Build and verify

A change is done when four things are true:

1. ./build.sh finishes with no errors.
2. You looked at the light and dark snapshots of every page you touched.
3. The snapshots match what the user story or reference screenshot asks for.
4. The grid checks pass (layout-grid skill).

App not made from the new-mac-app template (Xcode, XcodeGen, a menu bar utility, Swift 5)? Map the commands below with existing-app.md first.

Do not report a UI change as done from the code alone. SwiftUI code that compiles can still render an empty sidebar, clipped text, or unreadable dark mode.

1. Build

./build.sh            # release build, installs ~/Applications/<AppName>.app
./build.sh --debug    # faster build while iterating
./build.sh --open     # also restarts the app so the user sees the new build

Read the errors, fix them, and build again. Fix the first error first: later errors often come from it. If a new file is "not in scope" right after you created it, run swift package clean --scratch-path ~/Library/Developer/<AppName>/build.

2. Snapshot

Run the installed binary directly with a test database and a folder for the images. The app opens, walks through every sidebar page and every Settings tab in light and dark mode, saves one PNG per page and mode, and quits.

tools/snap.sh
# SNAPSHOT /tmp/<AppName>-shots/all-light.png
# ...
# SNAPSHOT done /tmp/<AppName>-shots

tools/snap.sh deletes the old test store (with its -wal and -shm files) and the saved window state first, then runs with sample data (APP_SEED=1). Without that, seed data goes stale, and one crashed run leaves a "reopen windows?" alert that hangs every later run.

Use APP_SNAPSHOT_PAGES=today,inbox to limit the pages. Add settings to include the Settings tabs.

In every image, look for three bugs agents often miss: a focus ring or selected text that nobody asked for, a scroll bar with nothing to scroll, and an empty band under short content. The fixes are in mac-design, "Windows open calm".

To see scroll bars as people with a mouse see them, add -AppleShowScrollBars Always after the binary path. It changes only this run.

Always use APP_STORE with a path in /tmp. Never take snapshots against the user's real database in ~/Library/Application Support/<AppName>/.

Seed data

Empty pages only show empty states. The template's Sources/<AppName>/SeedData.swift fills an empty test store when APP_SEED=1 is set. Grow it with the app: 10 to 20 items with long and short titles, dates in the past and future, every priority and status, and only what a person can create in the app.

Screen Recording permission

Snapshots use screencapture -l <window>, which shows glass, sidebars, and materials exactly as on screen. It needs Screen Recording permission for the app that runs the command (Terminal, Ghostty, or Claude). If a snapshot line ends with (fallback: ...), the permission is missing and sidebars and glass render blank. Ask the user to allow it in System Settings > Privacy & Security > Screen & System Audio Recording, then restart the terminal.

Missing snapshots

If every snapshot fails, or screencapture says "could not create image from window", the display is probably asleep: an unattended Mac turns it off. The template's snapshot mode wakes the display itself. For captures from outside the app (like window-shot.sh), run caffeinate -u -t 2 first.

If some states print "no window" while others work, another app hid yours during the run. Computer use does this to apps it does not control, and so does Hide Others. The template's snapshot mode un-hides the app and brings the window forward before each capture. Run it again, and avoid using computer use in another session at the same time.

3. Check the grid

tools/grid-lint.sh
swift tools/check-layout.swift /tmp/<AppName>-shots/*-layout.json

Both print PASS. On a FAIL, call the Skill tool with layout-grid: it has the rules, the overlay, and a table of fixes.

4. Look

Open every PNG with the Read tool and check, in this order:

• Nothing is blank, clipped, or overlapping. Text fits. Sidebars show their items.
• Dark mode is readable. No fixed white or black surfaces.
• The page matches the story or the reference screenshot (layout, labels, order).
• The mac-design rules hold: glass only on controls, one accent, SF Symbols, system text styles, empty states that invite the first action.

Describe what you see in one or two sentences per page in your report, and name the PNG paths so the user can open them.

5. Interaction checks

Snapshots show state, not behavior. Run tools/selftest.sh (exit 0 when every check passes) and add a check for each new action. The test-mac-app skill covers unit tests, the self-test, key events, the menu check from outside, and a debug bridge.

Inactive windows

Gray traffic lights mean the window was not key when it was captured: sidebar text, selection, and toggles look dimmer than in use. A snapshot of an inactive window does not count as reviewed. Run the snapshots again while nobody else uses the screen, and do not "fix" dim text you only see there.

Debug output and private screens

A GUI app started with its output going to a file buffers print, and the lines are lost when the process is killed. Write debug lines to stderr (FileHandle.standardError.write) behind an environment flag.

Do not take full-screen captures to check your app: they show the user's other windows. Capture your own window, or add a mode to the app that renders the state you want to see (prefilled text, an open sheet).

6. Commit

When the build is clean and the snapshots look right, commit with a message that says what the user can now do: "Add tasks from the quick-add panel", not "Update views".

Done when the four conditions at the top hold and the change is committed.