gw Configuration Management Skill

gw Configuration Management

Config lives at .gw/config.json (committable) and .gw/config.local.json (gitignored, personal overrides). All worktrees in a repo share the same config.

MANDATORY: Config-Change Rules

Non-negotiable in any gw-tools repo.

| Situation | Required action | | ------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ | | Adding or renaming a Config field in types.ts | Add a migration in config-migrations.ts, increment CURRENT_CONFIG_VERSION, update gw-config.schema.json, and update types.ts | | Removing a field from Config | Same as above — use a migration to delete it; never just remove from code | | Old field in existing configs must keep working | Write a migration that renames/transforms it. NEVER add backcompat shims in command code | | configVersion in a committed config | Never edit it manually; gw manages it automatically | | gw-config.schema.json diverges from Config | Fix immediately — the schema is additionalProperties: false and IDE errors surface in every committed config |

The canonical migration guide is in the project root CLAUDE.md under "Config Migration System". See also packages/gw-tool/src/lib/config-migrations.ts (current version: CURRENT_CONFIG_VERSION = 2).

Rules

| Rule | Description | | ------------------------------------------------- | --------------------------------------------------------- | | fundamentals | HIGH - Config file location, creation, and precedence | | options-reference | HIGH - Complete reference for all config options | | setup | HIGH - Initial setup flow, secrets, team onboarding | | auto-copy | HIGH - File patterns to copy, what to include/exclude | | team-config | MEDIUM - Sharing config, documentation, onboarding | | advanced | LOW - Multiple sources, secret management integration | | troubleshooting | HIGH - Common issues and solutions |

Complete Config Reference

{
  // Added automatically by gw init — enables IDE autocompletion/validation
  "$schema": "https://raw.githubusercontent.com/mthines/gw-tools/main/packages/gw-tool/schemas/gw-config.schema.json",

  // Managed automatically — do not edit manually
  "configVersion": 2,

  // Branch whose worktree is the source for auto-copy and sync (default: "main")
  // This worktree is protected from auto-clean.
  "defaultBranch": "main",

  // Files/dirs copied from defaultBranch worktree when gw checkout runs.
  // Paths are relative to repo root. Directories end with /. Non-existent entries are skipped with a warning.
  "autoCopyFiles": [".env", ".env.local", "secrets/"],

  // Commands run before/after gw checkout. Supports variable substitution (see Hooks below).
  "hooks": {
    "checkout": {
      // Pre-hooks: run before worktree creation. Failure aborts the checkout.
      "pre": ["echo 'Creating: {worktree}'"],
      // Post-hooks: run after successful creation. Failure warns but does NOT roll back.
      "post": ["cd {worktreePath} && pnpm install"],
    },
  },

  // Days before worktrees are considered stale for gw clean / auto-clean (default: 7)
  "cleanThreshold": 7,

  // When true, silently prunes stale worktrees after gw checkout / gw list.
  // Never removes defaultBranch. Only removes worktrees with no uncommitted or unpushed changes. (default: false)
  "autoClean": false,

  // Default strategy for gw update: "merge" (preserves history) or "rebase" (linear). (default: "merge")
  // Override per-command with --merge or --rebase flags.
  "updateStrategy": "merge",
}

Local overrides — create .gw/config.local.json to override any field for your machine only. It is gitignored automatically and shallow-merged on top of config.json (local wins).

Hook Variables

Available for substitution in any hook command string:

| Variable | Value | | ---------------- | ----------------------------------------------------- | | {worktree} | Worktree name (e.g. feat/my-feature) | | {worktreePath} | Absolute path to the new worktree | | {gitRoot} | Absolute path to the bare git repository root | | {branch} | Branch name (same as worktree name for gw checkout) |

Example using variables:

{
  "hooks": {
    "checkout": {
      "post": ["cd {worktreePath} && pnpm install", "echo 'Ready at {worktreePath}'"],
    },
  },
}

Adding a Migration (required when changing `Config`)

When any field in packages/gw-tool/src/lib/types.ts's Config interface is added, renamed, or removed, follow this checklist — see root CLAUDE.md for the full authoritative process:

Increment CURRENT_CONFIG_VERSION in config-migrations.ts
Add a migration entry to the MIGRATIONS array that transforms old configs and sets config.configVersion = <new version>
Update types.ts to reflect the new shape
Update schemas/gw-config.schema.json — add/remove/rename properties, update "default" on configVersion to the new version
Remove any command-level backcompat code — migrations own backwards compatibility

Migration skeleton:

{
  version: 3, // next version number
  description: 'Rename oldField to newField',
  migrate: (config) => {
    if (config.oldField !== undefined) {
      config.newField = config.oldField;
      delete config.oldField;
    }
    config.configVersion = 3;
    return config;
  },
}

Quick Command Reference

| Task | Command | | ------------------------------ | ------------------------------------------------------------------------ | | Initialize config | gw init | | Init with options | gw init --auto-copy-files .env,secrets/ --post-checkout "pnpm install" | | Interactive setup | gw init --interactive | | Clone and initialize | gw init git@github.com:user/repo.git | | Show generated init command | gw show-init | | Sync files to current worktree | gw sync | | Sync to specific worktree | gw sync feat/branch | | Sync specific files | gw sync feat/branch .env .env.local |

Anti-Patterns

| Anti-pattern | Correct approach | | ------------------------------------------------------------ | ---------------------------------------------------------------------------------- | | Adding a Config field without a migration | Always add a migration; bump CURRENT_CONFIG_VERSION | | Handling an old field name in command code | Delete the handling; write a migration instead | | Editing configVersion in a config file by hand | Let gw manage it; never edit manually | | Updating types.ts without updating gw-config.schema.json | Both files must stay in sync — the schema is additionalProperties: false | | Listing node_modules/ or dist/ in autoCopyFiles | Only list secrets and env files that won't regenerate | | Committing .gw/config.local.json | It is gitignored by design; keep machine-specific overrides out of version control | | Adding absolute paths to autoCopyFiles | Paths must be relative to the repo root |

Key Principles

Set up secrets in defaultBranch first — source must exist before auto-copy works.
Commit config.json to version control — team members get it automatically.
Copy secrets, not dependencies — .env yes, node_modules/ no.
Migrations own backwards compat — never add shims in command code.
gw show-init documents your setup — generates a shareable init command from current config.

Related Skills

git-worktree-workflows - Using worktrees effectively (gw checkout, gw cd, gw clean, etc.)
autonomous-workflow - Autonomous development in isolated worktrees (lives in mthines/agent-skills)

Resources

Project-Type Guides - Configuration guides for Next.js, Node.js API, monorepo, React SPA
Next.js Setup Example
Monorepo Setup Example
Troubleshooting Guide

Agent Skills: gw Configuration Management

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