dotfiles/home/dot_claude/CLAUDE.md.tmpl

**Note**: Project-specific CLAUDE.md files take precedence for project-specific patterns.

{{- if and (eq .chezmoi.os "windows") (not .wsl) }}

## Shell Environment (Windows)

- **You are in Bash on Windows** (Git Bash / MSYS2)
- ❌ Do NOT use PowerShell commands (`Get-ChildItem`, `Select-Object`, `Move-Item`)
- ❌ Do NOT use CMD commands (`dir`, `copy`, `del`)
- ✅ Use standard Bash/Unix commands (`ls`, `cp`, `mv`, `rm`, `grep`)
- Prefer relative paths for simplicity
{{- else if .wsl }}

## Shell Environment (WSL)

- **You are in WSL (Windows Subsystem for Linux)**
- ✅ Use standard Linux/Bash commands (`ls`, `cp`, `mv`, `rm`, `grep`)
- ✅ Full access to Linux tooling and package managers
- ⚠️ Can access Windows filesystem via `/mnt/c/`, but prefer Linux paths
- ⚠️ Can call Windows executables (`.exe`), but prefer native Linux tools
- Prefer relative paths for simplicity
{{- else if eq .chezmoi.os "linux" }}

## Shell Environment (Linux)

- **You are in a standard Linux environment**
- ✅ Use standard Bash/Unix commands (`ls`, `cp`, `mv`, `rm`, `grep`)
- ✅ Full access to Linux tooling and package managers
- Prefer relative paths for simplicity
{{- end }}

## Build & Package Management

### General Principles

- **NEVER invoke `cargo clean`** - rarely necessary and wastes time
- **Avoid running full builds unless necessary** - prefer type checking and linting
- Run cargo build or any build commands with lots of output in 'quiet' mode, unless you require access to stacktrace/warnings/etc
- Alternatively, avoid running the command and stop the prompt there if you simply want the user to test and report back

### Dependency Management

- **Always use package manager commands** over manually editing manifest files:
  - Rust: `cargo add`, `cargo remove`
  - Node.js: `pnpm add`, `pnpm remove` (or npm/yarn as appropriate)
- This ensures lockfiles are updated correctly and consistently
- **Get the latest compatible version** unless there's a specific reason not to
  - You can specify versions, but prefer letting the tool grab the latest
  - Your knowledge cutoff means you often don't know the latest versions

### Check Commands

- Look for project-specific commands first (`just check`, `just test`, etc.)
- Always prefer project-specific check commands over raw `cargo` or `npm` commands

## Testing

### Test Organization

- **Integration/feature tests**: Place in `tests/` directory
- **Unit tests**: Place alongside the code they test directly (in same file or adjacent `tests.rs`)
- Always check project conventions before adding tests

### Running Tests

- Use project-specific test commands (e.g., `just test`) over raw `cargo test`
- Prefer `cargo nextest run` for executing tests (unless `just test` is available, regardless of what it invokes)
- Run tests after making changes to verify functionality

### Assertion Style (Rust)

When a project uses `assert2`:
- Use `assert2::assert!()` instead of `assert_eq!()`
- Use `assert2::let_assert!()` for pattern matching
- Use `assert2::check!()` for non-fatal assertions

## Code Style

### Rust

- Prefer direct imports when heavily used: `use glam::U16Vec2;` then `U16Vec2::new()`
- Prefer iterators and combinators over for loops when idiomatic
- Prefer slices (`&[T]`) for read-only parameters over `&Vec<T>`
- Use `#[inline]` for hot-path functions

### TypeScript

- **Prefer absolute imports** (`@/...`) over relative imports when available
  - Not always necessary or possible - use judgment
  - Clearer and easier to refactor when the pattern exists in the project
- Prefer functional programming patterns (map, filter, reduce) over for loops when idiomatic

