ADR-004: Chezmoi + Custom CLI Wrapper Architecture

Status: Accepted; command layout superseded by ADR-020 Date: 2026-02-09 Authors: @sebastienrousseau

Status note (0.2.539): Chezmoi as the engine with dot as the wrapper still holds. The command modules, the scripts/dot/commands/ layout, the delegation pattern and "Adding a New Command" below are the original design. Today each domain is a plugin: it is declared in plugins/<domain>/dot-plugin.toml, runs from plugins/<domain>/dot-<domain> (or its libexec/), and bin/dot dispatches through the command table built from the plugins' route fragments. Commands are spelled dot <domain> [object] <verb> (ADR-020). Only diagnostics.sh, manual.sh and meta.sh remain in scripts/dot/commands/.

Context

Managing dotfiles requires:

• Tracking file changes and applying them consistently
• Handling platform-specific configurations
• Supporting encrypted secrets
• Providing a good developer experience

Options considered:

1. Bare git repository: Simple but poor UX, no templating
2. GNU Stow: Symlink-based, limited features
3. Chezmoi only: Powerful but complex CLI
4. Custom from scratch: High maintenance burden
5. Chezmoi + wrapper: Best of both worlds

Decision

Use Chezmoi as the core engine with a custom dot CLI wrapper that:

Architecture

┌─────────────────────────────────────────────┐
│                 dot CLI                      │
│  (User-friendly interface, custom commands)  │
├─────────────────────────────────────────────┤
│              Command Modules                 │
│  core │ diagnostics │ tools │ appearance    │
│  secrets │ security │ meta                   │
├─────────────────────────────────────────────┤
│              Shared Library                  │
│  utils.sh (resolve_source_dir, run_script)  │
├─────────────────────────────────────────────┤
│                 Chezmoi                      │
│  (Template engine, state management, apply)  │
└─────────────────────────────────────────────┘

Core Principles

1. Chezmoi handles complexity:

• Template rendering with Go text/template
• Encrypted secrets with age
• State tracking (what's applied vs source)
• Cross-platform path handling

2. dot CLI handles UX:

• Memorable command names (dot sync vs chezmoi apply)
• Domain-specific commands (dot doctor, dot theme)
• Integration with external tools (Nix, Docker, Neovim)
• Consistent help and error messages

3. Modular command structure:

scripts/dot/
├── lib/
│   └── utils.sh          # Shared functions
└── commands/
    ├── core.sh           # apply, sync, update, add, diff
    ├── diagnostics.sh    # doctor, heal, health, benchmark
    ├── tools.sh          # tools, new, packages
    ├── appearance.sh     # theme, wallpaper, fonts
    ├── secrets.sh        # secrets-init, secrets
    ├── security.sh       # firewall, backup, encrypt-check
    └── meta.sh           # upgrade, docs, learn

4. Delegation pattern:

# Main dispatcher in dot CLI
dispatch() {
  local module="$1" cmd="$2"
  shift 2
  exec bash "$src_dir/scripts/dot/commands/$module.sh" "$cmd" "$@"
}

Chezmoi Integration Points

Extension Points

Custom commands can:

1. Wrap chezmoi commands with better defaults
2. Add entirely new functionality (benchmarks, themes)
3. Integrate with system tools (nix, docker, brew)
4. Provide interactive experiences (tour, learn)

Consequences

Positive

• Leverage Chezmoi's battle-tested engine
• User-friendly interface for common tasks
• Easy to add domain-specific commands
• Modular structure enables testing and maintenance
• Single entry point (dot) for all operations

Negative

• Two layers to understand (chezmoi + dot)
• Version coupling between chezmoi and scripts
• Some chezmoi features not exposed via dot

Neutral

• Advanced users can still use chezmoi directly
• Documentation needed for both layers
• Upgrade path when chezmoi adds new features

Implementation Notes

Adding a New Command

The steps below are the original ones. For a command today, declare it in the domain's plugins/<domain>/dot-plugin.toml and follow ADR-020.

1. Identify the appropriate module (or create new one)
2. Add function cmd_<name>() to module
3. Add case to module's dispatch
4. Add case to main dot CLI dispatcher
5. Update help text
6. Add tests if complex

Module Template

#!/usr/bin/env bash
# Dotfiles CLI - <Category> Commands

set -e

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/../lib/utils.sh"

cmd_example() {
  # Implementation
}

case "${1:-}" in
  example) shift; cmd_example "$@" ;;
  *) echo "Unknown command: ${1:-}" >&2; exit 1 ;;
esac

References

• Chezmoi Documentation
• Command Pattern
• Unix Philosophy