explain-gpg

A plain-language guide to GPG, free software used for encryption, digital signatures, and cryptographic-key management.

In plain words
What is it for?
Use it to learn or explain GPG, create and manage keys, encrypt data, sign email, verify signatures, and connect GPG to command-line workflows.
Why use it?
It explains how GPG protects confidential information and verifies who created or approved a file or email. It also covers how keys, signatures, email formats, trust, and public key servers fit together.

Command

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 commands/nylas/cli/explain-gpg
Clone the repo
git clone --depth 1 https://github.com/nylas/cli
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 9,982 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 $0.00000 $0.09982
Opus 5 $0.00000 $0.04991
Sonnet 5 $0.00000 $0.01996
Haiku 4.5 $0.00000 $0.00998

Measured yesterday against content hash 2ee6939b2721, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

explain-gpg 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 yesterday.

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.

docs/commands/explain-gpg.md · 971 lines

How it starts

The opening of the file, as written. The whole thing — 971 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Understanding GPG: A Complete Guide

A comprehensive guide to GPG (GNU Privacy Guard) cryptography, email signing, and verification.


Table of Contents

  1. What is GPG?
  2. Asymmetric Cryptography
  3. GPG Key Anatomy
  4. Digital Signatures
  5. Email Signing (PGP/MIME)
  6. Signature Verification
  7. Trust Model
  8. Key Servers
  9. CLI Integration
  10. Security Considerations

What is GPG?

GPG (GNU Privacy Guard) is a free implementation of the OpenPGP standard (RFC 4880). It provides:

  • Digital Signatures - Prove authorship and integrity
  • Encryption - Protect confidential data
  • Key Management - Create, store, and share cryptographic keys
┌─────────────────────────────────────────────────────────────────┐
│                         GPG ECOSYSTEM                           │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│   ┌──────────────┐    ┌──────────────┐    ┌──────────────┐     │
│   │   OpenPGP    │    │     GPG      │    │  Key Servers │     │
│   │   Standard   │───▶│   Software   │◀──▶│   (Public)   │     │
│   │  (RFC 4880)  │    │              │    │              │     │
│   └──────────────┘    └──────────────┘    └──────────────┘     │
│                              │                                  │
│                              ▼                                  │
│                    ┌──────────────────┐                        │
│                    │   Your Keyring   │                        │
│                    │  ┌────────────┐  │                        │
│                    │  │Private Keys│  │                        │
│                    │  │Public Keys │  │                        │
│                    │  └────────────┘  │                        │
│                    └──────────────────┘                        │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Read the full file on GitHub · 971 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. yesterday First seen · 971 lines · 0 tokens per session scan A 2ee6939b2721

Subscribe to this mod's changes

explain-gpg is a command published in the GitHub repository nylas/cli (68 stars, last pushed 13d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 9,982 tokens. 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 2026-08-30.