cua-driver

name

cua-driver

description

Drive native macOS apps and browser UI through OpenClicky's local computer-use MCP background lane, backed by Cua. Snapshot state, prefer AX element_index actions, use explicit pixel/foreground paths only when the current OpenClicky tool surface exposes them, and verify via re-snapshot. Use when the user asks you to operate, drive, automate, or perform a GUI task in a real macOS application on the host.

cua-driver

Orchestrates macOS app automation through Cua. In OpenClicky's managed runtime, this skill is the instruction surface for the Agent Mode computer-use MCP background lane. OpenClicky also has product routes for native Swift CUA, foreground app/URL opens, Background Computer Use pixel clicks, and the external-control bridge. Treat the app/router code as the source of truth for those lanes; this skill tells agents how to operate when the callable tool server is computer-use. Call the local MCP tools by name (launch_app, get_window_state, click, set_value, etc.) instead of shelling out to cua-driver.

Whenever a user asks to drive a native macOS app or browser UI, follow the loop in this skill rather than calling tools ad-hoc. The snapshot-before-action invariant is not optional and silently breaks if you skip it.

OpenClicky managed runtime rules

OpenClicky ships Cua as a local computer-use MCP server backed by ClickyComputerUseRuntime. That helper is spawned by Codex inside Clicky.app, so macOS attributes Accessibility and Screen Recording use to OpenClicky itself. In this MCP lane:

• Use the computer-use MCP tools directly. Do not run the cua-driver CLI, open, AppleScript, cliclick, browser CLIs, or other GUI automation shims to operate apps.
• Do not treat OpenClicky's own voice/router/native paths as violations of this skill. The app may intentionally use NSWorkspace for foreground app or URL opens, native Swift CUA for screen-coordinate clicks/typing/keys, Background Computer Use /v1/click for window-screenshot pixel clicks, or the external-control bridge for visible guidance and explicit coordinate clicks. Agents should not reimplement those paths with shell shims.
• For external account-backed apps, prefer a connected structured MCP or Composio integration when one is exposed and suitable. Do not silently use Computer Use as a substitute for a missing/expired connector on private account data, and do not offer to connect that integration yourself. Tell the user to open OpenClicky Settings -> Integrations and connect/reconnect the named app, offer voice/in-app guidance through setup, and do not use Computer Use to operate OpenClicky's own Settings/Integrations setup flow. Use visible UI only for the original third-party app task when the user asked for it, approved it, or the app has no shipped connector route.
• Screenshots and focused-window context do not choose the Computer Use route by themselves. If an integration-capable app such as LinkedIn, Gmail, Slack, Notion, Linear, GitHub, Calendar, Drive, Docs, or Sheets is visible, still prefer the structured MCP/Composio route first unless the user explicitly asks to click, type, or use that visible page/window.
• Keep work backgrounded by default. The user should be able to keep typing in their current app while you operate another app or browser window.
• For a new browser task, resolve the user's default HTTPS browser and open the target URL in a new background window with launch_app({bundle_id: <default_browser_bundle_id>, urls: [...]}). This preserves the user's current tab/window and their normal logged-in browser profile.
• If the user explicitly asks you to work in "this tab", "this window", "the page I have open", or the screenshot clearly shows the target browser context they want operated, use that existing window/tab after a fresh snapshot instead of opening a new one.
• Do not pass --user-data-dir or other isolated-profile flags; they log the agent out of the accounts the user expects to use.
• Prefer AX and app-scoped actions: click({pid, window_id, element_index}), right_click({pid, window_id, element_index}), set_value, type_text, press_key, hotkey, scroll, page, and get_window_state.
• OpenClicky's computer-use MCP lane does not expose move_cursor, drag, double_click, recording, replay, or zoom in this build. Prefer AX/page actions in this skill. Coordinate clicks are valid only through explicit OpenClicky pixel/foreground surfaces that document their coordinate space; do not invent raw CGEvent, cliclick, or shell-based pixel input.
• Stop before purchases, sends, deletes, payments, account changes, submitting forms, or other irreversible actions unless the user explicitly approved that exact step.

The MCP background contract — read this first

For this computer-use MCP skill, default to preserving the user's frontmost app. Users should be able to keep typing in their editor while an agent drives another app in the background. This is a lane-specific contract, not a statement that OpenClicky's app code must never foreground anything: explicit voice app-open requests, native CUA, Background Computer Use pixel actions, the visual-control bridge, and product-managed foreground flows are separate OpenClicky routes.

Before running any shell command, ask: "does this raise, activate, foreground, or make-key any app?" If yes, don't run it. Every one of the commands below activates the target on macOS and is therefore forbidden inside this MCP lane. If the user explicitly asks for frontmost state and the current OpenClicky tool surface exposes a foreground/native route, use that documented route. If it does not, explain that this skill can keep working in the background but cannot foreground the app through computer-use.

