arena

arena is a skill for Claude Code from J-StaR-Films-Studios/VibeCode-Protocol-Suite. It costs 58 tokens per session (1,186 once invoked), scanned A, a copy of arena, ISC.

A skill for running several parallel attempts at the same task, choosing a strong starting result, and combining useful parts from the others.

In plain words
What is it for?
Use it to compare alternative implementations or drafts and merge the best ideas into one result. It can be invoked with commands such as /arena or “arena this.”
Why use it?
It helps when one early approach could produce the wrong structure for a non-trivial artifact.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: mentions subagents.

Good fit Use it to compare alternative implementations or drafts and merge the best ideas into one result. It can be invoked with commands such as /arena or “arena this.”

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/j-star-films-studios/vibecode-protocol-suite/arena
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add J-StaR-Films-Studios/VibeCode-Protocol-Suite --skill arena
Clone the repo
git clone --depth 1 https://github.com/J-StaR-Films-Studios/VibeCode-Protocol-Suite

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for arena

README.md
[![agentmods](https://agentmods.dev/badge/skills/j-star-films-studios/vibecode-protocol-suite/arena/github.svg)](https://agentmods.dev/skills/j-star-films-studios/vibecode-protocol-suite/arena)
Your own site
<a href="https://agentmods.dev/skills/j-star-films-studios/vibecode-protocol-suite/arena"><img src="https://agentmods.dev/badge/skills/j-star-films-studios/vibecode-protocol-suite/arena/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for arena

Your own site · 80×15
<a href="https://agentmods.dev/skills/j-star-films-studios/vibecode-protocol-suite/arena"><img src="https://agentmods.dev/badge/skills/j-star-films-studios/vibecode-protocol-suite/arena.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,186 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00058 $0.01186
Opus 5 $0.00029 $0.00593
Sonnet 5 $0.00012 $0.00237
Haiku 4.5 $0.00006 $0.00119

Measured 10d ago against content hash a2241e8500a4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

arena scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to arena — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

assets/.agent/skills/agent-engineering/arena/SKILL.md · 72 lines

How it starts

The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Arena

Fan out N parallel attempts at the same task. Read every candidate end to end. Pick the strongest as the base. Graft the best ideas from the others into it. Verify the synthesized result.

Start

Open a todolist with one entry per phase before launching anything. The arena runs autonomously and the list keeps phases from silently disappearing.

  1. Frame
  2. Fan out
  3. Cross-judge
  4. Pick
  5. Graft
  6. Verify

Phase A: Frame

The N candidates will receive the same prompt, so the prompt is the contract. Get it right before spawning anything.

  1. State the artifact each candidate is producing.
  2. Derive the rubric. State what success looks like for this task, then turn it into 3-6 concrete gradeable criteria. Concrete: Adds a --dry-run flag that skips writes. Vague: code is correct. The rubric is the picker's tool in Phase D; candidates only see the task.
  3. Pick the runners. Use arena runners from ~/.cursor/rules/pstack-models.mdc when present. Otherwise default to one each on claude-fable-5-thinking-max, gpt-5.6-sol-max, grok-4.6-fast-xhigh, claude-opus-5-thinking-xhigh. Spawn more when the arena covers multiple design directions. Same model N times when the work is generation-bound rather than judgment-sensitive.
  4. Assign output paths. Each candidate writes to its own location (a git worktree where possible, otherwise /tmp/arena-<slug>/candidate-<n>/). N candidates writing to the same path is shared mutable state and fails the the separate-before-serializing-shared-state principle skill test.

Phase B: Fan out

Spawn all N subagents in one message with run_in_background: true, each with the task, the path to the shared grounding, its own output path, and instructions to produce both the artifact and a short rationale.

The rationale is mandatory. Without it, the parent cannot tell whether a candidate's structure is principled or accidental, which makes Phase E grafting unreliable. Each rationale names the alternatives the candidate considered and what it rejected.

Read the full file on GitHub · 72 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 72 lines · 58 tokens per session scan A a2241e8500a4

Subscribe to this mod's changes

arena is a skill published in the GitHub repository J-StaR-Films-Studios/VibeCode-Protocol-Suite (24 stars, last pushed 5d ago), licensed ISC. It adds 58 tokens to every session and 1,186 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to arena, differing in 0 lines, and is treated as a copy.

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