Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add AppsVortex/arness/plugin install arn-codeWrote 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.
[](https://agentmods.dev/skills/appsvortex/arness/arn-code-ensure-config)<a href="https://agentmods.dev/skills/appsvortex/arness/arn-code-ensure-config"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-code-ensure-config/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.
<a href="https://agentmods.dev/skills/appsvortex/arness/arn-code-ensure-config"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-code-ensure-config.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00133 | $0.00368 |
| Opus 5.5 | $0.00053 | $0.00147 |
| Sonnet 5.5 | $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 1mo 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.
- 1mo 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 2mo ago), licensed MIT. It adds 133 tokens to every session and 368 once invoked, about $0.0005 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 2026-08-30.
Other skills, from other repositories
pulumi-component
Guide for authoring Pulumi ComponentResource classes. Use when creating reusable infrastructure components, designing component interfaces, setting up multi-language support, or distributing component packages.
pulumi-migrate-from-discovered-stack
Migrate a CloudFormation or ARM stack into a Pulumi stack, sourced from a stack that Pulumi Cloud's Discovery feature has already found and exposed via the discovered-stacks API. Load this skill when the user has a discovered stack in Pulumi Cloud and wants to bring its resources under Pulumi management. Do NOT load…
pulumi-overview
Use this skill for any task that creates, modifies, inspects, or destroys cloud infrastructure or SaaS configuration, from one-off CLI operations to full multi-resource projects, across providers in the Pulumi ecosystem. A typical project spans many providers (AWS or Azure or GCP, Kubernetes, Cloudflare, Auth0…
provider-upgrade
Upgrade any Pulumi provider to a newer version and reconcile the resulting diff. Use when users want to upgrade or update a provider (including editing package.json, requirements.txt, pyproject.toml, go.mod, or Pulumi.yaml to bump a provider SDK), check for breaking changes before or during an upgrade, fix resources…
pulumi-best-practices
Load when the user is writing, reviewing, or debugging Pulumi TypeScript/Python programs; asks about Output or apply() usage; wants to create ComponentResource classes; needs to refactor resources without destroying them (aliases); is setting up secrets or config; or is configuring a pulumi preview/up CI workflow.…
pulumi-cdk-to-pulumi
Load this skill when a user wants to migrate, convert, port, translate, or move an AWS CDK application (including CDK stacks, constructs, or CloudFormation-synthesized templates) to Pulumi. Phrases such as "convert CDK to Pulumi", "migrate CDK app", "port CDK stacks", "replace CDK with Pulumi", "stop using CDK". Do…