Clarc is a native macOS desktop client for the Claude Code CLI, built with SwiftUI and Swift 6. It provides a project-centric GUI that wraps the terminal-based Claude Code agent, making it accessible to users who prefer a graphical interface. The application manages multiple projects (local folders or GitHub repositories), each with per-project session history, file browser, Git status, embedded terminal, memo pad, and a full-featured chat interface. It integrates deeply with the Claude Code CLI by spawning it as a subprocess, reading/writing its JSONL session files, and rendering tool calls (Bash, Edit, Write, MultiEdit, AskUserQuestion) with rich UI components like diffs and collapsible transient groups. Architecturally, Clarc is a standard macOS app with a monolithic AppState at the center, supported by several service modules (PersistenceService, GitHubService, ClaudeService, RateLimitService, MarketplaceService) and a reusable Swift Package (ClarcChatKit) for chat UI components. The codebase demonstrates solid craftsmanship: clean localization in 6 languages, Sparkle-based auto-updating, well-structured test coverage for core parsing logic, and thoughtful patterns for session normalization and sidecar metadata. The chat UI package is particularly well-isolated and could be reused in other SwiftUI chat applications. The application does not contain any data science or research components; it is purely a client application. However, it does handle complex data flows around session persistence and CLI integration, showing careful engineering for edge cases like in-flight streaming, legacy migration, and tool result pairing.