Checkpoint

Shadow git checkpoint system that snapshots and restores working directory state using an isolated git repository. The project's .git history is never touched.

Skill type: Rigid — follow exactly, no shortcuts.

Execution model: No modes, no subagent dispatch. The consuming orchestrator (build, quality-gate, debugging) follows these instructions directly when taking or restoring checkpoints.

Shadow Repository Setup

Initialize once per session, on first checkpoint request:

1. Compute directory hash: SHA-256 of the absolute working directory path, truncated to 16 characters.

   echo -n "/absolute/path/to/project" | sha256sum | cut -c1-16
   

2. Shadow repo path: ~/.claude/projects/<project-hash>/checkpoints/<dir-hash>/