respawn Brings Versioned Snapshots and Rollback to AI Agent Workflows

Summary

respawn is a beta command-line tool for versioning a directory tree as a content-addressed snapshot graph, with a stated focus on protecting worktrees before autonomous processes modify them. It stores file content in FastCDC-defined chunks addressed by BLAKE3, verifies objects during reads, reconstruction, and synchronization, and can detect drift against the current snapshot. Reverting swaps the HEAD pointer and rewrites files atomically one at a time; a crash can leave some files updated and others unchanged, but not a partially written file. The guard command snapshots a worktree, runs a command, reports its changes, propagates the command's exit status, and can restore the pre-command state on failure or always. Mutations use an operating-system file lock to enforce a single writer, while the audit log is hash-chained and can be checkpointed with Ed25519-signed anchors stored outside the repository state. Machines can replicate raw objects over a LAN, either with legacy plaintext or optional Noise-encrypted and authenticated PSK transport; plaintext protects integrity through hashes but not confidentiality. The design also validates manifest paths, blocks absolute paths, parent-directory traversal, and symlinked ancestors, and masks file modes to prevent setuid propagation. Its limits are explicit: it captures filesystem state rather than processes, memory, application state, or full permissions; ordinary snapshots are per-file quiesced captures rather than tree-atomic, and fast drift checks trust matching size and modification time unless --full is used. APFS point-in-time snapshots are supported on older compatible macOS configurations, but macOS 26 refuses mounting snapshots of the boot Data volume. There is no automatic watch-triggered snapshot mode. The project is distributed as a universal macOS beta binary through Homebrew, is licensed under FSL-1.1-ALv2, and has not undergone an external security audit.