• Every form of the open CLI — open -a <App>, open -b <bundle-id>, open <file>, open <path-to-App.app>, open <url> — always activates. macOS routes all forms through LaunchServices, which unhides and foregrounds the target regardless of whether you passed an app name, a bundle id, a document, a URL, or the bundle path itself. The activation happens even when the only intent was "start the process." Never use open for any app launch. This includes launching a just-built .app from a local build dir (e.g. open build/Build/Products/Debug/MyApp.app) — resolve the CFBundleIdentifier from Info.plist and use launch_app with that id. If foregrounding is genuinely needed, use a documented OpenClicky foreground/native route rather than shelling out.

• osascript -e 'tell application "X" to activate' — activates by design. Same for ... to open <file>, ... to launch, and anything with activate in the tell block.

• osascript -e 'tell application "System Events" to ... frontmost' in a mutating form (setting frontmost rather than reading it).

• AppleScript files that invoke activate, launch, or open against the target app.

• cliclick (moves the user's real cursor to the target coords before clicking — a focus-steal-equivalent even if the app's window state is unchanged).

• CGEventPost with cghidEventTap targeting a coordinate over a different app's window (warps the cursor, possibly activates on hit).

• AppleScriptTask, NSAppleScript, Process wrapping osascript that contains any of the above.

• NSRunningApplication.activate(options:) called from your own helper binary — same class.

• Dock clicks and any open invocation (see the first bullet — every form of open goes through LaunchServices which activates, full stop).

• Keyboard shortcuts that semantically mean "focus here" — most notably Chrome / Safari / Arc's ⌘L (focus omnibox) and Finder's ⌘⇧G (Go to Folder). These aren't pure key events — the receiving app interprets "user wants to type here" as activation intent and raises its window to be key. Even when delivered to a backgrounded pid via hotkey, the downstream app pulls focus. For omnibox navigation specifically, the correct path is to resolve the user's default browser bundle id and call launch_app({bundle_id: <default_browser_bundle_id>, urls: ["https://..."]}) — no omnibox dance, no ⌘L, no focus-steal. Do NOT try set_value on the omnibox for navigation: browser commit logic often requires a "user-typed" signal that neither an AX value write nor CGEvent.postToPid keystrokes supply from a backgrounded pid. The URL may land in the field but Return can fire as a no-op. See WEB_APPS.md → "Navigate to a URL" for the full default-browser pattern. The general principle: a shortcut that says "put my cursor inside this app" is a focus-steal; a shortcut that says "do this thing" (copy, save, quit) is fine.

• Tab-switching shortcuts in browsers (⌘1..⌘9, ⌘], ⌘[, ⌘⇧[, ⌘⇧]) are visibly disruptive even when delivered to a backgrounded pid. The app's key handler processes the shortcut, the window re-renders the new tab's content, the user sees their tabs flipping. There is no AX-only workaround: page content (HTML, form state, AXWebArea) populates only for the focused tab; inspecting a background tab requires activating it, which is the visible flip. Observed with Dia; the same mechanic applies to every Chromium-family browser (Chrome, Arc, Brave, Edge).

  Prefer the windows-over-tabs pattern: for each URL you need to drive backgrounded, resolve the user's default browser and use launch_app({bundle_id: <default_browser_bundle_id>, urls: [url]}) so browsers open each URL in a new window where supported. Each window has its own window_id, its own AX tree, and can be inspected / interacted with via element_index without activating or switching anything. Tabs are a UX grouping for humans; cua-driver workflows should default to windows. See WEB_APPS.md → "Tabs vs windows" for the full pattern.

  Tab-title enumeration (read-only) IS safe — walk a window's toolbar AX tree for AXTab / AXRadioButton children and read their AXTitles. Tab switching (activating one) is not.

If exact frontmost-app identity matters and the local computer-use tools cannot answer it, stop and explain the limitation. Do not shell out to osascript as a side channel.

Corollary — the AXMenuBar rule. AXMenuBarItem + AXPick dispatches at the AX layer regardless of which app is frontmost, but macOS's on-screen menu bar always belongs to the frontmost app. If you drive a backgrounded app's menu bar, the AX call succeeds but the viewer sees the dispatch rendered over the frontmost app's menu bar — confusing in any observed session and routinely a silent no-op too, because action menu items go DISABLED when their owning app isn't the key window. So: only use menu-bar navigation when the target is already frontmost. For backgrounded targets, read state via in-window AX (window title, toolbar AXStaticText) and dispatch via in-window element_index actions. Pixel clicks are not the default path in this MCP lane; use them only through explicit OpenClicky pixel/foreground surfaces that document their coordinate space. Full rationale in "Navigating native menu bars" below.

Inside this MCP lane, "open <app>" means launch, not activate. launch_app is the correct path for background process startup: it is idempotent, returns the pid, and is designed for background operation. If OpenClicky's voice/native router handled the same phrase as an explicit foreground app-open, that is app behavior outside this skill. Do not override it, and do not recreate it with open or AppleScript.

