Applescript

AppleScript Development Skill

Assist with all aspects of AppleScript development including creating files, writing code, compiling, running, debugging, and testing — both application scripting (via scripting dictionaries) and GUI automation (via System Events).

Creating New Files

When creating a new AppleScript file, always include the file header from CLAUDE.md using the AppleScript block comment style ((* *)), not /* */. AppleScript has no C-style comments.

• Block comments: (* ... *)
• Single-line comments: -- or #

Use the .applescript extension for source and .scpt for compiled output.

Compiling and Running

• Compile (syntax check, no execution): osacompile -o /tmp/out.scpt <script.applescript>
• Run: osascript <script.applescript>
• Compile to a runnable .app: osacompile -o <name>.app <script.applescript>

osacompile catches syntax errors but NOT runtime errors. Compiling clean does not mean the script runs — handler dispatch, missing UI elements, and permissions only surface at run time.

Code Quality

• Use tell ... end tell blocks scoped as tightly as possible; do not nest unrelated work inside an application's tell.
• Prefer explicit element paths over whose filters in hot loops, but use whose clauses for resilience when element indices shift.
• Wrap fragile UI lookups in try ... end try so one missing element does not abort the whole script.
• Use delay after UI actions that trigger animations or sheets; GUI automation races the UI otherwise.
• Name variables descriptively; avoid one- or two-letter names — some short tokens collide with reserved words and fail to parse (e.g. a bare rd was rejected).

Calling Your Own Handlers Inside a tell Block

Critical, compiler-invisible bug: inside a tell application / tell process block, an unqualified handler call like myHandler() is dispatched to the target application, not to your script. The target has no such handler, so it fails at run time even though it compiles clean.

Prefix calls to your own handlers with my (or of me):

tell application "System Events"
    tell process "Messages"
        my deleteAllConversations()      -- dispatched to the script
        if my clickAffirmative(window 1) then return
    end tell
end tell

Without my, AppleScript tries to send deleteAllConversations to the Messages process and errors.

GUI Automation (System Events)

• Requires Accessibility permission: System Settings > Privacy & Security > Accessibility, granted to the app that runs the script (Script Editor, Terminal, osascript, etc.). Every System Events call fails silently or errors without it.
• UI-element hierarchies (splitter group, scroll area, table, toolbar buttons) and menu/button titles shift between macOS releases. Treat any hardcoded path as version-specific.
• Use Accessibility Inspector (Xcode > Open Developer Tool > Accessibility Inspector) to confirm the live element tree and exact titles before relying on them.
• Key codes for keystrokes: key code 51 = Delete, key code 53 = Escape, key code 36 = Return, key code 0 using {command down} = Cmd+A.

Debugging

• Use log "message" statements; output appears in Script Editor's log pane or on stderr under osascript.
• Use display dialog (someVariable as text) for quick inspection of values mid-run.
• Errors report a line number and a (-NNNN) OSA error code — -2741 is a parser error, -2740 a syntax-position error, -1728 "can't get " (missing UI element), -25211 accessibility not authorized.
• For GUI automation, isolate the failing tell block and run it alone to confirm the element path.

Argument Handling

• If $ARGUMENTS is a filename ending in .applescript or .scpt, work with that file
• If $ARGUMENTS is "new ", scaffold a new file with the (* *) header
• If $ARGUMENTS is "run ", execute with osascript and report output
• If $ARGUMENTS is "check ", compile with osacompile to validate syntax
• Otherwise, treat $ARGUMENTS as a general AppleScript development request