atmos-schemas

atmos-schemas is a skill for Claude Code, Codex from cloudposse/atmos. It costs 32 tokens per session (2,094 once invoked), scanned A, original, Apache-2.0.

A guide to validating Atmos YAML files with JSON Schema. JSON Schema is a machine-readable description of allowed fields and values; editors can use it for completion and error highlighting.

In plain words
What is it for?
Use it to validate stack manifests, atmos.yaml, and other YAML files against schemas, with IDE completion and hover descriptions.
Why use it?
It catches configuration mistakes early and helps the editor explain which Atmos options are valid for the installed version.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Part of the atmos plugin — 51 skills shipped together

Good fit Use it to validate stack manifests, atmos.yaml, and other YAML files against schemas, with IDE completion and hover descriptions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cloudposse/atmos/atmos-schemas
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.

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

Made for: Claude Code, Codex.

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-schemas

README.md
[![agentmods](https://agentmods.dev/badge/skills/cloudposse/atmos/atmos-schemas/github.svg)](https://agentmods.dev/skills/cloudposse/atmos/atmos-schemas)
Your own site
<a href="https://agentmods.dev/skills/cloudposse/atmos/atmos-schemas"><img src="https://agentmods.dev/badge/skills/cloudposse/atmos/atmos-schemas/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 atmos-schemas

Your own site · 80×15
<a href="https://agentmods.dev/skills/cloudposse/atmos/atmos-schemas"><img src="https://agentmods.dev/badge/skills/cloudposse/atmos/atmos-schemas.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,094 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00032 $0.02094
Opus 5 $0.00016 $0.01047
Sonnet 5 $0.00006 $0.00419
Haiku 4.5 $0.00003 $0.00209

Measured 5d ago against content hash d73ae384d147, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

atmos-schemas 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.

agent-skills/skills/atmos-schemas/SKILL.md · 232 lines

How it starts

The opening of the file, as written. The whole thing — 232 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Atmos JSON Schema System

Overview

Atmos uses JSON Schema (Draft 2020-12) to validate configuration files, provide IDE auto-completion, and catch configuration errors early. Two schemas cover the core file types:

  1. Stack manifest schema -- Validates stack YAML manifests (stacks/**). Published at https://atmos.tools/schemas/atmos/atmos-manifest/1.0/atmos-manifest.json and registered with SchemaStore as https://json.schemastore.org/atmos-manifest.json. Used by atmos validate stacks and by IDEs for auto-completion.

  2. CLI configuration schema -- Validates atmos.yaml itself (every configuration section the CLI reads). Published at https://atmos.tools/schemas/atmos/atmos-config/1.0/atmos-config.json. Used by atmos validate schema config and by IDEs for auto-completion. This schema is generated from the Atmos configuration code, so it always matches the options the installed release actually supports -- including YAML function alternatives (like logs: !include shared.yaml) and descriptions for hover text.

Users can also validate arbitrary YAML files against arbitrary schemas via schemas.<key> entries in atmos.yaml (see "Custom Schema Validation" below), and vendor.yaml manifests are validated against a built-in vendor schema.

Floating vs. Pinned Schema URLs

Both schemas are published in two forms:

  • Floating -- .../atmos-manifest/1.0/atmos-manifest.json and .../atmos-config/1.0/atmos-config.json always reflect the latest Atmos release.
  • Pinned -- .../atmos-manifest/<atmos-version>/atmos-manifest.json and .../atmos-config/<atmos-version>/atmos-config.json are immutable snapshots of the schema exactly as it shipped with that release. Pin when a team upgrades the Atmos binary on its own schedule and must not silently absorb schema changes. Pinned URLs only exist for versions released after pinning shipped; earlier releases only have the floating 1.0 path.

Validating atmos.yaml (CLI Configuration)

Read the full file on GitHub · 232 lines

Files

What ships with it

1 file 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. 5d ago First seen · 232 lines · 32 tokens per session scan A d73ae384d147

Subscribe to this mod's changes

atmos-schemas is a skill published in the GitHub repository cloudposse/atmos (1,372 stars, last pushed today), licensed Apache-2.0. It adds 32 tokens to every session and 2,094 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.

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