Add CLAUDE.md for Claude Code guidance

Provides build/test commands, architecture overview, and development
workflow notes including green-red-green testing cycle.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Build and Test Commands
+
+```bash
+# Run tests
+uv run pytest
+
+# Run a single test
+uv run pytest test_mcquack.py::TestCreate::test_create_with_arguments
+
+# Run tests matching a pattern
+uv run pytest -k "test_edit"
+
+# Type checking (uses ty via pre-commit)
+uvx ty check
+
+# Run pre-commit hooks manually
+uv run pre-commit run --all-files
+
+# Run the CLI directly (no install needed)
+./mcquack.py list
+```
+
+## Architecture
+
+mcquack is a single-file Python CLI (`mcquack.py`) that manages macOS LaunchAgents for executable scripts. It uses a uv script shebang (`#!/usr/bin/env -S uv run --script`) so it can be run directly without installation.
+
+**Key components in mcquack.py:**
+- `app` - Typer CLI application with commands: `list`, `create`, `launch`, `show`, `edit`, `unload`, `delete`
+- `LAUNCH_AGENTS_DIR` / `LOGS_DIR` - Paths to `~/Library/LaunchAgents` and `~/Library/Logs`
+- `get_plist_path()` / `get_label()` - Generate plist paths and launchd labels from script paths
+- `create_plist_dict()` - Builds the plist dictionary structure
+
+**Plist naming convention:** `mcquack.eblume.<scriptname>.plist`
+
+**Test architecture:**
+- `conftest.py` - Fixtures that mock `LAUNCH_AGENTS_DIR`, `LOGS_DIR`, and `subprocess.run` to avoid real launchctl calls
+- Tests use `typer.testing.CliRunner` to invoke CLI commands
+
+## Important Patterns
+
+- Commands that accept script arguments (`create`, `edit`) require `--` separator to distinguish mcquack flags from script args
+- All launchctl interactions go through `subprocess.run` - tests mock this to avoid system modifications
+- The `mock_dirs` fixture monkeypatches module-level path constants for test isolation
+
+## Development Workflow
+
+- Use a green-red-green testing cycle: verify tests pass, write a failing test for new behavior, then implement until green
+- Run type checking frequently with `uvx ty check`