Zombie NAT Gateway Detector

Zombie NAT Gateway Detector is an agent for Claude Code from Cletrics/finops-agents. It costs 51 tokens per session (698 once invoked), scanned A, original, MIT.

A specialist for finding underused network address translation gateways in public clouds. These gateways let private resources reach external networks but can keep charging hourly even when they carry little traffic.

In plain words
What is it for?
Use it to inspect AWS NAT Gateways, Google Cloud NAT, and Azure NAT Gateways, identify likely waste, assess consolidation, and review possible deletions.
Why use it?
It helps uncover cloud infrastructure that costs money despite doing very little work. It also considers hidden uses, replacements such as VPC endpoints, and the reliability cost of consolidating gateways.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: mentions subagents; positional $N argument.

Good fit Use it to inspect AWS NAT Gateways, Google Cloud NAT, and Azure NAT Gateways, identify likely waste, assess consolidation, and review possible deletions.

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Install with agentmods
npx agentmods add agents/cletrics/finops-agents/zombie-nat-gateway-detector
Install

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.

Clone the repo
git clone --depth 1 https://github.com/Cletrics/finops-agents

Made for: Claude Code.

Wrote 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.

agentmods badge for Zombie NAT Gateway Detector

README.md
[![agentmods](https://agentmods.dev/badge/agents/cletrics/finops-agents/zombie-nat-gateway-detector/github.svg)](https://agentmods.dev/agents/cletrics/finops-agents/zombie-nat-gateway-detector)
Your own site
<a href="https://agentmods.dev/agents/cletrics/finops-agents/zombie-nat-gateway-detector"><img src="https://agentmods.dev/badge/agents/cletrics/finops-agents/zombie-nat-gateway-detector/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.

agentmods 80×15 button for Zombie NAT Gateway Detector

Your own site · 80×15
<a href="https://agentmods.dev/agents/cletrics/finops-agents/zombie-nat-gateway-detector"><img src="https://agentmods.dev/badge/agents/cletrics/finops-agents/zombie-nat-gateway-detector.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 51 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 698 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00051 $0.00698
Opus 5 $0.00026 $0.00349
Sonnet 5 $0.00010 $0.00140
Haiku 4.5 $0.00005 $0.00070

Measured 5d ago against content hash 0118c3aad5e9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

Zombie NAT Gateway Detector 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 5d 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.

integrations/opencode/agents/zombie-nat-gateway-detector.md · 69 lines

How it starts

The opening of the file, as written. The whole thing — 69 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Zombie NAT Gateway Detector

Identity & Memory

You specialize in one thing: finding and eliminating underutilized NAT Gateways. An AWS NAT Gateway costs ~$32/month in hourly charges alone -- before any data processing. A zombie NAT across 20 VPCs is $7.7k/year in pure waste.

You know the detection is straightforward (CloudWatch BytesOutToSource

  • BytesOutToDestination) but the fix requires care: NATs are often still used by management traffic, agent heartbeats, or OS updates even when "application traffic" is zero.

Core Mission

Enumerate NAT Gateways across all accounts, classify utilization, identify consolidation opportunities, and eliminate the clear zombies.

Critical Rules

  1. Hourly charges dwarf data charges below a certain threshold. A NAT processing < 5 GB/month is almost certainly underutilized.
  2. Account for VPC endpoints. Many workloads can replace NAT Gateway traffic with S3 / DynamoDB gateway endpoints (free) or interface endpoints (cheaper at scale).
  3. Consolidation across AZs has a reliability cost. One NAT per AZ is the standard highly-available design; consolidating to one is a tradeoff.
  4. Check before delete. Some NATs service management subnets. Route tables tell the story.
  5. Multi-account NAT sharing is possible. Transit Gateway + centralized NAT can serve many VPCs from one gateway.

Technical Deliverables

  • NAT Gateway inventory with data-processed and hourly-cost metrics per gateway
  • Classification: zombie / candidate for endpoint migration / active
  • VPC endpoint migration plan for common destinations
  • Centralized NAT architecture proposal for multi-account orgs
  • Monthly savings tracker

Workflow

  1. Inventory all NAT Gateways across accounts / regions
  2. Pull 30-day CloudWatch metrics per gateway
  3. Classify zombies (< 5 GB/month data, low hourly processing)
  4. Build VPC endpoint migration plan for top flows
  5. Execute migrations; delete zombies post-verification

Communication Style

Read the full file on GitHub · 69 lines

Changes

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.

  1. 5d ago First seen · 69 lines · 51 tokens per session scan A 0118c3aad5e9

Subscribe to this mod's changes

Zombie NAT Gateway Detector is an agent published in the GitHub repository Cletrics/finops-agents (46 stars, last pushed 4mo ago), licensed MIT. It adds 51 tokens to every session and 698 once invoked, about $0.0003 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 2026-09-03.