12-factor-apps

12-factor-apps is a skill for Claude Code, Codex from ivklgn/ai-kit. It costs 43 tokens per session (4,781 once invoked), scanned A, a copy of 12-factor-apps, MIT.

A codebase audit against the Twelve-Factor App methodology, a checklist for building software-as-a-service applications that can be deployed and scaled across environments.

In plain words
What is it for?
Use it to review a SaaS or cloud application, assess its architecture, and identify departures from Twelve-Factor practices.
Why use it?
It helps reveal architecture choices that make deployment, scaling, or maintenance harder. The analysis checks the codebase against each of the methodology's factors.

Skill for Claude CodeCodex

Part of the ai-kit plugin — 12 skills, 14 commands, 30 agents, 1 MCP server shipped together

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/ivklgn/ai-kit/12-factor-apps
Any agent
npx skills add ivklgn/ai-kit --skill 12-factor-apps
Clone the repo
git clone --depth 1 https://github.com/ivklgn/ai-kit

Made for: Claude Code, Codex.

Or install ai-kit, the plugin that ships this one along with the rest of its 12 skills, 14 commands, 30 agents, 1 MCP server.

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 12-factor-apps

README.md
[![agentmods](https://agentmods.dev/badge/skills/ivklgn/ai-kit/12-factor-apps.svg)](https://agentmods.dev/skills/ivklgn/ai-kit/12-factor-apps)
Your own site
<a href="https://agentmods.dev/skills/ivklgn/ai-kit/12-factor-apps"><img src="https://agentmods.dev/badge/skills/ivklgn/ai-kit/12-factor-apps.svg" alt="Measured on agentmods" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,781 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 2 findings. Scan, not verified.
Origin 94% copy Near-identical to another mod 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 $0.00043 $0.04781
Opus 5 $0.00022 $0.02390
Sonnet 5 $0.00009 $0.00956
Haiku 4.5 $0.00004 $0.00478

Measured 4d ago against content hash 0b619a198cb8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

12-factor-apps scanned grade A with 2 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 4d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

grep -r "subprocess.*curl\|subprocess.*wget\|os.system.*ffmpeg\|shutil.which" --include="*.py"

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

grep -r "subprocess.*curl\|subprocess.*wget\|os.system.*ffmpeg\|shutil.which" --include="*.py"
Origin

This is a copy

94% identical to 12-factor-apps — 6 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/ai-kit/skills/12-factor-apps/SKILL.md · 547 lines

How it starts

The opening of the file, as written. The whole thing — 547 lines — stays where its author put it; the contents beside it link to each section on GitHub.

12-Factor App Compliance Analysis

Source & attribution. Ported from the 12-factor-apps skill by anderskev, published on clawhub.ai (https://clawhub.ai/anderskev/12-factor-apps), released under MIT-0. Methodology: The Twelve-Factor App by Adam Wiggins. See ATTRIBUTION.md.

Overview

The 12-Factor App methodology is a set of best practices for building Software-as-a-Service applications that are:

  • Portable across execution environments
  • Scalable without architectural changes
  • Suitable for continuous deployment
  • Maintainable with minimal friction

Input Parameters

Parameter Description Required
codebase_path Root path of the codebase to analyze Required

Analysis Framework

Factor I: Codebase

Principle: One codebase tracked in revision control, many deploys.

Search Patterns:

# Check for version control
ls -la .git 2>/dev/null || ls -la .hg 2>/dev/null

# Check for multiple apps sharing codebase
find . -name "package.json" -o -name "pyproject.toml" -o -name "setup.py" | head -20

# Check for environment-specific code branches
grep -r "if.*production\|if.*development\|if.*staging" --include="*.py" --include="*.js" --include="*.ts"

File Patterns: .git/, package.json, pyproject.toml, deployment configs

Compliance Criteria:

Level Criteria
Strong Single Git repo, same codebase for all environments, no env-specific code branches
Partial Single repo but some environment-specific code paths
Weak Multiple repos for same app or significant code duplication across environments

Anti-patterns:

  • Multiple Git repositories for the same application
  • Environment-specific code branches (if production: ...)
  • Different source files for dev vs prod
  • Shared code not extracted to libraries

Factor II: Dependencies

Principle: Explicitly declare and isolate dependencies.

Read the full file on GitHub · 547 lines

Files

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.

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. 4d ago First seen · 547 lines · 43 tokens per session scan A 0b619a198cb8

Subscribe to this mod's changes

12-factor-apps is a skill published in the GitHub repository ivklgn/ai-kit (12 stars, last pushed yesterday), licensed MIT. It adds 43 tokens to every session and 4,781 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 2 findings (makes network calls, runs shell commands). It is 94% identical to 12-factor-apps, differing in 6 lines, and is treated as a copy.

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