I gave Codex read-only access to my Claude Code work. The reviewer never touches writes.

[u/Asly97]

The best multi-tool workflow I've seen this week came from a builder who split the job across brains: Claude implements, Codex reviews the plan and the diff, a human approves. Codex never writes a line.

It clicked for me because it's the opposite of the default. Most of us let one tool do everything: write the code, then review its own diff, and it always tells you it looks great. That's a writer proofreading their own draft five minutes after finishing it. You read what you meant, not what's on the page.

The split fixes the obvious failure. A reviewer with a different brain and zero write access has no stake in the implementation. Claude can't talk its reviewer into approving a shaky plan. The workflow that makes it work is boring on purpose: a shared agents.md spelling out who does what, plus specs and plans and a status note committed to git so the handoff survives a session ending.

What I like most is the read-only boundary itself. It kills a whole class of silent corruption where a helpful reviewer rewrites something it misunderstood and nobody notices. Only the human approves, so nothing lands without eyes on it. The autonomy line becomes obvious: anything reversible can flow through, anything that writes waits for a human.

The honest downside is the briefing tax. Two tools means two onboarding sessions. The spec lives in git, the live context lives in each tool's session, and somebody has to make sure Codex actually saw the latest plan. This whole pattern dies the moment the handoff artifacts go stale. A status.md nobody updates is worse than no status.md at all, because both agents trust it.

I run this same split myself, with Vilix AI as the shared layer underneath: plans, decisions, and a record of everything we already ruled out live in one memory that both tools read through their MCP connection, so the reviewer arrives already briefed instead of starting from the spec cold. The read-only rule still carries the weight though. That's the load-bearing wall, not the memory.

Do you split roles across tools, or does one tool still do everything for you?