Defaults — always prefer the local MCP tools over shell shims

Every reference to click(...), get_window_state(...), etc. in this skill means call the same-named tool on OpenClicky's local computer-use MCP server. The standalone cua-driver CLI examples in upstream docs are for local development only; they are not the product runtime path.

Intent → tool mapping. If you find yourself reaching for the right column while operating through computer-use, something has gone wrong — re-read "The MCP background contract" above:

Intent	Use	Don't use
Open / launch an app	launch_app({bundle_id}) or launch_app({bundle_id, urls:[...]})	open -a, osascript 'tell app … to launch/activate/open'
Find a pid	list_apps or launch_app's return	pgrep, ps, osascript frontmost
Enumerate an app's windows	list_windows({pid}) — or read the windows array launch_app already returns	osascript 'every window of app …'
Click / type / scroll / keys	click, type_text, scroll, press_key, hotkey	osascript, cliclick, raw CGEvent, open <url>
Drag / drag-and-drop / marquee select	Not exposed in the computer-use MCP lane; use only an explicit OpenClicky foreground/pixel route if the current tool surface documents one	cliclick dd:, osascript drag
Screenshot	screenshot or the PNG in get_window_state	screencapture
Quit an app	ask the user first, then hotkey({pid, keys:["cmd","q"]})	kill, killall, pkill
Hand a file/URL to an app	launch_app({bundle_id, urls:[<path>]})	open -a <App> <path>, open <url>

The frontmost handoff

The computer-use MCP lane has no activation tool and does not allow osascript activation. If the user explicitly asks for frontmost state ("bring Chrome to the front", "make it frontmost", "I want to see X"), use an explicit OpenClicky foreground/native tool only if the current tool surface exposes one. If only the computer-use MCP lane is available, say that this build can keep working in the background but cannot foreground the app through computer-use.

When a Computer Use call surprises you, diagnose the local MCP state first:

• Tiny screenshot / empty tree_markdown? Check get_config → capture_mode. Default "som" returns both the AX tree and screenshot. "vision" omits the AX tree (PNG only), "ax" omits the PNG. If a snapshot lacks a tree, capture_mode is almost certainly "vision" — either reason purely from the PNG or flip to "som" / "ax" via set_config.
• has_screenshot: false? The window capture failed (transient race against a close, or the window has no backing store yet). Re-snapshot; if persistent, pick a different window_id via list_windows.
• Invalid element_index / No cached AX state? You either skipped get_window_state this turn or passed a different window_id than the one the snapshot cached against. The cache is keyed on (pid, window_id) — indices don't carry across windows of the same app. Re-snapshot with the same window_id you're about to click in.
• Sparse Chromium AX tree? Retry get_window_state once — the tree populates on second call.

Only after those are ruled out, and only if the user's action genuinely needs frontmost state, hand off to an explicit OpenClicky foreground route when one is available. Otherwise stop and explain the foreground requirement. The computer-use MCP lane does not expose an activation tool.

Self-check pattern

Before every Computer Use tool call that touches any macOS app (launching, opening, clicking, typing, scripting, screenshotting), run the self-check:

1. Does this command foreground the target? If yes — stop and translate to the Computer Use equivalent from the mapping table, or use an explicit OpenClicky foreground/native route if that is the selected tool surface.
2. Does this command move the user's real cursor? (cliclick, any CGEventPost at cghidEventTap over another app's window). If yes — stop; use an AX element action, keyboard shortcut, or page action, or use a documented OpenClicky pixel route when the tool surface explicitly exposes one.
3. Does this command bypass Computer Use entirely? (osascript mutating GUI state, AppleScript files, external helpers.) If yes — stop; find the local MCP tool that does the intent.

If all three are "no," the command is safe. If you can't answer, default to stop and ask rather than proceed. A single open -a run by accident kills the demo, the trust, and the user's in-flight editor state.

Prerequisites — check before starting

1. Confirm the computer-use MCP server is available in the current Codex session. OpenClicky starts it automatically from the bundled ClickyComputerUseRuntime helper.
2. Call check_permissions({"prompt": false}). If Accessibility or Screen Recording is missing, stop and ask the user to grant those permissions to Clicky.app in System Settings.
3. Do not start daemons, install CuaDriver.app, or invoke standalone shell commands. In OpenClicky, the MCP server is already the daemon.

Using the local MCP tools

Tool names are snake_case and are called directly through the computer-use MCP server.

