Reverse-Engineered Accessibility Tree Desktop Control Tool

aigclink · x · 2026-07-14

A developer reverse-engineered Codex's Computer Use to build pi-computer-use, a tool capable of operating macOS / Windows desktop software.

Instead of guessing button coordinates from screenshots like typical computer use tools, its core approach is ax-first: it reads the app's accessibility tree and platform accessibility APIs to directly extract UI elements like buttons, text, and controls before executing click / type / scroll commands. Vision is only used as a fallback for supported models. macOS requires a helper app with Accessibility + Screen Recording permissions, while Windows interfaces directly with the platform's accessibility API.

The author notes that this isn't meant to replace app APIs or MCP. Direct connections should always be preferred when available; computer use serves as an ecosystem gap-filler, empowering agents to operate legacy software that lacks APIs.

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