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-infraWrote 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-infra-discover)<a href="https://agentmods.dev/skills/appsvortex/arness/arn-infra-discover"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-infra-discover/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-infra-discover"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-infra-discover.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 | $0.00121 | $0.02387 |
| Opus 5.5 | $0.00048 | $0.00955 |
| Sonnet 5.5 | $0.00024 | $0.00477 |
| Haiku 4.5 | $0.00012 | $0.00239 |
Grade A, and why
arn-infra-discover 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.
How it starts
The opening of the file, as written. The whole thing — 209 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Arness Infra Discover
Proactively audit installed infrastructure tools (MCPs, CLIs, Claude Code plugins), check authentication state, search online for new official tools, generate installation recommendations, and produce a tooling manifest. This is the second step after arn-infra-init -- it ensures the user has the right tools configured before generating infrastructure code.
This skill is proactive: it does not just check what is installed, but actively recommends what should be installed based on the user's provider configuration. It distinguishes between official (first-party from the cloud provider) and community tools, prioritizing official tools in recommendations.
Prerequisites
Read ## Arness from the project's CLAUDE.md. If no ## Arness section exists or Arness Infra fields are missing, inform the user: "Arness Infra is not configured for this project yet. Run /arn-infra-wizard to get started — it will set everything up automatically." Do not proceed without it.
Extract:
- Providers -- which providers to discover tools for
- Default IaC tool -- which IaC tooling to check
- Experience level -- derived from user profile. Read
~/.arness/user-profile.yaml(or.claude/arness-profile.local.mdif it exists — project override takes precedence). Apply the experience derivation mapping from${CLAUDE_PLUGIN_ROOT}/skills/arn-infra-ensure-config/references/experience-derivation.md. If no profile exists, check for legacyExperience levelin## Arnessas fallback. - Tooling manifest -- path where the manifest will be written
Workflow
Phase A: Detect Installed Tools
For each provider in the Providers list, check what is already installed.
Read the local override or plugin default for
mcp-registry.md. Read the local override or plugin default forcli-registry.md. Read the local override or plugin default forplugin-registry.md.
The three registry files above are evolving references (read from the user's local .arness/infra-references/ override if it exists, otherwise from the plugin default). The tooling manifest schema referenced in Phase D is a static reference always read directly from the plugin.
What ships with it
4 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.
- yesterday First seen · 209 lines · 121 tokens per session scan A 95b7bb299c26
arn-infra-discover is a skill published in the GitHub repository AppsVortex/arness (33 stars, last pushed yesterday), licensed MIT. It adds 121 tokens to every session and 2,387 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 2026-10-25.
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