Canonical multi-step workflow:

launch_app({"bundle_id":"com.apple.calculator"})
# -> {pid: 844, windows: [{window_id: 10725, ...}]}
get_window_state({"pid":844,"window_id":10725})
click({"pid":844,"window_id":10725,"element_index":14})
get_window_state({"pid":844,"window_id":10725})

Agent cursor overlay

Visual cursor overlay for demos and visible progress. Default: enabled. Toggle with set_agent_cursor_enabled({"enabled":true|false}). A triangle pointer Bezier-glides to each click target, ring-ripples on landing, idle-hides after ~1.5s. Motion knobs: set_agent_cursor_motion takes any subset of start_handle, end_handle, arc_size, arc_flow, spring — tuneable at runtime, persisted to config.

OpenClicky's MCP helper bootstraps the AppKit runloop required by the overlay.

The core invariant — snapshot before AND after every action

Every action MUST be bracketed by get_window_state(pid, window_id):

• Before — the pre-action snapshot resolves the element_index you're about to use. Indices from previous turns are stale; the server replaces the element index map on every snapshot, keyed on (pid, window_id). Indices from turn N don't resolve in turn N+1, and indices from window A don't resolve against window B of the same app. Skip this and element-indexed actions fail with No cached AX state.
• After — the post-action snapshot verifies the action actually landed. Without it you can't tell a silent no-op from a real effect. The AX tree change (new value, new window, disappeared menu, disabled button, etc.) is your evidence that the action fired. If nothing changed, the action probably failed silently — say so, don't assume success.

This applies to pixel clicks too — re-snapshot after to confirm the click landed on the intended target.

Why window selection is the caller's job now

get_app_state used to pick a window for you via a max-area heuristic that returned the wrong surface on apps with large off-screen utility panels. Concrete reproducer: IINA's OpenSubtitles helper (600×432 off-screen) out-area'd the visible 320×240 player window, so get_app_state(pid) screenshot'd the invisible panel and clicks landed there silently. The new get_window_state(pid, window_id) makes the caller name the window explicitly — the driver validates that the window belongs to the pid and is on the current Space, then snapshots exactly what was asked for. Enumerate candidates via list_windows or read the windows array launch_app already returns.

Behavior matrix

Two orthogonal axes shape what the agent can do.

capture_mode → addressing mode

capture_mode	get_window_state returns	Use for actions
som (default)	tree + screenshot	element_index preferred; pixels are diagnostic only in OpenClicky
ax	tree only (no PNG)	element_index only
vision	PNG only (no tree)	read-only visual inspection in OpenClicky — see SCREENSHOT.md

vision was renamed from screenshot — the old name still decodes as a deprecated alias, so an on-disk "capture_mode": "screenshot" keeps working. Default is som so element_index clicks work the first time a user calls get_window_state; the other modes are opt-in when the caller specifically doesn't want one half of the work. Note the tool named screenshot is separate (raw PNG, no AX walk) and unrelated to the capture mode.

When a snapshot looks wrong (tiny screenshot / empty tree), call get_config and inspect capture_mode before anything else.

Pure-vision mode has its own caveats — the model's vision pipeline downsamples dense text aggressively, so pixel grounding takes multiple correction cycles on text-heavy UIs. Read SCREENSHOT.md before driving anything in that mode; it documents the iterate/annotate/verify recipe plus the JPEG-over-PNG finding.

Window state → what works

state	get_window_state	click/set_value (AX)	press_key commit (Return/Space/Tab)	pixel click in explicit OpenClicky routes
frontmost	✅	✅	✅	native/bridge route when explicitly exposed
backgrounded / visible	✅	✅	✅	BCU window-screenshot route when explicitly exposed
minimized (Dock genie)	✅	✅ (no deminiaturize — AX actions fire on the minimized window in place)	❌ silent no-op / system beep — use set_value or click equivalent	❌ no on-screen bounds
hidden (hides=true / NSApp.hide)	✅	✅	depends	❌
on another Space	⚠️ AX tree often stripped to menu-bar-only on SwiftUI apps (System Settings) — AppKit apps usually fine. Response carries off_space: true + window_space_ids so you can detect it	✅	✅	❌ window not in current-Space list

Critical cell — minimized + keyboard commit. The keystroke reaches the app but AX focus doesn't propagate to renderer focus on a minimized window. Workarounds in order of preference: set_value to write the field's entire value directly, or AX-click a commit-equivalent button (Go, Submit, checkbox). Tell the user the window needs to un-minimize only as a last resort.

The canonical loop

launch_app(target)
  → pick window_id from the returned `windows` array
    (or call list_windows(pid) separately)
  → get_window_state(pid, window_id)
    → [act]  # every action also takes (pid, window_id)
  → get_window_state(pid, window_id) → verify

launch_app now returns a windows array alongside the pid, so the common case collapses to two calls (launch_app → get_window_state) without a separate list_windows hop.

1. Resolve target pid — always via launch_app

Always start with launch_app, whether or not the target is already running. It's idempotent (relaunching returns the existing pid with no side effects) and gives you the pid in one call — no list_apps hop.

