The Arena skill

When Claude keeps giving you bad answers, make 100 versions of it fight to the death. One Claude Code skill. Free, MIT, no signup, no API key, nothing to connect.

You use it when you are not happy with what Claude gave you. Instead of asking again and again, /arena spins up 100 sub-agents and gives every one of them the exact same task, word for word. Each one gets a different strategy card: a way of reasoning, a workflow and a strategy, so each one attacks the task differently. Then they pair off. Each attacks the other's solution, each defends and revises its own, and a judge scores the match on a written rubric. The loser is out. 100 becomes 50, then 25, 13, 7, 4, 2, 1.

What comes back is the one solution that survived, the attacks it beat on the way, and how many rounds it took.

It never touches your files. Every sub-agent writes inside .arena/. The winning answer comes back to you, and using it is your call.

Install

Paste this into Claude:

https://github.com/Jakeschincariol/arena-skill

Install this skill, then confirm /arena works.

Or copy the folder yourself, in Claude Code:

git clone https://github.com/Jakeschincariol/arena-skill.git
cp -r arena-skill/skills/arena ~/.claude/skills/

Or as a plugin:

/plugin marketplace add Jakeschincariol/arena-skill
/plugin install arena-skill@arena-skill

Claude Code namespaces plugin skills, so installed as a plugin it shows up as /arena-skill:arena. Copy the folder instead if you want plain /arena. Project-local instead of global: copy the same folder into your repo's .claude/skills/.

It needs Claude Code, because it spawns sub-agents with the Agent tool, and Python 3.8 or newer. Nothing to pip install.

Use it

/arena
/arena --quick write the headline for our pricing page
/arena --agents 32 fix the flaky test in tests/test_api.py
/arena --seed 7 plan my launch week, I have 6 hours a day

On its own, /arena takes your last request as the task and the answer you did not like as the one to beat. Claude can also reach for it without the slash, when you say something like "that's a bad answer, make them compete". When it starts itself like that, it asks before it spends anything.

flag	what it does
--agents N	N competitors. Default 100.
--quick	16 competitors. The everyday setting.
--seed S	Same seed, same cards and same bracket. Default random, and recorded.
--wave W	Sub-agents per wave. Default 10. Only raise it if you raised Claude Code's limit.

How it works