What problem does it solve? Re-processing expensive files (PDF parsing, OCR, image analysis) wastes time, and path-based caches break whenever files are moved or renamed. This Skill provides a pattern for caching processing results keyed by file content, so cache entries survive renames and invalidate automatically when content changes. ## Core Features & Use Cases - Content-Hash Cache Keys: Uses chunked SHA-256 hashing of file contents so cache hits survive file moves and renames, with automatic invalidation on content change. - File-Based Storage: Stores each entry as {hash}.json for O(1) lookup with no index file, treating corrupted entries as cache misses. - Service Layer Separation: Keeps extraction functions pure and wraps caching in a separate service layer, supporting --cache/--no-cache CLI options. - Use Case: A CLI tool that extracts text from hundreds of PDFs across repeated runs can skip re-parsing unchanged files even after the folder is reorganized. ## Quick Start Add content-hash based caching to my PDF text extraction pipeline so repeated runs skip unchanged files.