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.
npx agentmods add skills/appsvortex/arness/arn-code-ensure-confignpx skills add AppsVortex/arness --skill arn-code-ensure-configgit clone --depth 1 https://github.com/AppsVortex/arnessWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00133 | $0.00368 |
| Opus 5 | $0.00067 | $0.00184 |
| Sonnet 5 | $0.00027 | $0.00074 |
| Haiku 4.5 | $0.00013 | $0.00037 |
Grade A, and why
arn-code-ensure-config 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.
What it actually says
Arness Code Ensure Config
Verify and establish Arness Code configuration for the current project. This skill guarantees that a valid user profile and ## Arness section exist before any Arness Code workflow proceeds. It runs automatically as Step 0 of all entry-point skills via a hash-based fast-path cache.
Entry points should NOT read this SKILL.md directly. They should read ${CLAUDE_PLUGIN_ROOT}/skills/arn-code-ensure-config/references/step-0-fast-path.md, which runs the cache-check shell script and only falls through to the full validation when needed. This indirection is what saves ~95% of ensure-config token cost.
When invoked DIRECTLY (rare — typically via /arn-code-ensure-config), this skill bypasses the cache and runs the full validation flow.
Workflow
Read ${CLAUDE_PLUGIN_ROOT}/skills/arn-code-ensure-config/references/ensure-config.md and follow its instructions (Layers 1–3, then Layer 4 cache write).
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 2d ago First seen · 25 lines · 133 tokens per session scan A decbda8abd6b
arn-code-ensure-config is a skill published in the GitHub repository AppsVortex/arness (33 stars, last pushed 1mo ago), licensed MIT. It adds 133 tokens to every session and 368 once invoked, about $0.0007 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 2026-08-30.
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