not grant network access). Model the gate so the safe state is the default: CalcEngine.evaluate's currency: parameter defaults to .off, so forgetting to pass one disables the feature rather than enabling it. Fetch on a private cacheless URLSession (.ephemeral, urlCache = nil), never URLSession.shared — a cacheable response would leave a second copy in the on-disk URLCache that opting out doesn't delete. CurrencyRateStore is the reference implementation — follow it rather than inventing a second shape.
• SettingsBackup's mirror is hand-written, and reflection is never the fix. AppSettingsKey owns every key AppSettings persists; SettingsBackupCoverage says which of them SettingsData carries and which are excluded — today only snippetsEnabled, whose omission is a security control, since it doubles as keystroke-listening consent. A Mirror, macro or codegen scheme would auto-include the next consent flag and make it backup-restorable, so Tools/settings-backup-test.swift fails instead when a key is neither carried nor excluded with a reason. Adding a setting means editing SettingsBackupCoverage in the same commit. CurrencyRateStore's flag stays outside both by design.
• Snippets are channel-isolated and path-identified. Persist them under ~/Library/Application Support/<bundle-id>/Snippets/; StoredSnippet.ID is the standardized source path, and external rename is delete + create. The feature ships off and its enable switch doubles as keyword-expansion consent: snippetsEnabled is excluded from settings backups, and Accessibility — the only permission, since the listen-only tap needs nothing more — may be requested only from that explicit Settings gesture, never from startup, callbacks, watchers or health checks. See snippets.md.
• The two Raycast export formats share no mapper. RaycastFormat.detect is the only branch between them; RaycastImportV1 and RaycastImportV2 own their own decrypt and their own field mapping, and neither is ever tried as a fallback for the other (that is what makes a wrong passphrase report a wrong passphrase instead of "not a Raycast export"). They meet only at RaycastImport.Result. RaycastFormat.swift and RaycastV1Decoder.swift stay Foundation + CommonCrypto + Carbon so Tools/raycast-test.swift compiles them standalone, which is why the decoder returns Raycast's own values and RaycastImportV1 — not the decoder — validates them against PopToRootTimeout / EmojiSkinTone / HyperKeyPhysicalKey / KeyShortcut. Never commit a real .rayconfig as a fixture: the harness builds its own. See raycast-import.md.
• Swift 6 language mode: data-race violations are hard errors. Almost everything is @MainActor; cross-actor model types are Sendable; heavy / IO work (app scan, image decode) is pushed off-main via Task.detached / nonisolated. Keep that boundary. House idioms: NotificationToken (RAII) for block observers, isolated deinit for ClipboardStore's SQLite teardown, decode raw Carbon / C pointers to plain values before crossing into actor code.
• Clipboard writes stamp a private internalType marker so the poller skips Tinycast's own writes.
• Hotkeys persist as JSON strings under hotkey.<action> UserDefaults keys, and HotKeyAction.defaultsKey is the one place that computes a key — it is also the HotKeyCenter registration id, so the two can never drift. HotKeyBinding is the one thing an action is bound to and it has two cases with two engines: a .combo is a Carbon registration, a .doubleTap is recognized by DoubleTapMonitor (Carbon cannot see a lone modifier at all). Its Codable is the synthesised one; KeyShortcut's hand-written init(from:) is not a format seam but a correctness one, routing every decode through the initializer that masks device modifier bits off. LegacyHotKeyRecords adopts the shipped KeyboardShortcuts_ records once and is scheduled for deletion — see POLICY.md; nothing new may depend on it. HotKeys/Model/DoubleTapModifier.swift and DoubleTapDetector.swift stay Foundation-only and pure with the clock injected as a parameter, for Tools/hotkey-test.swift; every CGEvent call lives in DoubleTapMonitor.swift, which is listen-only, installs only while something is bound to a double-tap, and never prompts for Accessibility. See hotkeys.md.
• Tinycast presents its own dialogs, never NSAlert / NSSlider / system popovers. Every confirmation, failure report and value prompt goes through DialogController (Windows/Dialog/, owned by AppCore; reachable elsewhere via AppCore.showNotice / confirm). Presentation is async, so there is no nested run loop, and the presenter refuses a second dialog while one is up — that, not a flag, is what stops a held hotkey stacking dialogs. ↵ runs the primary action, Escape cancels, and Cancel always renders leading (the left button), matching macOS convention.
• A dialog has three independent axes; never let one infer another. The icon (DialogRequest.symbol, required) is always the subject's own glyph — the command being confirmed uses its SystemAction.sfSymbol, so the Restart dialog shows the same icon as the Restart row. Tone never picks an icon. The tone (DialogTone: .neutral / .success / .danger) tints only that glyph. The button takes its color from DialogAction.Role (.standard white / .destructive red / .cancel secondary), so a red-glyph security warning can still carry a plain white button — as "Import executable commands?" does. Resolve every glyph through SymbolImage, not Image(systemName:): some catalog symbols are bundled assets (toggleBluetooth). A button never prints its key cap; hovering it shows a Tooltip (DesignSystem/Tooltip.swift) instead, styled like the palette's own keycap chips.
• A transient readout is a HUD, not a dialog. VolumeHUDController's box is volume/mute only, since that one needs an actual level and number; every other success/info confirmation (system commands, Custom Commands, Snippets) goes through MessageHUDController's pill, whose trailing glyph is its DialogTone — a pill has no subject to name, so the dialogs' icon rule doesn't apply, and the mapping stays file-scoped so nothing can reach for it when building a DialogRequest. Both are driven by HUDPresenter, which owns the one-at-a-time / auto-dismiss / fade policy; a new HUD means a new presenter, not a second shape bolted onto an existing controller. See ui.md.
• Glass is for controls; content takes the panel recipe. glassEffect needs a backdrop to lens, so it only works inside a window that already has a VisualEffectView — the action capsule, the menu circle, PopoverMenu, a dialog's buttons. On a bare borderless panel it falls back to an opaque backing and shows as a dark edge. Both HUDs therefore use black panelDimming → VisualEffectView() → clipShape, exactly like a dialog.
• Read docs/ui.md before any restyle or new view. DesignSystem/Theme.swift is the single design-token source.
• DesignSystem/Scrolling/EdgeDissolve.swift and DesignSystem/Scrolling/ThinScrollbar.swift are off-limits. Both are tuned by eye against the palette's floating bars, so any edit is a visual regression. Do not touch them to fix a scroll bug, and never as a side effect of a restyle or refactor — needing to is the signal that the real fix belongs elsewhere (a scroll target, an inset, an intent). Edit either one only under an explicit task to change that look.