• launch_app({bundle_id: "com.apple.finder"}) — preferred, unambiguous.
• launch_app({name: "Calculator"}) — when bundle_id isn't known.

launch_app is the background-safe launch primitive for this MCP lane: agents drive apps in the background while the user keeps typing in their real foreground app. In Cua v0.2.0, LaunchServices is called without activating the target, menu hotkey delivery restores the previous frontmost app immediately after posting the key, and an internal FocusRestoreGuard catches NSApp.activate(ignoringOtherApps:) calls the target makes during application(_:open:) and clobbers the frontmost back to what it was before the launch. That guard is why launch_app with urls (e.g. {"bundle_id": "com.colliderli.iina", "urls": ["~/video.mp4"]}) is safe even for apps that normally foreground on media-load (Chrome, Electron, media players). The target window may become visible behind the user's current app, but it must not become frontmost.

If the user explicitly wants the window foregrounded (usually for a demo or recording), hand off to an explicit OpenClicky foreground/native route if the current tool surface exposes one. Otherwise, tell the user to bring it forward themselves — Dock click, Cmd-Tab, or Spotlight. Do not reach for open / osascript activate as a shortcut to make the window visible inside this MCP lane.

Never shell out to any form of open (including open <path-to-App.app> for a just-built binary — resolve the bundle id from Info.plist and use launch_app with that), osascript 'tell app … to launch/open', or similar. Those paths activate the target, bypass the driver's focus-restore guard, and require a Bash permission prompt the agent loop shouldn't be burning on app launch. See "Prefer the local MCP tools over shell shims" above for the full intent → tool mapping.

list_apps is for app-level discovery (answering "what's installed / running / frontmost?") — not part of the core action loop. Skip it in the loop. For window-level questions — "does this app have a visible window?", "which Space is this window on?", "which of this pid's windows is the main one?" — call list_windows instead; the app record doesn't carry window state on purpose. In the common single-window case you can skip list_windows entirely and read the windows array that launch_app already returned.

2. Snapshot and act by element_index

Call get_window_state({pid, window_id}) with the window_id from launch_app's windows array (or a fresh list_windows({pid}) if you're interacting with a long-lived process). The default som capture_mode returns both the AX tree and screenshot, so the canonical loop works immediately without any config change. The rest of this section walks through som mode. If you're in vision mode (PNG only, no AX tree), flip back with set_config({"key": "capture_mode", "value": "som"}).

In som mode (the default) the response carries:

• tree_markdown — every actionable element tagged [N]. That N is the element_index. The tree can be very large (Finder is ~1600 elements, ~190 KB); when it exceeds token limits, inspect the returned file/path or re-snapshot a narrower target window.
• screenshot_file_path — absolute path to the saved screenshot when screenshot_out_file was passed. Absent otherwise.
• screenshot_width / _height / _scale_factor — dimensions of the captured image. Present whenever a screenshot was taken. Getting the screenshot as a file:

Pass screenshot_out_file when using get_window_state and you need a file path instead of inline image content:

{"pid": N, "window_id": W, "screenshot_out_file": "/tmp/shot.jpg"}

The MCP image content block is omitted from the response when this param is set, so the model receives the AX tree and screenshot_file_path.

Reason over both the tree AND the screenshot — they're complementary, not redundant. In som mode every turn's get_window_state gives you both halves and you should pull signal from each:

• The AX tree tells you what's clickable — roles, labels, element_index handles, advertised actions, parent-child structure. This is the ground truth for dispatching.
• The screenshot tells you which one — the tree often has many buttons with similar or empty labels ("Delete", "OK", anonymous UUID-labeled buttons, five AXStaticText = " "), and visual context disambiguates. Captions, colors, layout relationships visible in pixels often don't show up in the AX tree at all (especially in Chromium / Electron / web content).

Canonical pattern: look at the screenshot to decide "the blue Subscribe button on the top-right of the video card", then walk the tree to find the matching AXButton and dispatch by its element_index. Don't try to do it from just the tree — you'll pick the wrong element when labels repeat. Don't try to do it from just the screenshot — you lose the reliable AX-action path and the safe backgrounded-dispatch.

Standalone Cua can support coordinate-based input for canvas, video, WebGL, or custom-drawn surfaces that are not reachable through AX. OpenClicky's MCP background lane should still prefer AX/page actions, but app-managed routes may expose coordinate clicks with explicit coordinate spaces: native Swift CUA uses global AppKit screen points, and Background Computer Use /v1/click uses window-screenshot pixel coordinates. If AX, keyboard, and page cannot reach the target, use only those documented OpenClicky pixel routes when the current tool surface exposes them; otherwise stop and report the missing capability instead of guessing.

The actions=[...] list on each element is advisory, not authoritative. cua-driver does not pre-flight check against it — click({pid, element_index}) always attempts AXPress (or the action you pass) and surfaces whatever the target returns. Many apps accept AXPress on elements that don't advertise it — Chrome's omnibox suggestion AXMenuItem is a live example. Try the click first — pivot only on the returned AX error code.

