age-file-encryption

age-file-encryption is a skill for Claude Code, Codex from besoeasy/open-skills. It costs 57 tokens per session (1,994 once invoked), scanned C, original, MIT.

A command-line tool for encrypting and decrypting files or data streams. Encryption scrambles data so only people with the right key or passphrase can read it.

In plain words
What is it for?
It helps secure backups, send files to one or more recipients, encrypt data in scripts, and use existing SSH public keys.
Why use it?
It protects files before you store or share them without the complexity of larger encryption tools.

Skill for Claude CodeCodex

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

Good fit It helps secure backups, send files to one or more recipients, encrypt data in scripts, and use existing SSH public keys.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/besoeasy/open-skills/age-file-encryption
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 besoeasy/open-skills --skill age-file-encryption
Clone the repo
git clone --depth 1 https://github.com/besoeasy/open-skills

Made for: Claude Code, Codex.

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 age-file-encryption

README.md
[![agentmods](https://agentmods.dev/badge/skills/besoeasy/open-skills/age-file-encryption/github.svg)](https://agentmods.dev/skills/besoeasy/open-skills/age-file-encryption)
Your own site
<a href="https://agentmods.dev/skills/besoeasy/open-skills/age-file-encryption"><img src="https://agentmods.dev/badge/skills/besoeasy/open-skills/age-file-encryption/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 age-file-encryption

Your own site · 80×15
<a href="https://agentmods.dev/skills/besoeasy/open-skills/age-file-encryption"><img src="https://agentmods.dev/badge/skills/besoeasy/open-skills/age-file-encryption.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,994 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 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 $0.00057 $0.01994
Opus 5 $0.00028 $0.00997
Sonnet 5 $0.00011 $0.00399
Haiku 4.5 $0.00006 $0.00199

Measured 11d ago against content hash cd0d4f5b6934, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade C, and why

age-file-encryption scanned grade C 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 11d 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.

Reaches for credential fileshighPrivilege escalation

SSH keys, cloud credentials, git-credentials, .npmrc, /etc/shadow: reading these is how a config file becomes a credential leak.

age -R ~/.ssh/id_ed25519.pub secret.txt > secret.txt.age

Makes network callslowCapability

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

curl https://github.com/username.keys | age -R - secret.txt > secret.txt.age
skills/age-file-encryption/SKILL.md · 249 lines

How it starts

The opening of the file, as written. The whole thing — 249 lines — stays where its author put it; the contents beside it link to each section on GitHub.

age File Encryption

age is a minimal, modern encryption tool. It replaces GPG for most file encryption needs with a much simpler design: small explicit keys, no config files, and clean composability with UNIX pipes.

When to Use This Skill

  • Encrypting files or directories before storing or sharing them
  • Securely sending files to specific recipients by public key
  • Encrypting secrets with a passphrase for backup or storage
  • Encrypting to existing SSH public keys (ed25519 or RSA)
  • Encrypting to multiple recipients at once
  • Encrypting to a GitHub user's SSH keys
  • Automating encryption/decryption in scripts

Installation

# macOS / Linux (Homebrew)
brew install age

# Debian / Ubuntu 22.04+
apt install age

# Arch Linux
pacman -S age

# Alpine Linux
apk add age

# Fedora
dnf install age

# Windows
winget install --id FiloSottile.age

# From source (requires Go)
go install filippo.io/age/cmd/...@latest

Pre-built binaries:

https://dl.filippo.io/age/latest?for=linux/amd64
https://dl.filippo.io/age/latest?for=darwin/arm64
https://dl.filippo.io/age/latest?for=windows/amd64

Core Concepts

Term Meaning
recipient Public key — who can decrypt the file
identity Private key file — used to decrypt
age public key Starts with age1...
age private key Starts with AGE-SECRET-KEY-1..., stored in a key file

Key Generation

# Generate a key pair and save to key.txt
age-keygen -o key.txt
# Output: Public key: age1ql3z7hjy54pw3hyww5ayyfg7zqgvc7w3j2elw8zmrj2kg5sfn9aqmcac8p

# Print only the public key from an existing key file
age-keygen -y key.txt

Encrypting Files

With a recipient's public key

# Encrypt a file
age -r age1ql3z7hjy54pw3hyww5ayyfg7zqgvc7w3j2elw8zmrj2kg5sfn9aqmcac8p -o secret.txt.age secret.txt

# Using a pipe
cat secret.txt | age -r age1ql3z7hjy54... > secret.txt.age

With a passphrase

# age will prompt for a passphrase (or autogenerate a secure one)
age -p secret.txt > secret.txt.age

Read the full file on GitHub · 249 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. 11d ago First seen · 249 lines · 57 tokens per session scan C cd0d4f5b6934

Subscribe to this mod's changes

age-file-encryption is a skill published in the GitHub repository besoeasy/open-skills (132 stars, last pushed 6d ago), licensed MIT. It adds 57 tokens to every session and 1,994 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it C with 2 findings (reaches for credential files, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories

skill-creator

Create, install, or update skills in the workspace. Use when (1) installing a skill from a URL or remote source, (2) creating a new skill from scratch, (3) updating or restructuring existing skills. Always use this skill for any skill installation or creation task.

zhayujie/CowAgent · 61 tokens

peekaboo

Capture and automate macOS UI with the Peekaboo CLI.

the-open-agent/openagent · 17 tokens

powerpoint

Create designed, editable PowerPoint .pptx presentations with PptxGenJS. Use when the user asks to create, generate, update, or inspect a deck, slide deck, presentation, or .pptx file.

the-open-agent/openagent · 48 tokens

ax-agent-rlm

This skill helps an LLM generate correct AxAgent RLM/runtime code using @ax-llm/ax. Use when the user asks about RLM code execution, AxJSRuntime, contextFields, contextPolicy, liveRuntimeState, promptLevel, stage prompt controls, executorModelPolicy, maxRuntimeChars, agent.test(...), llmQuery(...), recursionOptions…

ax-llm/ax · 88 tokens

new-app

Scaffold a new Atomic Agents project from scratch — create the directory, pyproject.toml, env file, first agent, and a runnable entry point. Use when the user asks to start a new atomic-agents project from scratch, says "scaffold" / "new project" / "start from zero", or runs /atomic-agents:new-app.

Eigenwise/atomic-agents · 76 tokens

ax-go-flow

Use when writing Go code with github.com/ax-llm/ax/packages/go for flows, nodes, program graphs, nested programs, dynamic options, caching, and optimizer components.

ax-llm/ax · 43 tokens