Build with both

For a card where you are unsure of the approach, Build with both has Claude and Codex each build it in their own copy of the repository.

Start it

On a card that is Ready to start, press Build with both in the Now box. The sheet says: “Claude and Codex each build this card in their own copy of the repository; the Challenger compares the two and you pick one. Choose each build’s model — for this card only.” Each build’s model starts from the Builder row (From the Builder row: CLI default); a model you change reads Changed for this card. Press Start both builds.

While they build

The card says Building with both, with the Builder Claude and Codex. Under Now there is one card per build, with its own words (Building, Waiting for you), the model, how long ago it started, Open session and Build done. The sidebar lists both sessions, for example Card · Round half up · Claude’s build. Press Build done on each when it’s finished.

Compare and pick

When both are done and their checks have run, the Challenger compares them against the card. The card says Pick one of the two builds, and above the two builds: The Challenger recommends Claude’s build (or Codex’s), its reasons, and Judged by Codex (or Claude). Each build shows:

its state, for example Done · no checks set up, and the model it ran on;
the files it changed, for example 3 files changed · +36 −1, and a summary;
The Challenger found no problems in it. or The Challenger’s 2 findings;
Open the diff and Pick Claude’s build or Pick Codex’s build.

The recommended one is tagged Recommended. When only one build finished, it reads Only result. The build you pick becomes the card’s, and its Build done starts the full review. The other build is set aside; its branch is kept. Stop building with both… ends it without a pick.