The Duel (Face Off) skill

---
name: duel
description: Have an OpenAI model challenge Claude's answer, then defend or revise it through a short evidence-led debate. Use for "duel this with ChatGPT", "face off this answer", or an explicit request for a second model to critique an answer.
---

# Duel — Face Off

Turn a questionable answer into a stronger one by exchanging actual critiques with
an OpenAI model. You are the defender and final editor in the current Claude Code
session. The bundled helper calls the critic through the OpenAI API. Never write
both sides yourself and describe it as two models debating.

## Start with the user's question

- `/duel` uses the last substantive request and the answer the user wants challenged.
- `/duel <task>` drafts an initial answer to that task, then debates it.
- `/duel --quick` allows one critique/revision exchange.
- `/duel --rounds N` allows 1–3 exchanges; default maximum is 3.
- `/duel --model MODEL` selects the critic. Otherwise use `DUEL_OPENAI_MODEL`, then
  the helper's default. `/duel --manual` uses critiques the user supplies from a
  separate model instead of the API.

Interpret flags as data. Never interpolate raw user arguments into a shell command.
Ask a short clarifying question only if the target request or answer is ambiguous.
Do not broaden the original task. A debate about an action does not authorize
performing that action.

An explicit request to use Duel authorizes its ordinary bounded critique calls.
If you merely suggest Duel during another task, get agreement before sending that
task to another provider. Keep normal tool permissions in force. Briefly tell the
user which model will receive the prepared question, answer, and relevant context,
and the maximum number of calls. OpenAI API usage is billed separately.

## Prepare the exchange

1. Run `python3 "${CLAUDE_SKILL_DIR}/scripts/duel.py" check` (add `--model` when the
   user selected one). It checks configuration
   without making a network request or printing the API key. A successful check
   does not prove the key is valid or the model is accessible.
2. If configuration is missing, explain how to set `OPENAI_API_KEY` in the terminal
   environment that launches Claude Code, or offer manual mode. Never ask the user
   to paste a key into chat, read credential stores, or quietly substitute a
   simulated critic. A different model requires the user's choice if the configured
   model fails.
3. Create a unique run folder under `.duel/` in the working project, with private
   permissions where supported. Store only the selected task, answer, necessary
   context, and debate artifacts there. These can be sensitive: do not commit them
   or change the project's ignore rules without authorization. If the project
   cannot be written, use a temporary run folder and report its location.
4. Identify the material claims in the initial answer. Assign stable IDs such as
   C1, C2, C3. Capture constraints and user-supplied facts separately from guesses.
   Include only relevant content authorized for this task, with credentials removed.
   Do not collect the whole conversation or scan unrelated project files.

Read [references/protocol.md](references/protocol.md) for the exact packet and file
formats before the first exchange. Write JSON with a file-writing tool or a JSON
serializer. Use distinct filenames for each round and do not overwrite prior runs.

## Run the debate