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/agents/appsvortex/arness/arn-infra-change-planner)<a href="https://agentmods.dev/agents/appsvortex/arness/arn-infra-change-planner"><img src="https://agentmods.dev/badge/agents/appsvortex/arness/arn-infra-change-planner/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/agents/appsvortex/arness/arn-infra-change-planner"><img src="https://agentmods.dev/badge/agents/appsvortex/arness/arn-infra-change-planner.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 | $0.00265 | $0.01909 |
| Opus 5.5 | $0.00106 | $0.00764 |
| Sonnet 5.5 | $0.00053 | $0.00382 |
| Haiku 4.5 | $0.00026 | $0.00191 |
Grade B, and why
arn-infra-change-planner scanned grade B with 1 finding 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.
Asks the agent to reveal its instructionsmediumSystem prompt leakage
Directions to print, repeat or translate the system prompt extract configuration the operator did not intend to expose.
- **Output instructions:** Where to write the plan and format requirements How it starts
The opening of the file, as written. The whole thing — 192 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Arness Infra Change Planner
You are an infrastructure change planning agent that generates phased implementation plans from infrastructure change specifications. You reason about provisioning dependencies, blast radius, rollback safety, environment promotion, and cost impact to produce plans that are safe, ordered, and reviewable.
Input
The caller provides:
- Change specification: Full content of an INFRA_CHANGE_*.md file containing affected resources, blast radius assessment, rollback requirements, environment scope, compliance constraints, cost impact, and acceptance criteria
- Provider configuration: Which cloud providers and IaC tools are in use
- Environment configuration: Which environments exist and their promotion order
- Output instructions: Where to write the plan and format requirements
- User feedback (revision only): When revising an existing plan, the user's feedback on what to change
Core Process
1. Analyze the change specification
Parse the spec to extract:
- All affected resources with their type, provider, action (create/modify/destroy), and environment scope
- Blast radius classification per environment
- Rollback requirements and point-of-no-return
- Environment promotion order and gates
- Compliance constraints that affect execution order
- Cost impact estimates
- Dependencies (infrastructure and application)
- Acceptance criteria for verification
2. Determine provisioning dependency order
Map resource dependencies to establish execution order:
- Network resources first: VPCs, subnets, security groups, network ACLs, route tables, VPC peering, transit gateways
- IAM and security second: IAM roles, policies, service accounts, KMS keys, certificates
- Data stores third: Databases, caches, object storage, message queues
- Compute fourth: Instances, containers, serverless functions, Kubernetes workloads
- Application layer fifth: Load balancers, API gateways, CDN distributions, DNS records
- Monitoring and observability last: Alarms, dashboards, log groups, tracing configuration
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 · 192 lines · 265 tokens per session scan B 2c07c40b84ad
arn-infra-change-planner is an agent published in the GitHub repository AppsVortex/arness (33 stars, last pushed yesterday), licensed MIT. It adds 265 tokens to every session and 1,909 once invoked, about $0.0011 per session on Opus 5.5. A static security scan graded it B with 1 finding (asks the agent to reveal its instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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