Dispatch table (every row assumes a (pid, window_id) pair from the last get_window_state; window_id is required alongside element_index):

Intent	Tool	Notes
List an app's windows	list_windows({pid})	returns window_id, title, bounds, z_index, is_on_screen, on_current_space. Already included in launch_app's response — only call this for long-lived pids
Snapshot a window	get_window_state({pid, window_id})	returns tree_markdown + screenshot_*; populates the (pid, window_id) element_index cache
Left click	click({pid, window_id, element_index})	default action: "press". Prefer element_index in this MCP lane; use coordinate forms only when the current OpenClicky tool descriptor documents them.
Double-click / open	Use click({pid, window_id, element_index, action: "open"}) when the element advertises an open action	double_click is not exposed in the computer-use MCP lane because it can fall back to pixel stamping.
Right click / context menu	right_click({pid, window_id, element_index}) or click({pid, window_id, element_index, action: "show_menu"})	Chromium web-content coerces pixel right-click to left — see WEB_APPS.md
Type at cursor	type_text({pid, text, window_id, element_index})	AXSelectedText write; focuses first
Set whole field value	set_value({pid, window_id, element_index, value})	sliders, steppers, text fields; use for keyboard-commit workarounds on minimized windows
Scroll	scroll({pid, direction, amount, by, window_id, element_index})	synthesizes PageUp/PageDown/arrows via SLEventPostToPid
Focus + send key	press_key({pid, key, window_id, element_index, modifiers})	element_index sets AXFocused, then posts key
Send key to pid	press_key({pid, key, modifiers})	no focus change; key goes to pid's current focus
Modifier combo	hotkey({pid, keys})	e.g. ["cmd","c"]; posted per-pid, not HID tap
Unicode keystrokes	type_text({pid, text, delay_ms})	AX write with automatic CGEvent fallback; reaches Chromium/Electron inputs

All keyboard/text primitives require pid. There is no frontmost-routed variant — every key goes to the named target via CGEvent.postToPid, so the driver cannot leak keystrokes into the user's foreground app.

Why element_index is the primary path: works on hidden / occluded / off-Space windows, no focus steal, stable across rebuilds, labels tell you what you're clicking. If AX cannot reach the target, use keyboard shortcuts or page where possible; otherwise use an explicit OpenClicky pixel route only when the current tool surface documents it.

Pixel-coordinate clicks

Pixel clicks are supported in OpenClicky only through explicit routes with explicit coordinate spaces. Do not infer that every click tool uses the same coordinates.

• computer-use MCP element clicks use (pid, window_id, element_index).
• Background Computer Use /v1/click uses the focused window screenshot pixel coordinate returned by that BCU capture, not global display points.
• Native Swift CUA and the external-control bridge use global AppKit screen points, matching screenshot displayFrame metadata.

Screenshots in this MCP skill are primarily for visual disambiguation: use them to choose the right AX element, then dispatch by element_index. Translate pixels into clicks only when the current OpenClicky tool descriptor explicitly says that is the accepted input space.

If the target is a canvas, video player, WebGL surface, game viewport, or custom-drawn control with no useful AX tree, try reachable alternatives first: keyboard shortcuts, command palettes, toolbar controls, or the page tool. If those cannot perform the task, stop and tell the user the action needs an OpenClicky pixel/foreground route that is not exposed in the current tool surface.

For browser video playback, prefer page or keyboard controls where available, such as press_key({pid, key: "k"}) for YouTube-style players or press_key({pid, key: "space"}) for a focused generic player. Verify with a fresh snapshot.

Canvases, viewports, games (Blender, Unity, GHOST, Qt, wxWidgets)

Apps whose main surface is an OpenGL / Metal / Qt / wxWidgets viewport expose no useful AX tree — the whole surface is one opaque AXGroup or AXWindow from AX's perspective. Per-pid event paths (SLEventPostToPid, CGEvent.postToPid) are filtered by the viewport's own event-source check and silently dropped — the event loop wants "real HID origin".

There is no general AX/page backgrounded path that reaches these apps today in the computer-use MCP lane. Use an explicit OpenClicky pixel/foreground route only when the current tool surface exposes one; otherwise stop and say the task requires a pixel/foreground capability instead of silently escalating.