Project Layout

• Tinycast/DesignSystem/ — the shared visual primitives: Theme.swift is the design-token source, plus KeyCapChip, Tooltip, SymbolImage, VisualEffectView, PopoverMenu, SettingsComponents, Scrolling/ and Interaction/.
• Tinycast/Platform/ — the system shims: Permissions, LaunchAtLogin, CursorScreen, AppDisplayName, NotificationToken, AppPaths, Signposts and Images/.
• Tinycast/Palette/ — the palette shell: PalettePanel, PaletteWindowController, RootPaletteView, the PaletteScreen protocol, PaletteCoordinator and the PaletteState / PaletteMode / PasteTarget state types.
• Tinycast/Windows/ — the non-palette AppKit surfaces: AuxWindowController (Settings, About, Onboarding), Dialog/ and HUD/, kept separate because a dialog asks and a HUD reports, plus About/.
• Tinycast/Features/<Name>/ — one folder per feature, holding everything that feature owns: Launcher/, Clipboard/, Calculator/, Emoji/, Quicklinks/, Snippets/, Uninstall/, SystemActions/, CustomCommands/, HotKeys/, Backup/, WindowManagement/, Onboarding/. Larger features split into Model/ (pure — the standalone-harness inputs), Service/ (effects: stores, monitors, runners, AppKit glue), UI/ (screens, views and the feature's coordinator) and Settings/ (its own panes). A file under Model/ may not import AppKit or SwiftUI — that is the checkable form of the purity invariants above. Small features stay flat. Features/PaletteRowIndex.swift sits at the top level because the palette, not one feature, owns it.
• Tinycast/Features/Settings/ — the Settings shell only: SettingsRootView, SettingsTab, AppSettings, and Panes/ for the two panes no feature owns (General, Permissions). Every other pane lives with its feature. Each SettingsTab maps to one …SettingsView built on the SettingsPane / SettingsCard scaffold in DesignSystem/SettingsComponents.swift; the four launcher-category panes (Applications, System Settings, System Actions, Commands) are thin wrappers over the shared LauncherItemsCard.
• Tinycast/App/ — @main app, delegate and AppCore, the composition root.
• Tools/ — standalone test harnesses and the emoji generator.
• .github/workflows/release.yml — the entire release pipeline (see docs/development.md).

