# Mark Phelps (slim)

> Mark Phelps is creator and maintainer at Offscreen. Offscreen on Anchor Terminal, with grades, an about and public profiles.

- Full: https://www.anchorterminal.com/people/mark-phelps/index.md (~750 tokens) · this version ~480 tokens · JSON https://www.anchorterminal.com/people/mark-phelps/index.json · canonical https://www.anchorterminal.com/people/mark-phelps/
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-10-27
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

Creator and maintainer, Offscreen.

Mark Phelps builds Offscreen, which runs macOS UI tests and GUI apps for coding agents in throwaway virtual machines.

- LinkedIn: https://www.linkedin.com/in/markphelps1
- X: https://x.com/itsmarkphelps
- GitHub: https://github.com/markphelps

## What Mark builds

- [Offscreen](https://www.anchorterminal.com/tools/offscreen.md), graded B, 63.4/100, in Code execution sandboxes. Offscreen is an open-source macOS command-line tool, daemon and menu bar app that runs a coding agent's UI tests, iOS Simulator runs and GUI app launches in a fresh Tart virtual machine per job, away from the user's desktop. Creator and maintainer, Offscreen, founder, researched 2026-10-27.

## Questions

### Who is Mark Phelps?

Mark Phelps builds Offscreen, which runs macOS UI tests and GUI apps for coding agents in throwaway virtual machines.

### What does Mark Phelps (independent) make?

Anchor Terminal lists Offscreen from Mark Phelps (independent).

### How are Mark's tools graded?

Offscreen is graded B, 63.4 out of 100, on Anchor Terminal's benchmark, which scores every listing against the same checklist.

## Sources

- https://raw.githubusercontent.com/markphelps/offscreen/main/README.md
- https://raw.githubusercontent.com/markphelps/offscreen/main/LICENSE
- https://markphelps.me

These are the people building the tools we list, named for their public role in the company or project behind a listing, from public pages, with the date it was researched.