arena

arena is a skill for Claude Code, Codex from chhoumann/t3-pstack. It costs 58 tokens per session (1,419 once invoked), scanned A, original, MIT.

A workflow that runs several independent attempts at the same task, compares them against agreed criteria, and combines the best parts into one result. It then verifies the combined result.

In plain words
What is it for?
Use it for non-trivial artifacts or solutions where comparing multiple candidate approaches is worthwhile.
Why use it?
It reduces the chance that the first approach locks in a poor design or misses useful alternatives.

Skill for Claude CodeCodex

Written for Claude Code and Codex: disable-model-invocation in frontmatter, but also reads $CODEX_HOME. Also seen: reads .claude/ paths; mentions subagents; mentions Claude Code.

Part of the t3-pstack plugin — 62 skills, 4 agents, 1 hook shipped together

Good fit Use it for non-trivial artifacts or solutions where comparing multiple candidate approaches is worthwhile.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/chhoumann/t3-pstack/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 chhoumann/t3-pstack --skill arena
Clone the repo
git clone --depth 1 https://github.com/chhoumann/t3-pstack

Made for: Claude Code, Codex.

Or install t3-pstack, the plugin that ships this one along with the rest of its 62 skills, 4 agents, 1 hook.

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/chhoumann/t3-pstack/arena/github.svg)](https://agentmods.dev/skills/chhoumann/t3-pstack/arena)
Your own site
<a href="https://agentmods.dev/skills/chhoumann/t3-pstack/arena"><img src="https://agentmods.dev/badge/skills/chhoumann/t3-pstack/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/chhoumann/t3-pstack/arena"><img src="https://agentmods.dev/badge/skills/chhoumann/t3-pstack/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 1,419 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 original No closer match found 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 $0.01419
Opus 5.5 $0.00023 $0.00568
Sonnet 5.5 $0.00012 $0.00284
Haiku 4.5 $0.00006 $0.00142

Measured yesterday against content hash 5d4a35f8e673, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, 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 yesterday.

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

Copies of this mod

1 near-identical copy found in the catalogue:

  • chimera — 86% identical, 65 lines differ
plugins/pstack/skills/arena/SKILL.md · 56 lines

How it starts

The opening of the file, as written. The whole thing — 56 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Arena

Open a todolist with one entry per phase (Frame, Fan out, Cross-judge, Pick, Graft, Verify) before launching anything.

Phase A: Frame

Every candidate gets the same prompt, so the prompt is the contract.

  1. State the artifact each candidate is producing.
  2. Derive the rubric, 3-6 concrete gradeable criteria for what success looks like on this task. It is the picker's tool in Phase D. Candidates only see the task.
  3. Pick the runners. Use the arena runners line in the model sheet. If the sheet or that line is missing, run one each on the defaults in Models. An auto or inherit-parent entry in this line or the cross-judge line means the parent model, so omit target for it. If delegate_task rejects a configured entry, run that seat on another target of the same family from orchestrator_capabilities and say so. A model's family is the first segment of its ID's last / part, such as claude, gpt, or grok, whatever provider instance serves it. With no family match, use the first arena runners default in Models. If it rejects a default, use another target of the same family from orchestrator_capabilities. Spawn more runners when the arena covers multiple design directions. Use the same model N times when the work is generation-bound rather than judgment-sensitive. Pick each subagent's reasoning level and fast or standard speed for the job, per the Subagents section of the poteto-mode skill.
  4. Give each candidate its own output location (a git worktree where possible, otherwise /tmp/arena-<slug>/candidate-<n>/), per the separate-before-serializing-shared-state principle skill.

Phase B: Fan out

Spawn all N subagents in one message with mode: "async", each with the task, the path to the shared grounding, its own output path, and instructions to produce the artifact and a short rationale naming the alternatives it considered and what it rejected.

If a candidate produces no output, proceed with N-1 and note the dropout.

Read the full file on GitHub · 56 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. yesterday Changed · -7 lines 5d4a35f8e673
  2. 3d ago First seen · 63 lines · 58 tokens per session scan A efa3d2e28afe

Subscribe to this mod's changes

arena is a skill published in the GitHub repository chhoumann/t3-pstack (190 stars, last pushed yesterday), licensed MIT. It adds 58 tokens to every session and 1,419 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-13.

Related

Other skills, from other repositories

local-ai-agents

Build local-first AI agents that run entirely on a developer workstation with Microsoft Foundry Local and Qwen function-calling models. Covers Small Language Models (SLMs), the OpenAI-compatible local endpoint, sandboxed local tools, local RAG with Chroma, local MCP servers, hybrid cloud/local routing, and the…

microsoft/ai-agents-for-beginners · 200 tokens

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

next-cache-components-adoption

Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…

vercel/next.js · 95 tokens

chat-pet-sprite-creation

Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.

microsoft/vscode · 53 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens

insight-error-page

Write or audit an insight-kind error page for the Next.js dev overlay. Use when creating a new errors/ .mdx page, auditing an existing one, or checking that a page matches the framework fix cards. Covers page structure, title alignment, FixCard cards with Copy prompt button, code snippets, terminology verification…

vercel/next.js · 83 tokens