Naming vocabulary

A type's suffix says what it is. Each row below is a suffix, what it means, and — where the set is small enough to enumerate — every type that currently carries it, so a reader can tell a closed set from an open one. The table governs top-level types; a private nested helper is free to be named for its job.

A new type takes an existing suffix, or this table gains a row in the same commit.

Suffix	Means	Members
Store	Owns persisted state and publishes it	open (10)
Coordinator	A feature's action surface, called by AppCore and the palette	open (11)
Controller	Owns one AppKit window or surface	open (5)
Catalog	Pure static namespace over a built-in list	CommandCatalog, EmojiCatalog, SystemActionCatalog, WindowCommandCatalog
Index	A searchable collection, rebuilt as its inputs change	AppIndex, EmojiIndex, PaletteRowIndex
Runner	Performs one effectful operation on request	ShellCommandRunner, SystemActionRunner, UninstallRunner
Session	Transient state for one in-progress interaction	QuicklinkArgumentSession, ShortcutCaptureSession, UninstallSession
Policy	A pure decision — no state, no effects	the three Snippet…Policy types
Engine	A pure evaluator: input → output	CalcEngine, SnippetTemplateEngine
Monitor	Watches an external stream and reports changes; owns no policy	DoubleTapMonitor, RunningAppsMonitor
Scanner	Reads the filesystem to produce candidates	SettingsPaneScanner, UninstallScanner
State	Shared observable state that persists nothing itself	OnboardingState, PaletteState, VolumeState
Manager	Closed set of two. Sole owner of a subsystem's lifecycle and its policy, started from AppCore.start(). Do not add a third — a new type wanting this suffix wants Store, Monitor or Coordinator instead.	ClipboardManager, HotKeyManager

Manager survives on two types because neither alternative is honest. ClipboardManager polls, but it also owns the capture policy (sensitiveTypes, maxTextLength, internalType, the disabled-apps filter) and the paste-side handshake, which the two real Monitors do not. HotKeyManager persists bindings like a Store, but it also drives Carbon registration and double-tap dispatch.

Exceptions, each earning its own word:

• Launcher (AppLauncher, QuicklinkLauncher) — reserved synonym for an NSWorkspace.open wrapper. Clearer than Runner for opening things.
• Repository (SnippetRepository) — conflict-detecting, revision-checked file semantics that Store does not imply.
• Center (HotKeyCenter) — the Carbon registration layer specifically.
• Presenter (HUDPresenter) — owns the one-at-a-time / auto-dismiss / fade policy for both HUDs.
• Domain terms with no better alternative: SnippetTextInjector, WindowMover, HyperKeyTap.
• Registry and ViewModel are retired: a static table is a Catalog, shared app state is a State.
• SwiftUI-layer suffixes (View, Screen, Card, Row, Sheet) are a separate vocabulary and are not governed by this table.