Navigating native menu bars (AXMenuBar)

Only drive the menu bar when the target app is frontmost. This is the single most-misused cua-driver capability. If the target is backgrounded, don't reach for AXMenuBarItem + AXPick — use in-window element_index, toolbar controls, command palettes, or keyboard shortcuts instead. Two reasons, one functional and one perceptual:

• Functional: menu items that touch document/playback/editor state go DISABLED when their owning app isn't the key window (Preview rotate, IINA speed change, most editor commands). AXPick
  • AXPress will dispatch successfully from the driver's side but no-op at the target — you get a silent false-pass.
• Perceptual (matters for demos, screen recordings, and anything the user watches live): macOS's screen-rendered menu bar always belongs to the frontmost app. AXPick on a backgrounded app's AXMenuBarItem dispatches to that app's per-process menu at the AX layer, but any visible menu render happens over the frontmost app's menu bar — the viewer sees an IINA submenu flashing on top of Chrome's menus, which reads as "the agent clicked the wrong app." The AX call was correct; the frame the user sees is not. For recorded or observed sessions, this is an integrity bug even though it's not a correctness bug.

Good decision rule: if the target is not already frontmost, do not use AXMenuBarItem at all. For reading in-window state, snapshot the window AX tree — most apps expose the same state via an in-window AXStaticText, title bar, or toolbar. For dispatching actions, use in-window element_index targets, toolbar controls, command palettes, keyboard shortcuts, or page where available. If the only workable path is a coordinate/pixel click, stop and say that the current computer-use MCP lane does not expose the needed pixel mode, unless another explicit OpenClicky foreground/pixel route is available.

When the target IS frontmost, the menu-bar flow below is fine and the canonical path for menus.

The two-snapshot pattern (target frontmost only)

Menu contents are a two-snapshot flow. Closed AXMenu subtrees are deliberately skipped during snapshot — otherwise every app's File / Edit / View hierarchy plus every Recent Items macOS has ever seen would inflate the tree 10-100x. But once a menu is open, its AXMenuItem children do receive element_index values so you can click them normally.

1. Find the [N] AXMenuBarItem "<Menu Name>" in the tree.
2. click({pid, element_index: N, action: "pick"}) — menu bar items implement AXPick ("open my submenu"), not AXPress. Using the default action on an AXMenuBarItem is a no-op.
3. Re-snapshot. The expanded menu's items now appear under the bar item as [M] AXMenuItem "<Item Name>".
4. Click the target item — most items respond to AXPress (default action). Submenus nest under the item and are walked the same way.
5. Re-snapshot and verify.

If you ever need to back out without selecting, press_key({pid, key: "escape"}) closes the open menu. Leaving a menu expanded between turns poisons subsequent snapshots for that pid.

Commands gated on the target being frontmost

Some menu items and global shortcuts (Preview's Tools → Rotate Right, ⌘R; anything in the View menu that manipulates the current document; most editor commands) are disabled unless the target app is the key / frontmost window. You'll see it in the AX tree as DISABLED on the menu item even though the user's intent is obviously valid.

Before activating, confirm you're in this narrow case — the menu item still reads DISABLED after a fresh snapshot AND the action the user requested genuinely requires frontmost (Preview rotate, View menu document manipulation, editor commands). If either check fails, don't activate.

When both checks pass, the computer-use MCP lane still does not expose an activation tool and does not allow osascript activation. Hand off to an explicit OpenClicky foreground/native route if the current tool surface exposes one; otherwise tell the user the action requires the target app to be frontmost. If they bring it frontmost, re-snapshot and continue.

Web-rendered apps (browsers, Electron, Tauri)

For Chrome / Edge / Brave / Arc / Safari, Electron apps (Slack, VSCode, Notion, Discord), and Tauri apps — see WEB_APPS.md.

Covers: sparse AX tree population (retry-once pattern for Chromium), URL navigation via launch_app({bundle_id, urls:[...]}), forbidden omnibox fallbacks (⌘L, URL-like type_text, URL-like set_value), the set_value workaround for ordinary keyboard commits on minimized windows (Return silently no-ops — symptom is a macOS system beep), scrolling via synthetic PageUp/Down keystrokes, in-page clicks, and typing into web inputs.

Chromium web content specifically also coerces right_click back to left — use element_index for AX-addressable targets and accept the limit otherwise.

Browser JS primitives — page tool and get_window_state(javascript=)

When the AX tree doesn't expose the data you need (common in Chromium/Electron — the tree is sparse for web content), use the page tool or the javascript param on get_window_state to query the DOM directly via Apple Events. Requires "Allow JavaScript from Apple Events" to be enabled — see WEB_APPS.md for the setup path.

Three actions on the page tool:

• page({pid, window_id, action: "get_text"}) — returns document.body.innerText. Fastest way to read page content, prices, article text, or any raw text the AX tree truncates or omits.

• page({pid, window_id, action: "query_dom", css_selector: "a[href]", attributes: ["href"]}) — runs querySelectorAll and returns each match's tag, text, and requested attributes as a JSON array. Use for table rows, link hrefs, data attributes, structured page data.

• page({pid, window_id, action: "execute_javascript", javascript: "..."}) — raw JS. Wrap in an IIFE with try-catch. Don't use this for elements already indexed by get_window_state — click and set_value are more reliable there.

