Muse for Mac 'Endo' teardown

# Muse "Endo" teardown — Meta's desktop agent has computer‑use built in, gated off

A static teardown of Meta's **Muse** desktop app for macOS (codename **"Endo"**, bundle
`com.meta.endo`, v1.0). The finished implementation for a computer‑using agent — seeing the
screen, clicking, typing, running programs, driving a browser — ships in the public build but is
switched **off** by server‑delivered feature flags.

> **Found in code, not shipped.** Everything here was read out of the released binary and its
> Meta‑served config on a single Mac. Flag names, gates, and plans change; some features never
> leave the lab. This is observation and commentary, not confirmation from Meta. No app binary is
> redistributed here, and no credentials are published.

**Read the illustrated report:** [`report/endo-edition-2026-09-17.pdf`](report/endo-edition-2026-09-17.pdf)

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## Subject

| | |
|---|---|
| App | Muse (Meta) for macOS, v1.0 |
| Codename / bundle | Endo / `com.meta.endo` |
| Binary | Mach‑O arm64, ~17 MB, Swift + AppKit + SwiftUI |
| Signature | Developer ID Application: Meta Platforms, Inc. (notarized) |
| Updater | Sparkle |

## The five gated capability flags

Muse fetches its feature gates from a Meta config (`endo-values-public…json`, in the app's cache)
and **re‑downloads them on every launch** — editing them locally is overwritten within seconds.
Five booleans in the `hatch_desktop` namespace decide whether the agent can operate the machine,
and all five arrive `false`:

| Flag | Value | Governs |
|---|---|---|
| `hatch_desktop:enable_computer_control` | `false` | Clicking / typing / controlling the Mac |
| `hatch_desktop:endo_enable_screen_recording` | `false` | The agent seeing the screen |
| `hatch_desktop:enable_browser_automation` | `false` | Driving a browser |
| `hatch_desktop:endo_system_run_sandbox_enabled` | `false` | Sandboxed program execution |
| `hatch_desktop:endo_enable_computer_use_onboarding` | `false` | First‑run "let Muse control your Mac" flow |

## What the binary already contains behind those flags

- **Screen vision** — links Apple's `ScreenCaptureKit` (`SCShareableContent`, `SCStreamConfiguration`),
  calls `CGPreflightScreenCaptureAccess` / `CGRequestScreenCaptureAccess`, and carries an on‑screen
  computer‑use overlay + an accessibility‑first click mode (`_showComputerUseOverlay`,
  `_preferAXForComputerUseClicks`, `[ComputerUs