How it works

  you press Enter
       │
       ▼
 ┌─────────────────────────────────────────┐
 │  UserPromptSubmit hook fires            │
 │  .env  ──────────────►  .env.enc        │
 │        AES-256-GCM                      │
 └─────────────────────────────────────────┘
       │
       ▼
  Claude runs — no plaintext secrets in context
       │
       ▼
 ┌─────────────────────────────────────────┐
 │  Stop hook fires                        │
 │  .env.enc  ──────────────►  .env        │
 │            decrypted                    │
 └─────────────────────────────────────────┘

Both operations are atomic — originals are only deleted after every output file is safely written.

Install

npm install @atillaersezke/envguard

Hooks are registered automatically on install. Nothing else to configure.

Hooks installed

# .claude/settings.local.json

hooks:
  UserPromptSubmit:
    - command: node node_modules/@atillaersezke/envguard/encrypt.mjs
  Stop:
    - command: node node_modules/@atillaersezke/envguard/decrypt.mjs

Encryption

algorithm : AES-256-GCM
key       : generated once  →  ~/.guard/crypto.key  (chmod 0600)
wire format:
  - iv        (12 bytes)
  - auth tag  (16 bytes)
  - ciphertext

File targeting

matches:
  pattern : "**/.env*"
  excludes:
    - "**/.env.example"   # never touched
    - "**/*.enc"          # already encrypted

skipped directories:
  - node_modules, .git
  - dist, build, .next, out
  - .venv, venv, __pycache__
  - coverage, logs, tmp, temp
  - vendor, public, static, .cache
  - target, bin, obj, frontend, .turbo

Requirements

• Node.js ≥ 18
• Claude Code
• PowerShell