atmos-validation

atmos-validation is a skill for Claude Code from cloudposse/atmos. It costs 31 tokens per session (1,980 once invoked), scanned A, original, Apache-2.0.

A validation framework for checking Atmos projects and related files against configuration rules, schemas, policies, and formatting standards. It can also validate only files affected by a change.

In plain words
What is it for?
Use it to validate Atmos configuration, stack manifests, components, JSON Schema files, EditorConfig rules, and GitHub Actions workflows.
Why use it?
It catches invalid configuration and policy violations before they reach deployment or CI, and can focus checks on changed project inputs.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the atmos plugin — 51 skills shipped together

About the project

Atmos is an infrastructure runtime that coordinates tools such as Terraform, OpenTofu, Kubernetes, Helm, Packer, Ansible, and containers through consistent commands and configuration. It is for teams running cloud infrastructure on laptops, in CI, or through AI agents across environments and regions. Its catalogue entries provide skills, agents, commands, and other add-ons for Atmos workflows.

cloudposse/atmos · 1,372 stars · on GitHub · atmos.tools

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.

agentmods
npx agentmods add skills/cloudposse/atmos/atmos-validation
Any agent
npx skills add cloudposse/atmos --skill atmos-validation
Clone the repo
git clone --depth 1 https://github.com/cloudposse/atmos

Made for: Claude Code.

Or install atmos, the plugin that ships this one along with the rest of its 51 skills.

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 atmos-validation

README.md
[![agentmods](https://agentmods.dev/badge/skills/cloudposse/atmos/atmos-validation.svg)](https://agentmods.dev/skills/cloudposse/atmos/atmos-validation)
Your own site
<a href="https://agentmods.dev/skills/cloudposse/atmos/atmos-validation"><img src="https://agentmods.dev/badge/skills/cloudposse/atmos/atmos-validation.svg" alt="Measured on agentmods" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,980 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00031 $0.01980
Opus 5 $0.00015 $0.00990
Sonnet 5 $0.00006 $0.00396
Haiku 4.5 $0.00003 $0.00198

Measured 2d ago against content hash fce873582f16, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

atmos-validation 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 2d 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.

agent-skills/skills/atmos-validation/SKILL.md · 253 lines

How it starts

The opening of the file, as written. The whole thing — 253 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Atmos Validation Framework

Use this skill for every Atmos validation command and validation policy configuration: aggregate project validation, configuration and stack schemas, JSON Schema, OPA/Rego, EditorConfig, GitHub Actions workflows, affected-file selection, and native CI reporting.

For detailed JSON Schema examples, read references/json-schema.md. For OPA/Rego policy patterns, read references/opa-policies.md. For project-wide, affected, and CI validation behavior, read references/project-validation.md.

Start with the Validation Target

Need Command
Run every project validator atmos validate
Validate only changed project inputs atmos validate --affected
Validate atmos.yaml atmos validate config or atmos config validate
Validate stack manifests atmos validate stacks or atmos stack validate
Validate .editorconfig rules atmos validate editorconfig
Lint GitHub Actions workflows with actionlint atmos ci validate or atmos validate ci
Validate arbitrary files against JSON Schema atmos validate schema <key>
Validate resolved component input atmos validate component <component> -s <stack>

Start with the narrowest command that matches the change. Use the aggregate command for a repository gate because it reports every applicable validator instead of stopping at the first one.

Validation Commands

atmos validate component vpc -s plat-ue2-prod
atmos validate stacks
atmos validate schema github-actions
atmos validate --affected --format rich

atmos validate component validates a component in a stack using settings.validation or explicit --schema-path / --schema-type flags.

atmos validate stacks validates stack YAML syntax, imports, duplicate component definitions, and manifest schema compliance.

atmos validate schema <key> validates arbitrary files matched by a schemas.<key>.matches glob against a JSON Schema.

Read the full file on GitHub · 253 lines

Files

What ships with it

3 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.

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. 2d ago First seen · 253 lines · 31 tokens per session scan A fce873582f16

Subscribe to this mod's changes

atmos-validation is a skill published in the GitHub repository cloudposse/atmos (1,372 stars, last pushed today), licensed Apache-2.0. It adds 31 tokens to every session and 1,980 once invoked, about $0.0002 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.

Related

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