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-change-spec)<a href="https://agentmods.dev/skills/appsvortex/arness/arn-infra-change-spec"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-infra-change-spec/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-change-spec"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-infra-change-spec.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 | $0.00124 | $0.02781 |
| Opus 5.5 | $0.00050 | $0.01112 |
| Sonnet 5.5 | $0.00025 | $0.00556 |
| Haiku 4.5 | $0.00012 | $0.00278 |
Grade A, and why
arn-infra-change-spec 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 — 254 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Arness Infra Change Spec
Develop an infrastructure change idea into a well-formed specification through iterative conversation, aided by the arn-infra-request-analyzer and arn-infra-cost-analyst agents. This is a conversational skill that runs in normal conversation (NOT plan mode). The primary artifact is an infrastructure change specification written to the project's infra specs directory that captures affected resources, blast radius, environment scope, rollback requirements, compliance constraints, and cost impact. The spec then informs plan creation via /arn-infra-change-plan.
This skill supports two entry paths:
- Fresh: Guide the user through an iterative conversation to develop the change from scratch
- Upgrade from interactive: Accept existing IaC artifacts or resource manifests produced by interactive skills (define, containerize, deploy) and build a structured spec around them
Pipeline position: arn-infra-init -> arn-infra-wizard (Full Pipeline) -> [arn-infra-change-spec] -> arn-infra-change-plan -> arn-infra-save-plan -> arn-infra-execute-change -> arn-infra-review-change -> arn-infra-document-change
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.
Check the Deferred field. If Deferred: yes, inform the user: "Infrastructure is in deferred mode. Change specification is not available until infrastructure is fully configured. Run /arn-infra-assess to un-defer." Stop.
Extract:
- Infra specs directory -- path where INFRA_CHANGE_*.md specs are stored (default:
.arness/infra-specs) - 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. - Providers -- which cloud providers are configured
- Environments -- which environments exist and their promotion order
- Cost threshold -- budget threshold for cost impact warnings
What ships with it
2 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 · 254 lines · 124 tokens per session scan A 650b11729902
arn-infra-change-spec is a skill published in the GitHub repository AppsVortex/arness (33 stars, last pushed yesterday), licensed MIT. It adds 124 tokens to every session and 2,781 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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