Codex Computer Use Cursor Reverse Engineering

This document records the cursor-specific evidence used by Maka's overlay. It keeps confirmed native facts separate from implementation inference.

Inspected artifact

App: ~/.codex/computer-use/Codex Computer Use.app
Executable: Contents/MacOS/SkyComputerUseService
Bundle identifier: com.openai.sky.CUAService
Signed: 2026-07-16
SHA-256: 44320516c4c400fb5459b203498c78e4af318b0096464f16c4445a47f2b8b8f4

Confirmed style architecture

The current native binary contains:

ComputerUseCursor
ComputerUseCursor.Style
SoftwareCursorStyle
FogCursorStyle
FogCursorViewModel
AgentCursor
CursorView

SoftwareCursor is a separate 200x230 asset and is not the soft cursor shown by the current Fog style. FogCursorStyle hosts CursorView in an NSHostingView. Its hotspot getter returns half the hosting view size, so the action coordinate is the view center rather than the arrow tip.

Exact AgentCursor geometry

AgentCursor.path(in:) builds a normalized path:

Move to (0.00599w, 0.15864h).
Curve to (0.15158w, 0.00627h) with controls (-0.02364w, 0.06456h) and (0.06169w, -0.02474h).
Line to (0.87634w, 0.25652h).
Curve to (0.88794w, 0.48095h) with controls (0.97594w, 0.29096h) and (0.98340w, 0.43547h).
Line to (0.59343w, 0.62108h).
Line to (0.45955w, 0.92925h).
Curve to (0.24510w, 0.91717h) with controls (0.41611w, 1.02925h) and (0.27801w, 1.02146h).
Line back to the start and close.

The observed Retina screenshot has an approximately 29x30 physical-pixel strong silhouette, consistent with a 14x14 logical-point path plus stroke.

Exact MotionConfiguration.live values

Field	Value
clickAngle	-44 degrees
candidateCount	20
boundsMargin	20
startHandle	0.41960295031576633
endpointHandle	0.15
arcSize	0.27655231880642772
arcFlow	0.5783555327868779
straightPathDistanceThreshold	10
springResponseScaler	0.9
springResponseMin	0.12
springResponseMax	2.2
springDampingFraction	0.9
scootDistanceThreshold	196
scootPositionResponse	0.24
scootPositionDampingFraction	0.84
scootPositionSettleVelocity	12
scootAxisResponse	0.07
scootAxisDampingFraction	0.82
scootBaseRotationResponse	0.09
scootBaseRotationDampingFraction	0.86
scootStretchResponse	0.095
scootStretchDampingFraction	0.72
scootStretchMin	0
scootStretchPivotX	0.5
scootStretchXAmount	0.38
scootSquashYAmount	0.18
scootRotationResponse	0.055
scootRotationDampingFraction	0.76
scootRotationMax	76 degrees
terminalTangentBlendStart	0.99

The window stores separate animation objects for motion progress, scoot position, base rotation, axis, stretch, and rotation offset. Style state exposes velocity, pressed/activity/attached state, angle, X stretch, overall stretch, pivot, stretch angle, and tilt angle.

Window and lifecycle findings

The virtual cursor is lazily created and retained for reuse.
orderOut() hides it without clearing the controller field.
The overlay is associated with a target window/application and can remain behind an unrelated foreground app. It is not a global screen-saver-level overlay.
move accepts target point, target window ID, relative-window mode, next-interaction timing, animation, fade-in, and delegate flags.
Successful virtual-cursor press still precedes the ordinary synthetic CG event path; the cursor is a visual interaction layer, not a click backend.

Maka implementation boundary

Maka copies the exact glyph, hotspot convention, thresholds, and recovered configuration constants. The binary's candidate path scoring function is stripped, so Maka uses a deterministic 20-candidate cubic planner with the exact handle and arc constants. This is a structural reproduction, not a claim of instruction-for-instruction equivalence.

Visual validation

Validate against the live overlay, not checked-in screenshots:

Render the same built Canvas engine on both light and dark surfaces and confirm the soft fog silhouette and center hotspot.
Sample one long move and confirm the curved path, movement-axis stretch and rotation, and terminal settle.

PR visual evidence belongs on the pull request (or issue), not under docs/.