arena CLAUDE.md

A project instruction file that tells a coding agent which guidance to read first in the Arena repository. It directs the agent to choose between design work and changes to Arena itself.

In plain words
What is it for?
Use it when working in Arena to route design tasks to the design instructions and product or code changes to the main agent instructions.
Why use it?
It prevents the agent from starting on the wrong branch or following the wrong set of project instructions.

Instructions file

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.

agentmods
npx agentmods add instructions/dravensoft-dev/arena/claude-md
Clone the repo
git clone --depth 1 https://github.com/dravensoft-dev/arena
Per session 177 This file is loaded in full into every session.
When invoked 177 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.00177 $0.00177
Opus 5 $0.00088 $0.00088
Sonnet 5 $0.00035 $0.00035
Haiku 4.5 $0.00018 $0.00018

Measured 2d ago against content hash 0f57cbd16ed2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

arena CLAUDE.md 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 2d 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.

CLAUDE.md · 12 lines

What it actually says

CLAUDE.md

Two branches, and this file is neither. Pick one before you read anything else.

  • Building something with Arena, a screen, a prototype, a skin, an integration: skills/design/SKILL.md.
  • Changing Arena itself, a component, a token, a contract, a gate, a release: AGENTS.md.

This file carries no rule of its own. It exists because a harness that loads CLAUDE.md and nothing else would otherwise land on whichever branch this file happened to name, and landing on the wrong one is how a short question turns into a long read. Two routers that can disagree are worse than one, so both of the above are stated once, on the other side of their own link.

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. 2d ago First seen · 12 lines · 177 tokens per session scan A 0f57cbd16ed2

Subscribe to this mod's changes

arena CLAUDE.md is an instructions file published in the GitHub repository dravensoft-dev/arena (2 stars, last pushed 10d ago), licensed MIT. It adds 177 tokens to every session, about $0.0009 per session on Opus 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 2026-08-31.

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