### General Pattern

- **Write idiomatic code for the language**:
  - Rust: iterators, combinators, Option/Result patterns
  - TypeScript: functional patterns, modern ES6+ features
  - Check existing code patterns before implementing

## Comments & Documentation

- Write comments that explain **WHY**, not **WHAT**
- **Never reference old implementations, migrations, or refactoring history**
- **Never add banner comments** (`===`, `-----`, etc.)
- Update project CLAUDE.md when making architectural decisions
- Examples of bad comments to avoid:
  - "Refactored from previous version that used X approach." (never mention past implementations)
  - "This function was changed to improve performance." (utterly useless, belongs in a commit message potentially, but not code!)
  - "Logging removed for cleaner output." (also useless, belongs in commit message if anything)

## Git Commits

### Safety & Best Practices

- **Do NOT add co-authoring or attribution to Claude Code/AI**
- **Be very careful with commit history**:
  - Avoid rewriting history unless explicitly prompted by user
  - **Check if commits actually went through** when hooks fail
  - **Never accidentally amend previous commits** when user meant to create new one
  - If pre-commit or hooks fail, verify the commit status before retrying
- Write concise commit messages focusing on "why" rather than "what"
- If writing the first commit, assume conventional commit style unless user specifies otherwise.
- For subsequent commits, follow the project's existing commit style.
- Scale the length and detail of the commit message to the impact of the changes.
  - A simple rename of a function or type may interact with many files, but it does not deserve a length message.
  - A complex feature addition or refactor deserves a more detailed message explaining the reasoning. Still, keep things concise.
  - Never include details like "All tests pass, 92% coverage. A few warnings."

## AI Development Workflow

### Standard Workflow

`modify code → check → test → hand off to user`

1. Make code changes
2. Run project-specific check commands
3. Run tests if applicable
4. **Hand off to user** - do NOT run dev servers or long-running processes
5. Wait for user feedback

### Codebase Exploration

- **Avoid super complex bash/sed/awk commands** when exploring
- Use existing tools (Read, Glob, Grep) to manually explore instead
- Check for existing libraries, frameworks, and code patterns before creating new utilities/APIs

### Question Tool Usage

- **Use for complex tasks and design decisions**:
  - Architectural choices
  - Multiple implementation approaches
  - Feature design options
  - Clarifying & confirming important requirements, especially vague or conflicting ones
- **Do NOT use for trivial details**:
  - Variable naming
  - Minor formatting choices
- **Prefer multi-select when appropriate**, single-select when mutually exclusive
- User appreciates being consulted on larger, more abstract decisions

### When NOT to Build/Run

- ❌ After type checking passes - building is unnecessary
- ❌ Dev servers (`pnpm dev`, `cargo run`, etc.)
- ❌ Long-running processes or interactive tools
- ✅ Only build when user explicitly requests or verifying build config

## Tool Usage

### Prefer Specialized Tools Over Bash

- Read tool for reading files (not `cat`, `head`, `tail`)
- Edit tool for editing files (not `sed`, `awk`)
- Write tool for creating files (not `echo >`)
- Glob tool for finding files (not `find`, `ls`)
- Grep tool for searching (not `grep`, `rg`)
- Bash ONLY for actual system commands and terminal operations

## Security & Error Handling

- Watch for security vulnerabilities: command injection, XSS, SQL injection, OWASP Top 10
- If you write insecure code, **immediately fix it**
- Validate all external inputs
- Use appropriate error types for the language

## Quick Reference

### After Making Changes

```bash
# 1. Check (find project-specific command)
just check              # or equivalent

# 2. Run tests (if applicable)
just test               # or equivalent

# 3. STOP - hand off to user for testing
```

### What to Avoid

- Don't run dev servers, builds, or interactive processes yourself
- Don't use complex bash pipelines when simpler tools exist
- Don't manually edit manifests when package manager commands exist
- Don't assume commits went through when hooks fail

---

**Remember**: Check for project-specific CLAUDE.md files that override these global guidelines.