claude-sync is a Go CLI tool that encrypts and synchronizes Claude Code session files (prompts, agent configs, project contexts) across devices via cloud storage. It uses a pluggable storage backend (S3, R2, GCS, WebDAV), end-to-end encryption with age (X25519 + Argon2id key derivation), gzip compression, and state-based incremental sync. The tool provides commands for push, pull, status, diff, conflict resolution, history rebuild, and auto-sync hooks. It is distributed as an npm package that downloads a platform-specific Go binary. The architecture follows a clean internal separation: storage adapters, crypto, config, paths, syncer, and CLI commands. The code is well-tested (unit + integration) and includes CI/CD pipelines, though there is a Go version mismatch (go.mod requires 1.24, CI uses 1.21) and some security notes (plaintext credentials, no checksum verification in postinstall). The project is actively developed with a mature feature set and offers reusable patterns like the storage interface, cross-device path mapping, and three-way MCP merge.