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Agents · Checked on 2026-10-03, with codex-cli 0.160

DMN for Codex

Codex and Claude Code each start every session from scratch, and neither knows what the other found. DMN gives both the same project notes, the same code search and claims on the files they're editing.

What Codex gets

  • Notes from every agent. What Claude Code saved yesterday, Codex reads today.
  • A briefing at session start. Your rules first, then the newest notes, each with its age.
  • Code search in one call. The matching code comes back, not a list of files to read.
  • Claims on files. It sees which files Claude Code is editing, and works around them.

An example

In the demo, Codex asks about Stripe and gets back a note Claude Code saved two days earlier: the webhook must read the raw request body. So it adds checkout without breaking the webhook.

Set it up

In DMN, start Codex from + agent in the Fleet panel. Its panes get the briefing on every launch. For Codex in your own terminal:

  1. Install DMN

    From the download page. No account.

  2. Add the skill

    Writes ~/.codex/skills/dmn/SKILL.md, which teaches Codex the dmn command line. With --project, it goes in the repository's .agents/skills instead. 

    dmn skill-init --apply --agent codex

  3. Add the briefing

    Adds a session-start hook to Codex's hooks.json and marks it trusted in its config.toml, so Codex runs it without asking. Both live in $CODEX_HOME, which is ~/.codex unless you've moved it. 

    dmn hook-init --apply --agent codex

Leave out --apply to see what a command would change first. Prefer MCP tools to a skill? dmn mcp-init --apply --agent codex adds DMN's MCP server to Codex's config.toml. To check or undo any of it, see Connect your agents.

Questions

Does DMN use my Codex subscription?

Codex keeps using your own login, as it does without DMN. DMN doesn't sell AI.

Can Codex and Claude Code edit the same checkout?

Yes. Each claims the files it's about to change, and the other sees the claim before touching them. Claims are advisory: they never block a write. For full isolation, start one of them in its own git worktree from DMN's spawn sheet.

Can Codex and Claude Code share context without DMN?

Partly: one AGENTS.md both read, or a hand-off file one writes and the other reads. Share context between Claude Code and Codex covers both, and where they stop. For what Codex keeps on its own, see Codex's memory between sessions.

Will Codex use fewer tokens?

We haven't measured it. The benchmarks ran Claude Code; other agents may gain more or less.

See Codex and Claude Code together

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