Co-located read — get_window_state with javascript:

get_window_state({pid, window_id, javascript: "document.title"})

Runs the JS and appends the result as a ## JavaScript result section alongside the AX snapshot — one round-trip instead of two. Use this when you need both the element tree (for subsequent clicks) and some page data in the same turn.

Decision rule — AX vs JS:

Need	Use
Click / type into an element	get_window_state → click / set_value (AX, works backgrounded)
Read text the AX tree drops	page(get_text) or get_window_state(javascript=)
Scrape structured data (tables, hrefs)	page(query_dom)
Trigger JS events / mutations	page(execute_javascript)

Supported backends:

App type	How	Context
Chrome / Brave / Edge	Apple Events execute javascript	Full DOM ✅
Safari	Apple Events do JavaScript	Full DOM ✅
Electron (VS Code, Cursor…)	SIGUSR1 → V8 inspector → CDP	Main process only: process, Buffer — no document, no require in sandboxed apps
Electron debug-port page target	Future/runtime-explicit only	Full DOM when exposed

Electron sandbox note: SIGUSR1 connects to the Node.js main process. Sandboxed Electron apps (VS Code, Cursor) strip require and Electron APIs there. Useful for: process.env, process.versions, process.cwd(), process.pid. Do not relaunch user apps with debugging flags in OpenClicky's default runtime; only use a debug-port page target if the runtime already exposes it.

Arc returns no values; Firefox has no JS-via-AppleEvents support — see WEB_APPS.md for the full matrix.

3. Re-snapshot and verify — mandatory

Always call get_window_state({pid, window_id}) after the action. This isn't optional verification — it's the second half of the snapshot invariant.

Check the AX tree diff: a changed value, a new element, a new window, or the disappearance of the thing you just clicked (menus collapse after selection, buttons may become disabled, etc.). If nothing changed, the action likely failed silently — tell the user what you attempted and what you observed, don't paper over with "done" language. Agents that skip this step report success on silently-dropped actions — the single most common failure mode.

Recording trajectories

OpenClicky's default runtime does not expose set_recording, get_recording_state, or replay_trajectory. If the user asks to record, replay, or export a browser/app trajectory, stop and explain that this build cannot do it through Computer Use.

See RECORDING.md only as upstream reference material for a future runtime that explicitly exposes those tools.

Common error patterns

Error text	Meaning	Fix
No cached AX state for pid X window_id W	You either skipped get_window_state this turn, or passed a different window_id to the click than the one the snapshot cached against	Call get_window_state({pid: X, window_id: W}) first — the same window_id you intend to click in
Invalid element_index N for pid X window_id W	Index is stale or out of range	Re-run get_window_state with the same window_id, pick a fresh index from the new tree
window_id W belongs to pid P, not …	Passed a window_id that's owned by a different process	Use list_windows({pid: X}) to enumerate this pid's own windows
AX action AXPress failed with code …	Element doesn't support AXPress	Try show_menu, confirm, cancel, or pick
macOS system-alert beep on press_key with no visible change	Target window is minimized; Return / Space / Tab commits don't establish real renderer focus on minimized windows	AX-click a clickable equivalent (Go button, Submit button, checkbox) instead of pressing the key; see "Keyboard commits on minimized windows" under the Browser section
Accessibility permission not granted	TCC not granted	Stop; tell user to grant in System Settings
Screen Recording permission not granted	TCC not granted for capture	Affects screenshot and get_window_state (which always captures). Grant in System Settings — the driver can't operate without it

Things to avoid

• Never reuse an element_index across a re-snapshot of the same pid.
• Never translate screenshot pixels into a click unless the current OpenClicky tool descriptor explicitly documents that coordinate space. In the MCP lane, screenshots are for visual disambiguation and element_index is the primary action handle.
• Prefer AX over pixels in the MCP lane. Exhaust AX paths, command palettes, toolbar items, keyboard shortcuts, and page before using or reporting the need for an explicit pixel/foreground route.
• Never drive destructive actions (delete files, close unsaved documents, send messages, submit forms) without explicit user intent for that specific destructive step.
• Never launch apps autonomously; confirm with the user first unless their original request clearly implies the launch.

Example end-to-end task

User: "Open the Downloads folder in Finder."

1. launch_app({bundle_id: "com.apple.finder", urls: ["~/Downloads"]}) → {pid: 844, windows: [{window_id: 6123, title: "Downloads", ...}]}. Idempotent launch; plus Finder opens a background-safe window rooted at ~/Downloads via application(_:open:) — zero activation, no focus steal. The windows array lets you skip a list_windows hop.
2. get_window_state({pid: 844, window_id: 6123}) → verify an AXWindow whose title contains "Downloads" is present with a populated AX subtree (sidebar, list view, files).
3. Done.

If the user instead asks to navigate within an already-open Finder window, use the menu-bar flow from the "Navigating native menu bars" section above (click Go → pick a menu item → re-snapshot → click it).